DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Status of Claims
Claims 1-18, 21, and 23-26 are pending.
Claims 1-18, 21, and 23-26 are rejected under 103 on three separate new grounds. Examiner has made these rejections in an earnest attempt to advance prosecution beyond the matter of the claimed extruder temperature. See 103 rejections below for details.
Response to Arguments
Applicant's arguments filed 2/26/2026 have been fully considered and they are persuasive.
Specifically, Applicant has pointed out apparent contradictions between Examiner’s position regarding the melting point of polycarbonate and what is taught in the prior art. Most notably, Applicant has pointed out that the melting point of polycarbonate as taught by boyanmfg.com is considerably lower than 275 °C, rather than higher as Examiner previously believed. Having reviewed several other sources, Examiner now concedes that the melting point of polycarbonate appears to be lower than 275 °C (though some sources disagree).
However, Examiner now wonders if the “injection molding temperature” of a polymer is actually more relevant than the “melting temperature” for the purposes of Scheirs’ melt processing. Indeed, boyanmfg.com teaches that polymers transition to a “viscous flow state” at their melting temperature (see “Tip: The Melting Temperature (Tm), Also Known as Flow Temperature (Tf)”. But boyanmfg also states that “It’s important to note that the injection molding temperature is usually higher than the melting temperature to ensure good flowability of the plastic during processing.” Considering that the reactor 30 of Scheirs comprises an impellor stirrer 40 (Figure 1, paragraph [0053]), it seems undesirable for a polymer feed to be in a highly viscous state when discharged from the extruder 20 into the reactor 30.
Regardless, considering that the rejections of record relied on the apparently false notion that polycarbonate has a melting point above 275 °C, Applicant has substantially undermined said rejections by pointing out evidence to the contrary.
Nevertheless, Examiner maintains that it would be obvious to increase the extruder temperature of Scheirs so as to heat the plastic feedstock in the extruder barrel to a temperature 275 °C or more in order to ensure that the extruder of Scheirs is able to melt any high melting point plastics found in the feed material. This position is now maintained in view of newly cited Maduskar et al. (US 2023/0159834), which, in the context of melting a plastic feedstock in an extruder prior to feeding the melted plastic feedstock into a pyrolysis reactor, expressly teaches heating the plastic feedstock in the extruder to “up to 350° C. or possibly still higher, to ensure melting of the plastic,” (paragraph [0026], third sentence). For further details, see the 103 rejections set forth below over Scheirs (US 2011/0230689) in view of, Maezawa et al. (US 5,608,136), Maduskar et al. (US 2023/0159834), Griffin (US 11,578,271), and Inoue et al. (US 6,881,303).
For the sake of argument, if the motivation provided by Maduskar is not sufficient, there is at least one more reason to modify Scheirs to operate at an extruder temperature above 275 °C. Namely, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Van Meirhaeghe et al. (US 12,338,393) by configuring the extruder heater to heat the plastic feedstock to a temperature of about 350 °C, in order to obtain an extruder which subjects the plastic feedstock to a limited degree of pyrolysis, thereby decreasing the burden on the pyrolysis reactor to conduct the pyrolysis. For further details, see the 103 rejections set forth below over Scheirs in view of, Maezawa, Van Meirhaeghe et al. (US 12,338,393), Griffin, and Inoue.
Furthermore, Examiner respectfully directs Applicant’s attention to the following excerpt from the MPEP:
Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955) (Claimed process which was performed at a temperature between 40°C and 80°C and an acid concentration between 25% and 70% was held to be prima facie obvious over a reference process which differed from the claims only in that the reference process was performed at a temperature of 100°C and an acid concentration of 10%.)
(MPEP 2144.05 II. A.)
There is nothing in the record to suggest that the claimed extruder temperature is in any way critical. The disclosure of Scheirs provides clear indication that the extruder temperature, i.e. the temperature to which plastic feedstock is heated by the extruder, is a result effective variable (e.g. at paragraph [0026]). Furthermore, as explained in detail in the 103 rejections below1 a person having ordinary skill in the art would, in view of Van Meirhaeghe, have a reasonable expectation that it would be workable for the extruder of Scheirs to heat the plastic feed material to a temperature above 275 °C, for example, to a temperature of 350 °C. Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Van Meirhaeghe by configuring the extruder heater to heat the plastic feedstock to a temperature of about 350 °C, simply in order to obtain an extruder which operates to heat the plastic feedstock to a temperature which is predictably workable in view of the prior art. Rejection on this ground is incorporated into the 103 rejections set forth below over Scheirs in view of Maezawa, Van Meirhaeghe, Griffin, and Inoue.
The disclosure of Scheirs aside, the claimed extruder heating temperature of 275 °C or more is by no means patentable, as Van Meirhaeghe anticipates said temperature range and serves as a strong primary refence on which to base a 103 rejection of the claims. Accordingly, a 103 rejection over Van Meirhaeghe in view of Griffin and Inoue is set forth below.
As will be appreciated from the 103 rejections set forth over Van Meirhaeghe in view of Griffin and Inoue below, Van Meirhaeghe anticipates more elements of claim 1 than Scheirs. Thus, Van Meirhaeghe is closer in scope to the invention of claim 1 than Scheirs. However, Examiner still considers Scheirs to be the closest prior art of record with respect to at least dependent claims 10 and 11. This is why Examiner continues to maintain rejections over Scheirs as a primary reference despite the presence of Van Meirhaeghe in the record.
Applicant has argued that the Office has relied on improper hindsight reasoning in making the 103 rejections of record, alleging the use of 7 or 8 references in said rejection(s) is a “clear example of impermissible hindsight” (see page 7 of the 2/26/2026 Remarks). Examiner respectfully disagrees.
First, in response to applicant's argument that the examiner has combined an excessive number of references, reliance on a large number of references in a rejection does not, without more, weigh against the obviousness of the claimed invention. See In re Gorman, 933 F.2d 982, 18 USPQ2d 1885 (Fed. Cir. 1991).
In response to applicant's argument that the examiner's conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
Examiner respectfully contends that the rejections only rely on knowledge which was within the level of ordinary skill in the art at the time the claimed invention was made (i.e. before the effective filing date). Therefore, the rejections of record do not engage in any impermissible hindsight.
Applicant has argued that a person having ordinary skill in the art would not have modified Scheirs to increase the temperature to provide a plastic feedstock of 275 °C or more as claimed (see pages 8-15 of Remarks). Examiner respectfully disagrees.
Examiner maintains that it would have been obvious to one of ordinary skill in the art to increase the extruder temperature to provide a plastic feedstock of 275 °C. See 103 rejections below for details.
In arguing that one would not have modified Scheirs to increase the temperature to provide a plastic feedstock of 275 °C or more, Applicant cites paragraph 4 of the declaration (see page 8 of Remarks).
However, paragraph 4 of the declaration is merely a statement by one of the inventors (Jeffery Gold) asserting that “it would not be obvious to modify the melt processor of Scheirs such that it includes one or more extruder heaters configured for heating the plastic feedstock in the extruder barrel to a temperature of 275°C or more to produce at least semi- molten feedstock as is presently claimed.” Said statement is merely an opinion as a legal conclusion, and thus is not entitled to any weight (MPEP 716.01(c)).
Applicant argues that “plastic that is completely liquefied cannot physically be melt-processed through an extruder. Id. at 6. So even if the Office allegation is correct that Scheirs is processing WEEE with plastics having melting points in excess of 275 C, there would be no motivation to increase the temperature of the melt processor for this reason,” (see page 8 of Remarks). Examiner respectfully disagrees.
It is unclear exactly what Applicant means by the assertion that “plastic that is completely liquefied cannot physically be melt-processed through an extruder”. Is Applicant alleging that melt processing in an extruder like that of Scheirs cannot yield a plastic which is fully melted/molten? It seems Applicant’s arguments are intended to give a reader this impression. However, Applicant’s arguments and declaration do not contain any clearly stated allegation to this effect (such an allegation is, at best, implied by the Remarks and Declaration).
Assuming that Applicant is alleging that an extruder cannot yield, i.e. output at its discharge end, a plastic which is fully melted/molten, Examiner respectfully disagrees.
Applciant’s own specification describes the extruder S107a as being “configured for melting the plastic feedstock” (see paragraph [0307] of the published application) and “configured for directing the molten (or semi-molten) plastic feedstock into the pyrolysis reactor S108a,” (paragraph [0309]). Thus, Applicant’s specification clearly shows that melt processing in an extruder can yield plastic which is fully melted/molten Applicant’s specification does not include any special definition of the word “melting” or “melt”.
Examiner acknowledges the following remarks by Applicant:
plastic that is completely liquefied cannot physically be melt- processed through an extruder. The material in an extruder needs to be viscous enough that it can be pushed laterally through the extruder by the screw. In other words, the extruder screw has to have something to "push" against. A liquid cannot be pushed by an extruder screw.
(Declaration, paragraph 6)
Without conceding to the general correctness of these statements, Examiner nevertheless notes that they ignore that plastic heated in an extruder will be gradually heated as it travels along the length thereof. Thus, the plastic at the outlet end of the extruder will be at a higher temperature than the plastic at the inlet end. Accordingly, plastic in an extruder can be heated such that the plastic melts at or adjacent the outlet end of the extruder, while more recently fed plastic at the inlet end remains solid. This solid plastic at the inlet end will be constantly replenished in a continuous process, and therefore, can provide an extruder with means to “push” the melted plastic at the output end.
Furthermore, melted plastic, being comprised of long chain, high molecular weight compounds, is expected to be viscous. Surely, a plastic can be molten and remain viscous enough for an extruder to “push” it.
Regardless, newly cited Maduskar et al. (US 2023/0159834) explicitly teaches that a melt extruder can convert plastic “into a liquid (melted) state” (paragraph [0026], second sentence). Thus, the preponderance of evidence weighs strongly against Applicant’s assertions concerning the melt processing of liquefied/melted plastic.
Examiner maintains that it is possible for melt processing in an extruder like that of Scheirs to yield a plastic which is fully melted/molten.
If Applicant wishes to maintain the argument at hand in future prosecution, Examiner respectfully requests Applicant clarify the following:
Is Applicant alleging that melt processing in an extruder like that of Scheirs cannot yield a plastic which is fully melted/molten?
Applicant has alleged that the temperature suggested range suggested by Scheirs for the melt processor is selected for the purpose of removing contaminants such as flame retardants, and therefore, one of ordinary skill in the art would allegedly not modify Scheirs to operate at temperatures outside this range (see pages 8-9 of Remarks and paragraph 5 of Declaration). Examiner finds this argument unpersuasive.
Examiner agrees that the melt processing temperature in Scheirs should be selected to be suitable for removal of contaminants such as flame retardants. However, suitability for contaminant removal is merely one factor which one would take into account when selecting proper temperature for the melt processor.
Scheirs paragraph [0026] discloses the following:
Melt processing is conducted for sufficient time and at a suitable temperature to cause the plastic components of the WEEE to become molten. Those skilled in the art will appreciate that the temperature at which the melt processing is conducted will generally depend upon the nature of the plastic components being processed. Generally, the WEEE will be melt processed at a temperature ranging from about 220 °C. to about 260 °C.
The first sentence of paragraph [0026] makes it abundantly clear the melting point of the plastic(s) to be processed is a factor which should be considered when selecting the melt processing temperature.
Examiner reiterates that Scheirs teaches “Generally, the WEEE [waste electrical and electronic equipment, the plastic feedstock processed in Scheirs] will be melt processed at a temperature ranging from about 220° C to about 260° C,” (paragraph [0026]). In view of Scheirs use of the word “generally”, a person having ordinary skill in the art would recognize that this teaching clearly does not limit the heating temperature of the extruder to only temperatures in the range of “220° C to about 260° C”. On the contrary, a person having ordinary skill in the art would recognize that: i) heating temperatures which are higher than 260 °C remain within the scope of Scheirs invention, and ii) such heating temperatures higher than 260 °C would be desirable if necessary to achieve melting of a particular plastic feedstock.
Turning back to the removal of contaminants such as flame retardant, Examiner notes that the is nothing in the record which suggests that temperatures higher than 220-260 °C (e.g. the claimed temperature range of 275 °C or higher) would unsuitable for removing contaminants such as flame retardants, nor does Applicant allege that they would be. Examiner respectfully contends that if melt processing temperatures of 220-260 °C are suitable for removing particular contaminants such as flame retardants, then so too are slightly higher temperatures. A person having ordinary skill in the art would expect this.
In view of the forgoing, Examiner maintains that it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify by configuring the extruder heater to heat the plastic feedstock to a temperature of 275 °C, for the purpose of enabling the extruder of Scheirs to melt high melting point plastic feedstocks.
Applicant has alleged that “when Scheirs describes that 'the WEEE will be melt processed at a temperature ranging from about 220°C to about 260°C' (see Scheirs, paragraph 0026), this would suggest to one of skill in the art that the set point of the melt processor is between 220°C-260°C, not necessarily the WEEE that is being processed,” (page 10 of Remarks and paragraph 7 of Declaration). Examiner respectfully disagrees.
As Applicant admits, Scheirs teaches that “Generally, the WEEE will be melt processed at a temperature ranging from about 220 °C. to about 260 °C,” (paragraph [0026]). The wording of this disclosure is far more easily interpreted as describing the temperature at which the WEEE will be processed, as opposed to the temperature to which the screw is set. Indeed, the disclosure in question describes a temperature at which “WEEE will be melt processed”, but does not reference the melt processor/extruder. If Scheirs were attempting to describe the temperature set point of the melt processor/extruder, would it not specifically reference the melt processor/extruder device?
Furthermore, Examiner reiterates Scheirs teaching to “Melt processing being conducted for sufficient time and at a suitable temperature to cause the plastic components of the WEEE to become molten,” (paragraph [0026]). This disclosure at least suggests that the melt processor/extruder of Scheirs should heat the plastic material therein to a temperature suitable to cause said plastic material to melt.
Examiner respectfully maintains that a person having ordinary skill in the art would understand the disclosure in question as describing a temperature at which the WEEE is to be processed, NOT a temperature to which the extruder itself is heated (with the WEEE being heated to a lower temperature).
Applicant alleges that “The Office has not appreciated that, beyond the technical issues with heating the WEEE of Scheirs to a temperature of 275°C or more, there are operational challenges associated with increasing temperature in an industrial recycling process like Scheirs," (Declaration paragraph 8). Examiner finds this argument unpersuasive.
It must be understood that every engineering decision necessarily comes with drawbacks and/or challenges. Thus, the notion that a modification would be accompanied by drawbacks is not sufficient to show that said modification would be non-obvious, especially when there is some motivation to make said modification in the first place. When considering modifying Scheirs so as to heat plastic in the extruder to a temperature of 275°C there is motivation to do so as described in the separate rejections made over Scheirs below.
Furthermore, the specific challenges/drawbacks alleged by Applicant are increase energy consumption and therefore, financial costs. However, Examiner respectfully questions the extent to which operating the extruder of Scheirs at higher temperatures would actually increase the energy consumption of Scheirs’ system as a whole. Would not heating polymer to a higher temperature in the extruder reduce the amount of heating the reactor must achieve, thereby reducing the reactor’s energy consumption in proportion with increases in extruder energy consumption?
Applicant has argued that it would not be obvious to modify the process of Scheirs to melt the plastics feedstock because the plastic feedstock of Scheirs is WEEE, which can contain thermosetting polymers such as polyurethane (see pages 13-14 of Remarks). Examiner finds this argument unpersuasive.
First, a stream of WEEE does not necessarily contain thermosetting polymers. Indeed, Example 1 in Scheirs describes processing WEEE which does not contain any thermosets, or at least Scheirs does not mention the presence of any thermosets, despite mentioning several specific polymers (paragraph [0060]). Even in the event that a WEEE stream does contain thermosetting polymers, there is no guarantee that it contains these in a significant amount relative to the total amount of plastic in the feed.
Regardless, the fact remains that Scheirs teaches melting the plastic components in the waste to be processed therein. For example, Scheirs teaches that “Melt processing is conducted for sufficient time and at a suitable temperature to cause the plastic components of the WEEE to become molten,” (paragraph [0026]). Considering that Scheirs clearly aims to melt the plastic components in the WEEE feedstock, the notion that said plastic components might contain thermosets which are non-melting is insufficient to dissuade one from taking steps to ensure that complete melting of the plastic portion is achieved to the extent possible.
Applicant’s other arguments not specifically addressed above have been considered, but are moot, as they do not apply to the new grounds of rejection set forth below.
The following are new rejections.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 1-18, 21, 24, and 26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Scheirs (US 2011/0230689) in view of Maezawa et al. (US 5,608,136), hereafter referred to as Maezawa, Maduskar et al. (US 2023/0159834), hereafter referred to as Maduskar, Griffin (US 11,578,271), and Inoue et al. (US 6,881,303), hereafter referred to as Inoue.
With regard to claims 1, 2, and 26: Scheirs teaches a system for pyrolyzing plastic feedstock comprising post-consumer and/or post-industrial plastics (abstract, Figure 1, paragraphs [0053]-[0061]), the system comprising:
An extruder (melt mixing device) 20 configured for melting the plastic feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053], [0054], and [0060]).
Wherein the extruder 20 is configured to heat the plastic feedstock to a high temperature, e.g. a temperature in the range of 220-260 °C so as to produce an at least semi-molten feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0026], [0053] and [0060], claim 6).
A reactor comprising a reactor vessel 30 defining an internal column configured for receiving and pyrolyzing the at least semi-molten feedstock and a plurality of heaters 50 configured for heating the feedstock in the reactor vessel's internal volume to a temperature ranging from 360°C to 450°C (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053] and [0054]).
Scheirs is silent to one or more extruder heaters configured for heating the plastic feedstock in the extruder barrel to a temperature of 275 °C or more to produce the at least semi-molten feedstock.
However, as discussed above, Scheirs does teach that the extruder 20 is configured to heat the plastic feedstock to a high temperature, e.g. a temperature in the range of 220-260 °C so as to produce an at least semi-molten feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0026], [0053] and [0060], claim 6). It is thus understood that the extruder of Scheirs must be somehow capable of heating the plastic feed material to high temperature, whether that be through the use of a heater, by shear heating the feed material, or some combination thereof.
Regardless, Scheirs is silent to any particular means by which heating of the plastic feed in the extruder is accomplished. Clearly, if one were to practically implement the device of Scheirs, i.e. construct a real-world, working example thereof, then they must select a particular means for heating the plastic feed material in the extruder. Therefore, in order to practically implement the device of Scheirs, a person having ordinary skill in the art would be motivated to search the prior art for suitable means by which heating of the plastic feed material in the extruder can be accomplished.
It is notoriously well-known in the art to provide extruders with heaters for heating and melting plastic feedstock therein. For example, Maezawa teaches an apparatus for processing plastic said apparatus comprising an extruder 12 having an extruder barrel (main unit) 13 arranged for heating and mixing a plastic feedstock (polymeric material) A, wherein the extruder barrel 13 is provided with at least one extruder heater 16 for heating plastic feedstock in the extruder barrel to a high temperature to produce an at least semi-molten, i.e. softened, feedstock (Figure 3, paragraph, Column 6 lines 40-45, Column 17 Line 25-Column 18 line 10). A person having ordinary skill in the art would recognize that including one or more extruder heaters for heating the extruder barrel of Scheirs (and the plastic feedstock therein) would be advantageous, as such a heating element would be able to at least assist in heating the plastic feedstock to a desired temperature so as to melt said plastic feedstock and form an at least semi-molten feedstock.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Scheirs in view of Maezawa by adding one or more extruder heaters configured for heating the plastic feedstock in the extruder barrel to a high temperature to produce the at least semi-molten feedstock, i.e. by melting the plastic feedstock, in order to obtain a system wherein the extruder is desirably provided with a predictably workable means of heating of plastic feedstock in the extruder to accomplish the desired melting thereof.
Modified Scheirs remains silent to the extruder heater being configured to heat the plastic feedstock to a temperature of 275 °C or more to produce the at least semi-molten feedstock.
However, the extruder (melt mixing device) 20 of Scheirs is intended to melt plastic feedstock processed therein (paragraphs [0024]-[0029], [0053], [0060]). Indeed, Scheirs teaches that “Melt processing is conducted for sufficient time and at a suitable temperature to cause the plastic components of the WEEE to become molten,” (paragraph [0026]). Scheirs further teaches that “Those skilled in the art will appreciate that the temperature at which the melt processing is conducted will generally depend upon the nature of the plastic components being processed,” (paragraph [0026]), thereby clearly indicating that the temperature to which the extruder heats the plastic feedstock is a result effective variable. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It is acknowledged that Scheirs teaches that “Generally, the WEEE [waste electrical and electronic equipment, the plastic feedstock processed in Scheirs] will be melt processed at a temperature ranging from about 220° C to about 260° C,” (paragraph [0026]). However, in view of Scheirs use of the word “generally”, a person having ordinary skill in the art would recognize that this teaching clearly does not limit the heating temperature of the extruder to only temperatures in the range of “220° C to about 260° C”. On the contrary, a person having ordinary skill in the art would recognize that: i) heating temperatures which are higher than 260 °C remain within the scope of Scheirs invention, and ii) such heating temperatures higher than 260 °C would be desirable if deemed necessary to achieve melting of a particular plastic feedstock.
Maduskar, drawn to pyrolysis of a plastic feedstock (abstract), teaches melting plastic feedstock in a melt extruder 130 prior to feeding the melted feedstock into a pyrolysis reactor 150 (Figure 1, paragraph [0063]). Maduskar teaches that the melt extruder can be operated such that “the temperature of the plastic during extrusion can be 150° C. or more, or 170° C. or more, such as up to 350° C. or possibly still higher, to ensure melting of the plastic,” (paragraph [0026], third sentence). Additionally, Maduskar teaches that "the temperature of the plastic during extrusion can be greater than the highest melting point of a polymer in the plastic feedstock,” (paragraph [0026], fourth sentence; emphasis added).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Maduskar by configuring the extruder heater to heat the plastic feedstock to a temperature above 275 °C, e.g. a temperature as high as 350 °C of higher, to produce the at least semi-molten feedstock, in order to ensure that the extruder of Scheirs is able to melt any high melting point plastics found in the feed material.
Modified Scheirs is silent to one or more temperature sensors configured for sensing the temperature of the at least semi-molten feedstock in the reactor vessel; and a pyrolysis control system configured for: at least temporarily storing a target temperature value for the at least semi-molten feedstock in the reactor vessel, monitoring the temperature of the at least semi-molten feedstock in the reactor vessel as measured by the one or more temperature sensors, and in response to the temperature measured by the one or more temperature sensors, controlling the one or more heaters to maintain the temperature of the at least semi-molten feedstock within a defined tolerance relative to the target temperature value, wherein the pyrolysis control system is configured as a feedback loop or a feedforward loop.
However, temperature control systems which maintain pyrolysis reactors at a target temperature are known in the art. For example, Griffin teaches a pyrolysis system comprising a reactor vessel 300, at least one temperature sensor (thermocouple probe) 505 configured for sensing the temperature within the reactor vessel 300, and a pyrolysis control system comprised of thermocouple reader 510 and throttle controller 515, the pyrolysis control system configured for: at least temporarily storing a target temperature value for the reactor vessel 300, monitoring the temperature in the reactor vessel as measured by the at least one temperature sensor 505, and in response to the temperature measured by the at least one temperature sensor, controlling one or more heaters (burners) 400 to maintain the temperature of the at least semi-molten feedstock above and below predetermined thresholds, wherein the control system is configured as feedback loop, i.e. a thermocouple feedback loop 500 (Figure 10, Column 11 Lines 34-60). Griffin expressly teaches that “The thermocouple feedback loop 500 automatically maintains the target temperature within the reactor 300,” (Column 11 Lines 37-39). When this teaching regarding maintaining of target temperature is considered in combination with the teaching(s) to predetermined temperature thresholds (Column 11 Lines 48-59), it would at least suggest that said predetermined temperature thresholds are temperatures corresponding to a defined tolerance from a target temperature value.
The benefits of including such a temperature control system would be clear to one of ordinary skill in the art. Namely, a person having ordinary skill in the art would recognize that such a temperature control system can automatically maintain a pyrolysis reactor vessel at a range of temperatures necessary for pyrolysis.
As for temperature control systems which directly measure the temperature of molten plastic feedstocks, these too are known in the art. For example, Inoue teaches a plastic pyrolysis system comprising: a reactor vessel (pyrolysis vessel) 3 configured for pyrolyzing a plastic feedstock in a molten state, at least one temperature sensor (temperature measuring device) 8 provided for measuring the temperature of melted plastic within the reactor vessel 3 (indeed the temperature sensor 8 is illustrated as being in direct contact with the melted plastic within the vessel 3), and a pyrolysis control system comprised of temperature recorder 9 and temperature regulator (Figure 1, Column 6 Lines 15-55). It is implicit that a temperature control system which operates based on temperature measurements taken directly from a pyrolysis feedstock within a reactor will be capable of controlling the temperature of the pyrolysis feedstock itself (as opposed to a temperature of the reactor vessel).
In Scheirs, the reactor vessel 30 pyrolyzes plastic feedstock in a molten state (paragraphs [0053]-[0054]). Furthermore, Scheirs describes the operating temperature of reactor vessel specifically in terms of the temperature to which the reactor vessel heats the molten feedstock within its interior (paragraphs [0037] and [0054]). Thus, it would be clear to one of ordinary skill in the art would recognize that a temperature control system which directly measures and thereby controls the temperature of molten plastic within a pyrolysis reactor vessel is particularly suitable for use in a system like that of Scheirs.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Griffin and Inoue by adding one or more temperature sensors configured for sensing the temperature of the at least semi-molten feedstock in the reactor vessel; and a pyrolysis control system configured for: at least temporarily storing a target temperature value for the at least semi-molten feedstock in the reactor vessel, monitoring the temperature of the at least semi-molten feedstock in the reactor vessel as measured by the one or more temperature sensors, and in response to the temperature measured by the one or more temperature sensors, controlling the one or more heaters to maintain the temperature of the at least semi-molten feedstock within a defined tolerance relative to the target temperature value, wherein the pyrolysis control system is configured as a feedback loop, in order to obtain a system that is capable of automatically maintaining the temperature of the at least semi-molten feedstock within the reactor at a desired temperature.
Modified Scheirs is silent to the defined tolerance being within 10 °C of the target temperature value.
However, a person having ordinary skill in the art would recognize that the magnitude of the defined tolerance is a result effective variable in the temperature control. In other words, a person having ordinary skill in the art would recognize that if the defined tolerance is too great, the actual temperature of the at least semi-molten feedstock will be allowed to stray farther than desired from the target temperature. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the defined tolerance, such that the defined tolerance is within 10 °C of (i.e. less than or equal to 10 °C from) the target temperature value, in order to obtain a control device which does not allow the actual temperature to stray too far from the target temperature.
Modified Scheirs is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 342 hours or more during a time period of 360 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Scheirs by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 360 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 342 hours or more during a 360 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 3: Modified Scheirs is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 576 hours or more during a time period of 720 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 720 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Scheirs by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 720 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 576 hours or more during a 720 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 4: Modified Scheirs is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 756 hours or more during a time period of 1080 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 1080 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Scheirs by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 1080 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 756 hours or more during a 1080 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 5: Modified Scheirs is silent to the volume of the reactor vessel being between 100 and 20,000 gallons.
However, a person having ordinary skill in the art would recognize that the volume of the reactor is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if the volume of the reactor vessel is too low, it will not be able to process feedstock at a rate required to meet demand. On the other hand, if the volume is too high, the reactor would require an excessive amount of material and capital to construct relative the amount of plastic it is required to process. Furthermore, if the reactor volume is far in excess of the volume of plastic feedstock which will be fed to it per unit time, the functionality of said reactor vessel may be adversely affected due to the plastic level therein being excessively low, e.g. relative the positioning of the heaters 50 and the agitator 40. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the volume of the reactor vessel so that it is between 100 and 20,000 gallons, in order to obtain a reactor which is appropriately sized to meet a particular demand for plastic processing.
With regard to claim 6: Modified Scheirs is silent to the reactor vessel being configured to maintain a pressure between -7.5 and 14.5 psig.
However, a person having ordinary skill in the art would recognize that the pressure within the reactor vessel is a result effective variable in modified Scheirs. In particular, a person having ordinary skill in the art would recognize that the pressure within the reactor 30 will determine which pyrolysis products will vaporize and pass out of the reactor 30 to fractionator 70 and which will remain behind. If the pressure in the reactor is too high, pyrolysis products will undesirably remain in the pyrolysis residue within the reactor 30 as opposed to vaporizing and passing into the fractionator 70. If the pressure in the reactor is too low, heavier pyrolysis products will be allowed to vaporize, which will result in the fractionator 70 receiving heavier than desired pyrolysis products. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the operating pressure of the reactor, such that the reactor vessel is configured to maintain a pressure between -7.5 and 14.5 psig, in order to obtain a system wherein lighter pyrolysis products are able to vaporize and pass to the fractionator while heavier pyrolysis products are prevented from vaporizing and thus remain in the pyrolysis reactor.
With regard to claim 7: Modified Scheirs is silent to the heaters being configured for applying heat to the plastic feedstock at a heat density between 5 and 55 W/in2.
However, a person having ordinary skill in the art would recognize that the heat density (power output per unit surface area) of the heaters is a result effective variable in modified Scheirs. In particular, a person having ordinary skill in the art would recognize that if the heat density of the heaters is too low, then said heaters will be incapable of supplying heat to a discrete amount of plastic feedstock at rates quick enough to effect pyrolysis. On the other hand, if heat density of the heaters is too high, energy will be wasted, and pyrolysis reactions within the reactor may proceed to an extent further than desired. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the heat density of the heaters, such that the heaters are configured to apply heat to the plastic feedstock at a heat density between 5 and 55 W/in2, in order to obtain a heaters which are capable of effecting pyrolysis of the plastic feedstock without wasting energy and/or causing pyrolysis to proceed further than a desired extent.
With regard to claims 8, 10, and 11: The plurality of heaters 50 are an array of electric heaters (FIR heaters) which are vertically oriented and extend into an interior volume of the reactor vessel (Figure 1, paragraph [0045] and [0054]-[0055]).
With regard to claim 9: The plurality of heaters 50 are positioned around (i.e. near) sides (i.e. vertical sidewall(s)) of the reactor vessel (Figure 1, paragraph [0045] and [0054]-[0055]).
With regard to claim 12: The reactor vessel includes an agitator (mixing element) 40 configured for stirring the plastic feedstock during pyrolysis (Figure 1, paragraph [0053]).
With regard to claim 13: The agitator 40 of modified Scheirs is at least capable of operating continuously so as to continuously stir the plastic feedstock within the reactor vessel during pyrolysis. Accordingly, modified Scheirs satisfies the claim language regarding the agitator being configured to continuously stir the plastic feedstock within the reactor vessel during pyrolysis. See MPEP 2114 for guidance.
In the unlikely alternative, it has been established that continuous operation is obvious over a prior art batch process (see MPEP 2144.04(V)E). Furthermore, a person having ordinary skill in the art would recognize that continuous stirring during pyrolysis is advantageous, as such continuous stirring would ensure that material within the reactor is more uniformly heated and pyrolyzed. Accordingly, in the unlikely event that the agitator 40 of modified Scheirs is not capable of continuous stirring, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by configuring the agitator 40 to operate so as to continuously stir the plastic feedstock within the reactor vessel during pyrolysis, in order to obtain a device which is capable of, by virtue of continuous stirring, more uniformly heating and pyrolysing the plastic feedstock.
With regard to claim 14: As discussed in the rejection of claim 13 above, the agitator of Scheirs is capable of continuously stirring the plastic feedstock within the reactor vessel during pyrolysis. Accordingly, it is understood that the agitator is capable of continuously producing average liquid flow velocities within the reactor.
Modified Scheirs is silent to the agitator being configured to continuously produce average liquid flow velocities specifically between 0.2 and 10 m/s.
However, a person having ordinary skill in the art would recognize that the average liquid flow velocity which the agitator is capable of producing is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if said agitator is incapable of inducing an average liquid flow velocity above a particular threshold, it will be incapable of properly stirring the plastic material within the reactor so as to ensure uniform heating and pyrolysis of said plastic material. On the other hand, if the agitator is configured to produce an average liquid flow velocity which is excessively high, it will waste energy by stirring (or attempting to stir) the plastic material at a rate which is greater than is necessary or possible. Furthermore, an agitator which is configured to produce an excessively high average liquid flow velocity will be subjected to greater stresses than one which stirs liquid more slowly. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the rate at which the agitator stirs plastic material within the reactor, i.e. by configuring the agitator to continuously produce average liquid flow velocities between 0.2 and 10 m/s within the reactor, in order to obtain a system wherein the agitator is capable of effectively stirring the plastic material so as to ensure uniform heating and pyrolysis of the plastic material without the agitator wasting energy or subject itself to excessive stress.
With regard to claim 15: As discussed in the rejection of claim 13 above, the agitator of Scheirs is capable of continuously stirring the plastic feedstock within the reactor vessel during pyrolysis. Accordingly, it is understood that the agitator is capable of continuously producing average liquid flow velocities within the reactor.
Modified Scheirs is silent to the agitator being configured to continuously produce average liquid flow velocities specifically between 0.5 and 6 m/s.
However, a person having ordinary skill in the art would recognize that the average liquid flow velocity which the agitator is capable of producing is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if said agitator is incapable of inducing an average liquid flow velocity above a particular threshold, it will be incapable of properly stirring the plastic material within the reactor so as to ensure uniform heating and pyrolysis of said plastic material. On the other hand, if the agitator is configured to produce an average liquid flow velocity which is excessively high, it will waste energy by stirring (or attempting to stir) the plastic material at a rate which is greater than is necessary or possible. Furthermore, an agitator which is configured to produce an excessively high average liquid flow velocity will be subjected to greater stresses than one which stirs liquid more slowly. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the rate at which the agitator stirs plastic material within the reactor, i.e. by configuring the agitator to continuously produce average liquid flow velocities between 0.5 and 6 m/s within the reactor, in order to obtain a system wherein the agitator is capable of effectively stirring the plastic material so as to ensure uniform heating and pyrolysis of the plastic material without the agitator wasting energy or subject itself to excessive stress.
With regard to claims 16 and 17: In Figure 1 of Scheirs, the agitator 40 is show as comprising a vertically oriented drive shaft and a plurality of stirring elements each mounted on the drive shaft and comprising a plurality of plurality of blades extending radially outward from the drive shaft (Figure 1, see annotated Figure 1 below).
Scheirs teaches that the agitator 40 may be an “impellor stirrer” (paragraph [0053]). This teaching at least suggests that the stirring elements depicted in Figure 1 (see annotated Figure 1 below) are impellers and that the blades of each of said stirring elements are impeller blades. Accordingly, it would at least be obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by configuring the agitator such that the plurality of stirring elements mounted on the drive shaft are impellers, and such that the plural blades of each of the stirring elements are impeller blades, in order to obtain a system having a predictably functional agitator which is congruent with the suggestions of Scheirs.
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With regard to claim 18: The reactor 30 further comprises at least one vapor outlet configured for directing hydrocarbon vapor generated during pyrolysis out of the reactor vessel, said at least one vapor outlet connecting the reactor vessel to the fractionator 70 (Figure 1, paragraphs [0054] and [0055]).
With regard to claim 21: In modified Scheirs, the plastic feedstock may be supplied by melt mixing device (e.g. an extruder) 20 as a stream molten or semi-molten material (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053] and [0060]). The reactor vessel of pyrolysis reactor 30 is configured to pyrolyze the stream of molten or semi-molten material (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053] and [0060]).
The melt mixing device 20 of modified Scheirs is at least capable of operating continuously so as to supply the plastic feedstock as a continuous stream of molten or semi-molten material. Accordingly, modified Scheirs satisfies the claim language regarding the plastic feedstock being supplied as a continuous stream molten or semi-molten material. See MPEP 2114 for guidance.
In the unlikely alternative, it has been established that continuous operation is obvious over a prior art batch process (see MPEP 2144.04(V)E). Accordingly, in the unlikely event that the melt mixing device of modified Scheirs is not capable of supplying the plastic feedstock as a continuous stream, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by configuring the melt mixing device 20 to operate continuously so as to supply the plastic feedstock as a continuous stream molten or semi-molten material, in order to obtain a device which is predictably capable of continuous operation.
With regard to claim 24: Modified Scheirs remains silent to the one or more temperature sensors being arranged vertically.
However, Inoue teaches temperature sensor (temperature measuring device) 8 which is vertically arranged, said temperature sensor being provided for measuring the temperature of melted plastic within a reactor vessel 3 (Figure 1, Column 6 Lines 15-55). In view of Inoue, a person having ordinary skill in the art would recognize that a vertically arranged temperature sensor is suitable for use in the system of Scheirs.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Inoue by arranging the at least one temperature sensor vertically, in order to obtain a system having a predictably functional temperature sensor.
Claim(s) 23-25 is/are rejected under 35 U.S.C. 103 as being unpatentable over Scheirs in view of Maezawa, Maduskar, Griffin, and Inoue as applied to claims 1, 2, and 26 above, and in further view of Winters (US 2,246,563).
With regard to claims 23-25: Scheirs is silent to the one or more temperature sensors being arranged along an internal wall of the reactor; the one or more temperature sensors being arranged vertically; and pyrolysis control system being configured for: at least temporarily storing a target liquid bath level for the liquid bath in the reactor vessel; monitoring a liquid bath level inside the reactor as measured by the one or more temperature sensors; and in response to the liquid bath level measured by the one or more temperature sensors, controlling feedstock input and/or product output to maintain the liquid bath level inside the reactor within a defined tolerance relative to the target liquid bath level.
However, level control systems which determine liquid level using a plurality of temperature sensors arranged along an internal wall of a vessel are known in the art. For example, Winters teaches a system comprising: a vessel 1; a temperature sensor (thermocouple) 5 arranged along an internal wall of the vessel; and a control system configured for: at least temporarily storing a target liquid level for the liquid in the vessel 1, monitoring a liquid level inside the vessel 1 as measured by the one or more temperature sensors 5, and controlling liquid output to maintain the liquid level in the vessel 1 within a defined tolerance relative the target level (Figure 1, Page 1 Left column Line 49-page 2 left column line 51, especially page 1 right column lines 35-60).
Winters teaches that a level control system of this type is “is more positive and accurate than float type controllers, particularly as applied to controlling the liquid level in vessels handling heated hydrocarbons comprising heavy oils which tend to deposit coke,” (Page 2 Left column lines 47-52). A person having ordinary skill in the art would recognize that said advantages are applicable to the flow of liquid level in pyrolysis reactors holding molten plastic, like the reactor of Scheirs, as molten plastic is a heated heavy organic liquid which will tend to deposit coke when undergoing pyrolysis. Furthermore, a person having ordinary skill in the art would recognize that some plastics, e.g. polyethylene, polypropylene, polystyrene, etc., are hydrocarbons.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Winters by configuring the one or more temperature sensor to be arranged along an internal wall of the reactor, and by further configuring the pyrolysis control to: at least temporarily storing a target liquid bath level for the liquid bath in the reactor vessel; monitoring a liquid bath level inside the reactor as measured by the one or more temperature sensors; and in response to the liquid bath level measured by the one or more temperature sensors, controlling product output to maintain the liquid bath level inside the reactor within a defined tolerance relative to the target liquid bath level, in order to provide the system of Scheirs with a means of controlling the level of the plastic feedstock within the reactor vessel, said means being more positive and accurate than a float type controller.
Modified Scheirs remains silent to the one or more temperature sensors being arranged vertically.
However, Winters teaches an additional embodiment wherein the vessel 20 has a plurality of temperature sensors (thermocouples) P1-P7 arranged vertically, i.e. in a vertical line, along an internal wall of the vessel (Figure 2, Page 2 Left Column Line 53-Page 2 Right Column Line 75). A person having ordinary skill in the art would recognize that, if a vessel provided with a control system for monitoring and controlling liquid level using one or more temperature sensors is provided with a plurality of temperature sensors arranged vertically, i.e. in a vertical line, along an internal wall of the vessel, then the control system would be capable of more accurately determining liquid level in the vessel across a wider array of potential liquid levels, in comparison to a similar system having only one temperature sensor.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Winters by configuring the one or more temperature sensor to be a plurality of temperature sensors arranged vertically, i.e. in a vertical line, along an internal wall of the reactor, in order to obtain a system which is capable of more accurately determining liquid level in the vessel across a wider array of potential liquid levels, in comparison to a similar system having only one temperature sensor.
Claim(s) 1-18, 21, 24, and 26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Scheirs in view of Maezawa, Van Meirhaeghe, et al. (US 12,338,393), hereafter referred to as Van Meirhaeghe, Griffin, and Inoue.
With regard to claims 1 2, and 26: Scheirs teaches a system for pyrolyzing plastic feedstock comprising post-consumer and/or post-industrial plastics (abstract, Figure 1, paragraphs [0053]-[0061]), the system comprising:
An extruder (melt mixing device) 20 configured for melting the plastic feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053], [0054], and [0060]).
Wherein the extruder 20 is configured to heat the plastic feedstock to a high temperature, e.g. a temperature in the range of 220-260 °C so as to produce an at least semi-molten feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0026], [0053] and [0060], claim 6).
A reactor comprising a reactor vessel 30 defining an internal column configured for receiving and pyrolyzing the at least semi-molten feedstock and a plurality of heaters 50 configured for heating the feedstock in the reactor vessel's internal volume to a temperature ranging from 360°C to 450°C (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053] and [0054]).
Scheirs is silent to one or more extruder heaters configured for heating the plastic feedstock in the extruder barrel to a temperature of 275 °C or more to produce the at least semi-molten feedstock.
However, as discussed above, Scheirs does teach that the extruder 20 is configured to heat the plastic feedstock to a high temperature, e.g. a temperature in the range of 220-260 °C so as to produce an at least semi-molten feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0026], [0053] and [0060], claim 6). It is thus understood that the extruder of Scheirs must be somehow capable of heating the plastic feed material to high temperature, whether that be through the use of a heater, by shear heating the feed material, or some combination thereof.
Regardless, Scheirs is silent to any particular means by which heating of the plastic feed in the extruder is accomplished. Clearly, if one were to practically implement the device of Scheirs, i.e. construct a real-world, working example thereof, then they must select a particular means for heating the plastic feed material in the extruder. Therefore, in order to practically implement the device of Scheirs, a person having ordinary skill in the art would be motivated to search the prior art for suitable means by which heating of the plastic feed material in the extruder can be accomplished.
It is notoriously well-known in the art to provide extruders with heaters for heating and melting plastic feedstock therein. For example, Maezawa teaches an apparatus for processing plastic said apparatus comprising an extruder 12 having an extruder barrel (main unit) 13 arranged for heating and mixing a plastic feedstock (polymeric material) A, wherein the extruder barrel 13 is provided with at least one extruder heater 16 for heating plastic feedstock in the extruder barrel to a high temperature to produce an at least semi-molten, i.e. softened, feedstock (Figure 3, paragraph, Column 6 lines 40-45, Column 17 Line 25-Column 18 line 10). A person having ordinary skill in the art would recognize that including one or more extruder heaters for heating the extruder barrel of Scheirs (and the plastic feedstock therein) would be advantageous, as such a heating element would be able to at least assist in heating the plastic feedstock to a desired temperature so as to melt said plastic feedstock and form an at least semi-molten feedstock.
It would have been obvious to one of ordinary skill in the art before the effective filing date to modify Scheirs in view of Maezawa by adding one or more extruder heaters configured for heating the plastic feedstock in the extruder barrel to a high temperature to produce the at least semi-molten feedstock, i.e. by melting the plastic feedstock, in order to obtain a system wherein the extruder is desirably provided with a predictably workable means of heating of plastic feedstock in the extruder to accomplish the desired melting thereof.
Modified Scheirs remains silent to the extruder heater being configured to heat the plastic feedstock to a temperature of 275 °C or more to produce the at least semi-molten feedstock.
The extruder (melt mixing device) 20 of Scheirs is intended to melt plastic feedstock processed therein (paragraphs [0024]-[0029], [0053], [0060]). Indeed, Scheirs teaches that “Melt processing is conducted for sufficient time and at a suitable temperature to cause the plastic components of the WEEE to become molten,” (paragraph [0026]). Scheirs further teaches that “Those skilled in the art will appreciate that the temperature at which the melt processing is conducted will generally depend upon the nature of the plastic components being processed,” (paragraph [0026]), thereby clearly indicating that the temperature to which the extruder heats the plastic feedstock is a result effective variable. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It is acknowledged that Scheirs teaches that “Generally, the WEEE [waste electrical and electronic equipment, the plastic feedstock processed in Scheirs] will be melt processed at a temperature ranging from about 220° C to about 260° C,” (paragraph [0026]). However, in view of Scheirs use of the word “generally”, a person having ordinary skill in the art would recognize that this teaching clearly does not limit the heating temperature of the extruder to only temperatures in the range of “220° C to about 260° C”. On the contrary, a person having ordinary skill in the art would recognize that heating temperatures which are higher than 260 °C remain within the scope of Scheirs invention.
Van Meirhaeghe, drawn to pyrolysis of a plastic feedstock (abstract), teaches melting plastic feedstock in an extruder 200 prior to feeding the melted feedstock into a pyrolysis reactor 101 (Figure 1, Column 15 Line 65-Column 17 Line 30). Van Meirhaeghe teaches that the extruder operates to discharge the plastic feedstock heated therein at a temperature of 350 °C such that said feedstock is an at least partially molten state (Column 11 Lines 15-30, Column 20 Lines 1-21). Notably, Van Meirhaeghe teaches that the plastic feedstock processed in the extruder may include inert material such as glass, sand, and aluminum in addition to plastic material (Column 11 Lines 15-30). Thus, in view of Van Meirhaeghe, a person having ordinary skill in the art would have a reasonable expectation that it would be workable for the extruder of Scheirs to heat the plastic feed material to a temperature above 275 °C, for example, to a temperature of 350 °C.
Furthermore, Van Meirhaeghe indicates that by heating plastic material in the extruder 200 to a temperature of about 330 °C, a limited degree of pyrolysis will occur, releasing some hydrocarbon vapors (Column 20 Lines 10-17). Note: It is understood that the plastic in the extruder of Van Meirhaeghe is heated to 330 °C in the course of heating to 350 °C as taught. A person having ordinary skill in the art would recognize that by conducting limited pyrolysis in the extruder screw, one could advantageously decrease the burden on the pyrolysis reactor to conduct the pyrolysis, i.e. by subjecting the plastic feedstock to early stages of pyrolysis before it even enters the pyrolysis reactor.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Van Meirhaeghe by: configuring the extruder heater to heat the plastic feedstock to a temperature of about 350 °C, in order to:
1) obtain an extruder which operates to heat the plastic feedstock to a temperature which is predictably workable in view of the prior art; AND/OR
2) obtain an extruder which subjects the plastic feedstock to a limited degree of pyrolysis, thereby decreasing the burden on the pyrolysis reactor to conduct the pyrolysis.
Modified Scheirs is silent to one or more temperature sensors configured for sensing the temperature of the at least semi-molten feedstock in the reactor vessel; and a pyrolysis control system configured for: at least temporarily storing a target temperature value for the at least semi-molten feedstock in the reactor vessel, monitoring the temperature of the at least semi-molten feedstock in the reactor vessel as measured by the one or more temperature sensors, and in response to the temperature measured by the one or more temperature sensors, controlling the one or more heaters to maintain the temperature of the at least semi-molten feedstock within a defined tolerance relative to the target temperature value, wherein the pyrolysis control system is configured as a feedback loop or a feedforward loop.
However, temperature control systems which maintain pyrolysis reactors at a target temperature are known in the art. For example, Griffin teaches a pyrolysis system comprising a reactor vessel 300, at least one temperature sensor (thermocouple probe) 505 configured for sensing the temperature within the reactor vessel 300, and a pyrolysis control system comprised of thermocouple reader 510 and throttle controller 515, the pyrolysis control system configured for: at least temporarily storing a target temperature value for the reactor vessel 300, monitoring the temperature in the reactor vessel as measured by the at least one temperature sensor 505, and in response to the temperature measured by the at least one temperature sensor, controlling one or more heaters (burners) 400 to maintain the temperature of the at least semi-molten feedstock above and below predetermined thresholds, wherein the control system is configured as feedback loop, i.e. a thermocouple feedback loop 500 (Figure 10, Column 11 Lines 34-60). Griffin expressly teaches that “The thermocouple feedback loop 500 automatically maintains the target temperature within the reactor 300,” (Column 11 Lines 37-39). When this teaching regarding maintaining of target temperature is considered in combination with the teaching(s) to predetermined temperature thresholds (Column 11 Lines 48-59), it would at least suggest that said predetermined temperature thresholds are temperatures corresponding to a defined tolerance from a target temperature value.
The benefits of including such a temperature control system would be clear to one of ordinary skill in the art. Namely, a person having ordinary skill in the art would recognize that such a temperature control system can automatically maintain a pyrolysis reactor vessel at a range of temperatures necessary for pyrolysis.
As for temperature control systems which directly measure the temperature of molten plastic feedstocks, these too are known in the art. For example, Inoue teaches a plastic pyrolysis system comprising: a reactor vessel (pyrolysis vessel) 3 configured for pyrolyzing a plastic feedstock in a molten state, at least one temperature sensor (temperature measuring device) 8 provided for measuring the temperature of melted plastic within the reactor vessel 3 (indeed the temperature sensor 8 is illustrated as being in direct contact with the melted plastic within the vessel 3), and a pyrolysis control system comprised of temperature recorder 9 and temperature regulator (Figure 1, Column 6 Lines 15-55). It is implicit that a temperature control system which operates based on temperature measurements taken directly from a pyrolysis feedstock within a reactor will be capable of controlling the temperature of the pyrolysis feedstock itself (as opposed to a temperature of the reactor vessel).
In Scheirs, the reactor vessel 30 pyrolyzes plastic feedstock in a molten state (paragraphs [0053]-[0054]). Furthermore, Scheirs describes the operating temperature of reactor vessel specifically in terms of the temperature to which the reactor vessel heats the molten feedstock within its interior (paragraphs [0037] and [0054]). Thus, it would be clear to one of ordinary skill in the art would recognize that a temperature control system which directly measures and thereby controls the temperature of molten plastic within a pyrolysis reactor vessel is particularly suitable for use in a system like that of Scheirs.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Griffin and Inoue by adding one or more temperature sensors configured for sensing the temperature of the at least semi-molten feedstock in the reactor vessel; and a pyrolysis control system configured for: at least temporarily storing a target temperature value for the at least semi-molten feedstock in the reactor vessel, monitoring the temperature of the at least semi-molten feedstock in the reactor vessel as measured by the one or more temperature sensors, and in response to the temperature measured by the one or more temperature sensors, controlling the one or more heaters to maintain the temperature of the at least semi-molten feedstock within a defined tolerance relative to the target temperature value, wherein the pyrolysis control system is configured as a feedback loop, in order to obtain a system that is capable of automatically maintaining the temperature of the at least semi-molten feedstock within the reactor at a desired temperature.
Modified Scheirs is silent to the defined tolerance being within 10 °C of the target temperature value.
However, a person having ordinary skill in the art would recognize that the magnitude of the defined tolerance is a result effective variable in the temperature control. In other words, a person having ordinary skill in the art would recognize that if the defined tolerance is too great, the actual temperature of the at least semi-molten feedstock will be allowed to stray farther than desired from the target temperature. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
Furthermore, as discussed above, Sato provides the following explicit disclosure:
“The supply of electricity to the heater 185 in step 2 is controlled so as to provide a temperature of 150° C. for a period of time sufficient to substantially complete extraction of the water content of the waste. This control may be made autonomously in the container 18 while receiving feedback from the temperature sensor within the container 18, or while sequentially monitoring output of the temperature sensor by the electrical control panel 8,”
(paragraph [0032]; emphasis added).
This disclosure amounts to an explicit teaching of a control system which is capable of maintaining a single specific temperature within the reactor. A control system which is capable of maintaining a single specific temperature is also necessarily capable of maintaining a temperature within a tolerance of 10 °C of a target temperature. Thus, a person having ordinary skill in the art would have a reasonable expectation that a tolerance of 10 °C from a target temperature is attainable with a control system.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the defined tolerance, such that the defined tolerance is within 10 °C of (i.e. less than or equal to 10 °C from) the target temperature value, in order to obtain a control device which does not allow the actual temperature to stray too far from the target temperature.
Modified Scheirs is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 342 hours or more during a time period of 360 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Scheirs by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 360 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 342 hours or more during a 360 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 3: Modified Scheirs is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 576 hours or more during a time period of 720 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 720 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Scheirs by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 720 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 576 hours or more during a 720 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 4: Modified Scheirs is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 756 hours or more during a time period of 1080 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 1080 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Scheirs by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 1080 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 756 hours or more during a 1080 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 5: Modified Scheirs is silent to the volume of the reactor vessel being between 100 and 20,000 gallons.
However, a person having ordinary skill in the art would recognize that the volume of the reactor is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if the volume of the reactor vessel is too low, it will not be able to process feedstock at a rate required to meet demand. On the other hand, if the volume is too high, the reactor would require an excessive amount of material and capital to construct relative the amount of plastic it is required to process. Furthermore, if the reactor volume is far in excess of the volume of plastic feedstock which will be fed to it per unit time, the functionality of said reactor vessel may be adversely affected due to the plastic level therein being excessively low, e.g. relative the positioning of the heaters 50 and the agitator 40. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the volume of the reactor vessel so that it is between 100 and 20,000 gallons, in order to obtain a reactor which is appropriately sized to meet a particular demand for plastic processing.
With regard to claim 6: Modified Scheirs is silent to the reactor vessel being configured to maintain a pressure between -7.5 and 14.5 psig.
However, a person having ordinary skill in the art would recognize that the pressure within the reactor vessel is a result effective variable in modified Scheirs. In particular, a person having ordinary skill in the art would recognize that the pressure within the reactor 30 will determine which pyrolysis products will vaporize and pass out of the reactor 30 to fractionator 70 and which will remain behind. If the pressure in the reactor is too high, pyrolysis products will undesirably remain in the pyrolysis residue within the reactor 30 as opposed to vaporizing and passing into the fractionator 70. If the pressure in the reactor is too low, heavier pyrolysis products will be allowed to vaporize, which will result in the fractionator 70 receiving heavier than desired pyrolysis products. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the operating pressure of the reactor, such that the reactor vessel is configured to maintain a pressure between -7.5 and 14.5 psig, in order to obtain a system wherein lighter pyrolysis products are able to vaporize and pass to the fractionator while heavier pyrolysis products are prevented from vaporizing and thus remain in the pyrolysis reactor.
With regard to claim 7: Modified Scheirs is silent to the heaters being configured for applying heat to the plastic feedstock at a heat density between 5 and 55 W/in2.
However, a person having ordinary skill in the art would recognize that the heat density (power output per unit surface area) of the heaters is a result effective variable in modified Scheirs. In particular, a person having ordinary skill in the art would recognize that if the heat density of the heaters is too low, then said heaters will be incapable of supplying heat to a discrete amount of plastic feedstock at rates quick enough to effect pyrolysis. On the other hand, if heat density of the heaters is too high, energy will be wasted, and pyrolysis reactions within the reactor may proceed to an extent further than desired. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the heat density of the heaters, such that the heaters are configured to apply heat to the plastic feedstock at a heat density between 5 and 55 W/in2, in order to obtain a heaters which are capable of effecting pyrolysis of the plastic feedstock without wasting energy and/or causing pyrolysis to proceed further than a desired extent.
With regard to claims 8, 10, and 11: The plurality of heaters 50 are an array of electric heaters (FIR heaters) which are vertically oriented and extend into an interior volume of the reactor vessel (Figure 1, paragraph [0045] and [0054]-[0055]).
With regard to claim 9: The plurality of heaters 50 are positioned around (i.e. near) sides (i.e. vertical sidewall(s)) of the reactor vessel (Figure 1, paragraph [0045] and [0054]-[0055]).
With regard to claim 12: The reactor vessel includes an agitator (mixing element) 40 configured for stirring the plastic feedstock during pyrolysis (Figure 1, paragraph [0053]).
With regard to claim 13: The agitator 40 of modified Scheirs is at least capable of operating continuously so as to continuously stir the plastic feedstock within the reactor vessel during pyrolysis. Accordingly, modified Scheirs satisfies the claim language regarding the agitator being configured to continuously stir the plastic feedstock within the reactor vessel during pyrolysis. See MPEP 2114 for guidance.
In the unlikely alternative, it has been established that continuous operation is obvious over a prior art batch process (see MPEP 2144.04(V)E). Furthermore, a person having ordinary skill in the art would recognize that continuous stirring during pyrolysis is advantageous, as such continuous stirring would ensure that material within the reactor is more uniformly heated and pyrolyzed. Accordingly, in the unlikely event that the agitator 40 of modified Scheirs is not capable of continuous stirring, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by configuring the agitator 40 to operate so as to continuously stir the plastic feedstock within the reactor vessel during pyrolysis, in order to obtain a device which is capable of, by virtue of continuous stirring, more uniformly heating and pyrolysing the plastic feedstock.
With regard to claim 14: As discussed in the rejection of claim 13 above, the agitator of Scheirs is capable of continuously stirring the plastic feedstock within the reactor vessel during pyrolysis. Accordingly, it is understood that the agitator is capable of continuously producing average liquid flow velocities within the reactor.
Modified Scheirs is silent to the agitator being configured to continuously produce average liquid flow velocities specifically between 0.2 and 10 m/s.
However, a person having ordinary skill in the art would recognize that the average liquid flow velocity which the agitator is capable of producing is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if said agitator is incapable of inducing an average liquid flow velocity above a particular threshold, it will be incapable of properly stirring the plastic material within the reactor so as to ensure uniform heating and pyrolysis of said plastic material. On the other hand, if the agitator is configured to produce an average liquid flow velocity which is excessively high, it will waste energy by stirring (or attempting to stir) the plastic material at a rate which is greater than is necessary or possible. Furthermore, an agitator which is configured to produce an excessively high average liquid flow velocity will be subjected to greater stresses than one which stirs liquid more slowly. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the rate at which the agitator stirs plastic material within the reactor, i.e. by configuring the agitator to continuously produce average liquid flow velocities between 0.2 and 10 m/s within the reactor, in order to obtain a system wherein the agitator is capable of effectively stirring the plastic material so as to ensure uniform heating and pyrolysis of the plastic material without the agitator wasting energy or subject itself to excessive stress.
With regard to claim 15: As discussed in the rejection of claim 13 above, the agitator of Scheirs is capable of continuously stirring the plastic feedstock within the reactor vessel during pyrolysis. Accordingly, it is understood that the agitator is capable of continuously producing average liquid flow velocities within the reactor.
Modified Scheirs is silent to the agitator being configured to continuously produce average liquid flow velocities specifically between 0.5 and 6 m/s.
However, a person having ordinary skill in the art would recognize that the average liquid flow velocity which the agitator is capable of producing is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if said agitator is incapable of inducing an average liquid flow velocity above a particular threshold, it will be incapable of properly stirring the plastic material within the reactor so as to ensure uniform heating and pyrolysis of said plastic material. On the other hand, if the agitator is configured to produce an average liquid flow velocity which is excessively high, it will waste energy by stirring (or attempting to stir) the plastic material at a rate which is greater than is necessary or possible. Furthermore, an agitator which is configured to produce an excessively high average liquid flow velocity will be subjected to greater stresses than one which stirs liquid more slowly. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by optimizing the rate at which the agitator stirs plastic material within the reactor, i.e. by configuring the agitator to continuously produce average liquid flow velocities between 0.5 and 6 m/s within the reactor, in order to obtain a system wherein the agitator is capable of effectively stirring the plastic material so as to ensure uniform heating and pyrolysis of the plastic material without the agitator wasting energy or subject itself to excessive stress.
With regard to claims 16 and 17: In Figure 1 of Scheirs, the agitator 40 is show as comprising a vertically oriented drive shaft and a plurality of stirring elements each mounted on the drive shaft and comprising a plurality of plurality of blades extending radially outward from the drive shaft (Figure 1, see annotated Figure 1 below).
Scheirs teaches that the agitator 40 may be an “impellor stirrer” (paragraph [0053]). This teaching at least suggests that the stirring elements depicted in Figure 1 (see annotated Figure 1 below) are impellers and that the blades of each of said stirring elements are impeller blades. Accordingly, it would at least be obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by configuring the agitator such that the plurality of stirring elements mounted on the drive shaft are impellers, and such that the plural blades of each of the stirring elements are impeller blades, in order to obtain a system having a predictably functional agitator which is congruent with the suggestions of Scheirs.
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With regard to claim 18: The reactor 30 further comprises at least one vapor outlet configured for directing hydrocarbon vapor generated during pyrolysis out of the reactor vessel, said at least one vapor outlet connecting the reactor vessel to the fractionator 70 (Figure 1, paragraphs [0054] and [0055]).
With regard to claim 21: In modified Scheirs, the plastic feedstock may be supplied by melt mixing device (e.g. an extruder) 20 as a stream molten or semi-molten material (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053] and [0060]). The reactor vessel of pyrolysis reactor 30 is configured to pyrolyze the stream of molten or semi-molten material (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053] and [0060]).
The melt mixing device 20 of modified Scheirs is at least capable of operating continuously so as to supply the plastic feedstock as a continuous stream of molten or semi-molten material. Accordingly, modified Scheirs satisfies the claim language regarding the plastic feedstock being supplied as a continuous stream molten or semi-molten material. See MPEP 2114 for guidance.
In the unlikely alternative, it has been established that continuous operation is obvious over a prior art batch process (see MPEP 2144.04(V)E). Accordingly, in the unlikely event that the melt mixing device of modified Scheirs is not capable of supplying the plastic feedstock as a continuous stream, it would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs by configuring the melt mixing device 20 to operate continuously so as to supply the plastic feedstock as a continuous stream molten or semi-molten material, in order to obtain a device which is predictably capable of continuous operation.
With regard to claim 24: Modified Scheirs remains silent to the one or more temperature sensors being arranged vertically.
However, Inoue teaches temperature sensor (temperature measuring device) 8 which is vertically arranged, said temperature sensor being provided for measuring the temperature of melted plastic within a reactor vessel 3 (Figure 1, Column 6 Lines 15-55). In view of Inoue, a person having ordinary skill in the art would recognize that a vertically arranged temperature sensor is suitable for use in the system of Scheirs.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Inoue by arranging the at least one temperature sensor vertically, in order to obtain a system having a predictably functional temperature sensor.
Claim(s) 23-25 is/are rejected under 35 U.S.C. 103 as being unpatentable over Scheirs in view of Maezawa, Van Meirhaeghe, Griffin, and Inoue as applied to claims 1, 2, and 26 above, and in further view of Winters (US 2,246,563).
With regard to claims 23-25: Scheirs is silent to the one or more temperature sensors being arranged along an internal wall of the reactor; the one or more temperature sensors being arranged vertically; and pyrolysis control system being configured for: at least temporarily storing a target liquid bath level for the liquid bath in the reactor vessel; monitoring a liquid bath level inside the reactor as measured by the one or more temperature sensors; and in response to the liquid bath level measured by the one or more temperature sensors, controlling feedstock input and/or product output to maintain the liquid bath level inside the reactor within a defined tolerance relative to the target liquid bath level.
However, level control systems which determine liquid level using a plurality of temperature sensors arranged along an internal wall of a vessel are known in the art. For example, Winters teaches a system comprising: a vessel 1; a temperature sensor (thermocouple) 5 arranged along an internal wall of the vessel; and a control system configured for: at least temporarily storing a target liquid level for the liquid in the vessel 1, monitoring a liquid level inside the vessel 1 as measured by the one or more temperature sensors 5, and controlling liquid output to maintain the liquid level in the vessel 1 within a defined tolerance relative the target level (Figure 1, Page 1 Left column Line 49-page 2 left column line 51, especially page 1 right column lines 35-60).
Winters teaches that a level control system of this type is “is more positive and accurate than float type controllers, particularly as applied to controlling the liquid level in vessels handling heated hydrocarbons comprising heavy oils which tend to deposit coke,” (Page 2 Left column lines 47-52). A person having ordinary skill in the art would recognize that said advantages are applicable to the flow of liquid level in pyrolysis reactors holding molten plastic, like the reactor of Scheirs, as molten plastic is a heated heavy organic liquid which will tend to deposit coke when undergoing pyrolysis. Furthermore, a person having ordinary skill in the art would recognize that some plastics, e.g. polyethylene, polypropylene, polystyrene, etc., are hydrocarbons.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Winters by configuring the one or more temperature sensor to be arranged along an internal wall of the reactor, and by further configuring the pyrolysis control to: at least temporarily storing a target liquid bath level for the liquid bath in the reactor vessel; monitoring a liquid bath level inside the reactor as measured by the one or more temperature sensors; and in response to the liquid bath level measured by the one or more temperature sensors, controlling product output to maintain the liquid bath level inside the reactor within a defined tolerance relative to the target liquid bath level, in order to provide the system of Scheirs with a means of controlling the level of the plastic feedstock within the reactor vessel, said means being more positive and accurate than a float type controller.
Modified Scheirs remains silent to the one or more temperature sensors being arranged vertically.
However, Winters teaches an additional embodiment wherein the vessel 20 has a plurality of temperature sensors (thermocouples) P1-P7 arranged vertically, i.e. in a vertical line, along an internal wall of the vessel (Figure 2, Page 2 Left Column Line 53-Page 2 Right Column Line 75). A person having ordinary skill in the art would recognize that, if a vessel provided with a control system for monitoring and controlling liquid level using one or more temperature sensors is provided with a plurality of temperature sensors arranged vertically, i.e. in a vertical line, along an internal wall of the vessel, then the control system would be capable of more accurately determining liquid level in the vessel across a wider array of potential liquid levels, in comparison to a similar system having only one temperature sensor.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Winters by configuring the one or more temperature sensor to be a plurality of temperature sensors arranged vertically, i.e. in a vertical line, along an internal wall of the reactor, in order to obtain a system which is capable of more accurately determining liquid level in the vessel across a wider array of potential liquid levels, in comparison to a similar system having only one temperature sensor.
Claim(s) 1-9, 12-15, 18, 21, 24, and 26 is/are rejected under 35 U.S.C. 103 as being unpatentable over Van Meirhaeghe in view of Griffin and Inoue.
With regard to claims 1, 2, and 26: Van Meirhaeghe teaches a system for pyrolyzing plastic feedstock comprising post- consumer and/or post-industrial plastics (abstract, Figure 1, Column 15 Line 65-Column 17 Line 30), the system comprising:
At least one extruder 200 configured for melting the plastic feedstock (Figure 1, Column 15 Line 65-Column 17 Line 30).
Wherein the at least one extruder 200 comprising at least one extruder heater (external heat source; not shown) (Column 16 Lines 20-30), the at least one extruder heater configured for heating the plastic feedstock in the extruder barrel to a temperature of higher than 330 °C, e.g. a temperature of 350 °C, or more to produce at least semi-molten feedstock (Figure 1, Column 11 Lines 15-30, Column 20 Lines 1-21).
A reactor comprising:
A reactor vessel 101 defining an internal volume configured for receiving the at least semi-molten feedstock from the at least one extruder 200 and pyrolyzing the at least semi-molten feedstock (Figure 1, Column 15 Line 65-Column 17 Line 50).
And at least one reactor heater 112 configured for heating the feedstock in the reactor vessel's internal volume to a temperature greater than 350 °C, e.g. a temperature of 420 °C or 500 °C (Column 13 Lines 30-36 and 57-64, Column 20 Lines 42-55).
Van Meirhaeghe is silent to one or more temperature sensors configured for sensing the temperature of the at least semi-molten feedstock in the reactor vessel; and a pyrolysis control system configured for: at least temporarily storing a target temperature value for the at least semi-molten feedstock in the reactor vessel, monitoring the temperature of the at least semi-molten feedstock in the reactor vessel as measured by the one or more temperature sensors, and in response to the temperature measured by the one or more temperature sensors, controlling the one or more heaters to maintain the temperature of the at least semi-molten feedstock within a defined tolerance relative to the target temperature value, wherein the pyrolysis control system is configured as a feedback loop or a feedforward loop.
However, temperature control systems which maintain pyrolysis reactors at a target temperature are known in the art. For example, Griffin teaches a pyrolysis system comprising a reactor vessel 300, at least one temperature sensor (thermocouple probe) 505 configured for sensing the temperature within the reactor vessel 300, and a pyrolysis control system comprised of thermocouple reader 510 and throttle controller 515, the pyrolysis control system configured for: at least temporarily storing a target temperature value for the reactor vessel 300, monitoring the temperature in the reactor vessel as measured by the at least one temperature sensor 505, and in response to the temperature measured by the at least one temperature sensor, controlling one or more heaters (burners) 400 to maintain the temperature of the at least semi-molten feedstock above and below predetermined thresholds, wherein the control system is configured as feedback loop, i.e. a thermocouple feedback loop 500 (Figure 10, Column 11 Lines 34-60). Griffin expressly teaches that “The thermocouple feedback loop 500 automatically maintains the target temperature within the reactor 300,” (Column 11 Lines 37-39). When this teaching regarding maintaining of target temperature is considered in combination with the teaching(s) to predetermined temperature thresholds (Column 11 Lines 48-59), it would at least suggest that said predetermined temperature thresholds are temperatures corresponding to a defined tolerance from a target temperature value.
The benefits of including such a temperature control system would be clear to one of ordinary skill in the art. Namely, a person having ordinary skill in the art would recognize that such a temperature control system can automatically maintain a pyrolysis reactor vessel at a range of temperatures necessary for pyrolysis.
As for temperature control systems which directly measure the temperature of molten plastic feedstocks, these too are known in the art. For example, Inoue teaches a plastic pyrolysis system comprising: a reactor vessel (pyrolysis vessel) 3 configured for pyrolyzing a plastic feedstock in a molten state, at least one temperature sensor (temperature measuring device) 8 provided for measuring the temperature of melted plastic within the reactor vessel 3 (indeed the temperature sensor 8 is illustrated as being in direct contact with the melted plastic within the vessel 3), and a pyrolysis control system comprised of temperature recorder 9 and temperature regulator (Figure 1, Column 6 Lines 15-55). It is implicit that a temperature control system which operates based on temperature measurements taken directly from a pyrolysis feedstock within a reactor will be capable of controlling the temperature of the pyrolysis feedstock itself (as opposed to a temperature of the reactor vessel).
In Van Meirhaeghe, the reactor vessel 101 pyrolyzes plastic feedstock in a molten state 502 (Figure 3, Column 18 Line 65-Column 19 Line 10). Thus, it would be clear to one of ordinary skill in the art would recognize that a temperature control system which directly measures and thereby controls the temperature of molten plastic within a pyrolysis reactor vessel is particularly suitable for use in a system like that of Van Meirhaeghe.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe in view of Griffin and Inoue by adding one or more temperature sensors configured for sensing the temperature of the at least semi-molten feedstock in the reactor vessel; and a pyrolysis control system configured for: at least temporarily storing a target temperature value for the at least semi-molten feedstock in the reactor vessel, monitoring the temperature of the at least semi-molten feedstock in the reactor vessel as measured by the one or more temperature sensors, and in response to the temperature measured by the one or more temperature sensors, controlling the one or more heaters to maintain the temperature of the at least semi-molten feedstock within a defined tolerance relative to the target temperature value, wherein the pyrolysis control system is configured as a feedback loop, in order to obtain a system that is capable of automatically maintaining the temperature of the at least semi-molten feedstock within the reactor at a desired temperature.
Modified Van Meirhaeghe is silent to the defined tolerance being within 10 °C of the target temperature value.
However, a person having ordinary skill in the art would recognize that the magnitude of the defined tolerance is a result effective variable in the temperature control. In other words, a person having ordinary skill in the art would recognize that if the defined tolerance is too great, the actual temperature of the at least semi-molten feedstock will be allowed to stray farther than desired from the target temperature. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe by optimizing the defined tolerance, such that the defined tolerance is within 10 °C of (i.e. less than or equal to 10 °C from) the target temperature value, in order to obtain a control device which does not allow the actual temperature to stray too far from the target temperature.
Modified Van Meirhaeghe is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 342 hours or more during a time period of 360 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Van Meirhaeghe by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 360 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 342 hours or more during a 360 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 3: Modified Van Meirhaeghe is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 576 hours or more during a time period of 720 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 720 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Van Meirhaeghe by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 720 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 576 hours or more during a 720 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 4: Modified Van Meirhaeghe is silent to the reactor being configured to operate to pyrolyze the plastic feedstock for a cumulative period of 756 hours or more during a time period of 1080 hours.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 1080 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art to modify Van Meirhaeghe by optimizing the cumulative period of time for which the reactor is configured to operate to pyrolyze the plastic feedstock in a 1080 hour period, i.e. such that the reactor is capable of operating to pyrolyze plastic feedstock for a cumulative total of 756 hours or more during a 1080 hour period, in order to obtain a system which is capable of operating with minimal downtime so as to produce a large amount of pyrolysis product in a time efficient manner.
With regard to claim 5: Modified Van Meirhaeghe is silent to the volume of the reactor vessel being between 100 and 20,000 gallons.
However, a person having ordinary skill in the art would recognize that the volume of the reactor is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if the volume of the reactor vessel is too low, it will not be able to process feedstock at a rate required to meet demand. On the other hand, if the volume is too high, the reactor would require an excessive amount of material and capital to construct relative the amount of plastic it is required to process. Furthermore, if the reactor volume is far in excess of the volume of plastic feedstock which will be fed to it per unit time, the functionality of said reactor vessel may be adversely affected due to the plastic level therein being excessively low. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe by optimizing the volume of the reactor vessel so that it is between 100 and 20,000 gallons, in order to obtain a reactor which is appropriately sized to meet a particular demand for plastic processing.
With regard to claim 6: Modified Van Meirhaeghe is silent to the reactor vessel being configured to maintain a pressure between -7.5 and 14.5 psig.
However, a person having ordinary skill in the art would recognize that the pressure within the reactor vessel is a result effective variable in modified Van Meirhaeghe. Van Meirhaeghe indicates as much by the teaching that “the reactor pressure is a value between 1 bar and 10 bar,” (column 10 Lines 49-50). "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
Furthermore, it is noted that the claimed reactor pressure range overlaps the taught reactor pressure range. “In the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists,” (MPEP 2144.05 I).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe by optimizing the operating pressure of the reactor, such that the reactor vessel is configured to maintain a pressure between -7.5 and 14.5 psig, in order to obtain a system wherein lighter pyrolysis products are able to vaporize and pass to the fractionator while heavier pyrolysis products are prevented from vaporizing and thus remain in the pyrolysis reactor.
With regard to claim 7: Modified Van Meirhaeghe is silent to the heaters being configured for applying heat to the plastic feedstock at a heat density between 5 and 55 W/in2.
However, a person having ordinary skill in the art would recognize that the heat density (power output per unit surface area) of the heaters is a result effective variable in modified Van Meirhaeghe. In particular, a person having ordinary skill in the art would recognize that if the heat density of the heaters is too low, then said heaters will be incapable of supplying heat to a discrete amount of plastic feedstock at rates quick enough to effect pyrolysis. On the other hand, if heat density of the heaters is too high, energy will be wasted, and pyrolysis reactions within the reactor may proceed to an extent further than desired. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe by optimizing the heat density of the heaters, such that the heaters are configured to apply heat to the plastic feedstock at a heat density between 5 and 55 W/in2, in order to obtain a heaters which are capable of effecting pyrolysis of the plastic feedstock without wasting energy and/or causing pyrolysis to proceed further than a desired extent.
With regard to claims 8 and 9: The at least one reactor heater 112 is at least one electric heater positioned around sides of the reactor vessel (Van Meirhaeghe: Figure 1, Column 16 Lines 50-52).
With regard to claims 12 and 13: The reactor vessel includes an agitator (mixer/mixing arrangement) 105 for stirring the plastic feedstock during pyrolysis (Van Meirhaeghe: Figure 1, Column 16 Lines 43-68), wherein the agitator 105 is configured to continuously stir the feedstock within the reactor vessel during pyrolysis (Van Meirhaeghe: Column 19 Lines 54-55).
With regard to claim 14: The reactor vessel includes an agitator (mixer/mixing arrangement) 105 for stirring the plastic feedstock during pyrolysis (Van Meirhaeghe: Figure 1, Column 16 Lines 43-68), wherein the agitator 105 is configured to continuously stir the feedstock within the reactor vessel during pyrolysis (Van Meirhaeghe: Column 19 Lines 54-55).
Modified Van Meirhaeghe is silent to the agitator being configured to continuously produce average liquid flow velocities specifically between 0.2 and 10 m/s.
However, a person having ordinary skill in the art would recognize that the average liquid flow velocity which the agitator is capable of producing is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if said agitator is incapable of inducing an average liquid flow velocity above a particular threshold, it will be incapable of properly stirring the plastic material within the reactor so as to ensure uniform heating and pyrolysis of said plastic material. On the other hand, if the agitator is configured to produce an average liquid flow velocity which is excessively high, it will waste energy by stirring (or attempting to stir) the plastic material at a rate which is greater than is necessary or possible. Furthermore, an agitator which is configured to produce an excessively high average liquid flow velocity will be subjected to greater stresses than one which stirs liquid more slowly. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe by optimizing the rate at which the agitator stirs plastic material within the reactor, i.e. by configuring the agitator to continuously produce average liquid flow velocities between 0.2 and 10 m/s within the reactor, in order to obtain a system wherein the agitator is capable of effectively stirring the plastic material so as to ensure uniform heating and pyrolysis of the plastic material without the agitator wasting energy or subject itself to excessive stress.
With regard to claim 15: The reactor vessel includes an agitator (mixer/mixing arrangement) 105 for stirring the plastic feedstock during pyrolysis (Van Meirhaeghe: Figure 1, Column 16 Lines 43-68), wherein the agitator 105 is configured to continuously stir the feedstock within the reactor vessel during pyrolysis (Van Meirhaeghe: Column 19 Lines 54-55).
Modified Van Meirhaeghe is silent to the agitator being configured to continuously produce average liquid flow velocities specifically between 0.5 and 6 m/s.
However, a person having ordinary skill in the art would recognize that the average liquid flow velocity which the agitator is capable of producing is a result effective variable. In particular, a person having ordinary skill in the art would recognize that if said agitator is incapable of inducing an average liquid flow velocity above a particular threshold, it will be incapable of properly stirring the plastic material within the reactor so as to ensure uniform heating and pyrolysis of said plastic material. On the other hand, if the agitator is configured to produce an average liquid flow velocity which is excessively high, it will waste energy by stirring (or attempting to stir) the plastic material at a rate which is greater than is necessary or possible. Furthermore, an agitator which is configured to produce an excessively high average liquid flow velocity will be subjected to greater stresses than one which stirs liquid more slowly. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe by optimizing the rate at which the agitator stirs plastic material within the reactor, i.e. by configuring the agitator to continuously produce average liquid flow velocities between 0.5 and 6 m/s within the reactor, in order to obtain a system wherein the agitator is capable of effectively stirring the plastic material so as to ensure uniform heating and pyrolysis of the plastic material without the agitator wasting energy or subject itself to excessive stress.
With regard to claim 18: The reactor further comprises one or more vapor outlets 107 configured for directing hydrocarbon vapor generated during pyrolysis out of the reactor vessel (Van Meirhaeghe: Figure 1, Column 17 Lines 1-30).
With regard to claim 21: The system of Van Meirhaeghe is capable of operating in a continuous mode such that: i) the extruder will supply a continuous stream of the at least semi-molten feedstock into the reactor vessel, and ii) the reactor vessel will pyrolyze said continuous stream (Van Meirhaeghe: Column 12 Line 45-Column 13 Line 10, Column 20 Lines 22-41).
With regard to claim 24: Modified Scheirs remains silent to the one or more temperature sensors being arranged vertically.
However, Inoue teaches temperature sensor (temperature measuring device) 8 which is vertically arranged, said temperature sensor being provided for measuring the temperature of melted plastic within a reactor vessel 3 (Figure 1, Column 6 Lines 15-55). In view of Inoue, a person having ordinary skill in the art would recognize that a vertically arranged temperature sensor is suitable for use in the system of Scheirs.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Inoue by arranging the at least one temperature sensor vertically, in order to obtain a system having a predictably functional temperature sensor.
Claim(s) 10 and 11 is/are rejected under 35 U.S.C. 103 as being unpatentable over Van Meirhaeghe in view of Griffin and Inoue as applied to claims 1, 2, and 26 above, and in further view of Scheirs.
With regard to claims 10 and 11: Modified Van Meirhaeghe is silent to an array of electric heaters that are vertically oriented and extend into the internal volume of the reactor vessel.
Scheirs teaches a system for pyrolyzing plastic feedstock comprising post-consumer and/or post- industrial plastics (abstract, Figure 1, paragraphs [0053]-[0061]), the system comprising: at least one energy transfer apparatus configured for receiving the plastic feedstock and applying energy to the plastic feedstock, wherein the at least one energy transfer apparatus comprises an extruder (melt mixing device) 20 configured for melting the plastic feedstock and a pyrolysis reactor 30 configured for pyrolyzing the plastic feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053], [0054], and [0060]).
Said pyrolysis reactor 30 comprises: a reactor vessel defining an internal volume configured for receiving the at least semi-molten feedstock from the at least one extruder 20 and pyrolyzing the at least semi-molten feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053], [0054], and [0060]); and a plurality of heaters 50 configured for heating the feedstock in the reactor vessel's internal volume to a temperature ranging from 360°C to 450°C (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053], [0054], and [0060]).
The plurality of heaters 50 are an array of electric heaters (FIR heaters) which are vertically oriented and extend into an interior volume of the reactor vessel (Figure 1, paragraph [0045] and [0054]-[0055]).
It is well established that it would be obvious to substitute one known prior art element for another in order to obtain predictable results (MPEP 2143).
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe in view of Scheirs by substituting the pyrolysis reactor of Scheirs for that of Van Meirhaeghe, in order to obtain a system having a predictably functional pyrolysis reactor comprising an array of electric heaters (FIR heaters) which are vertically oriented and extend into an interior volume of the reactor vessel.
Claim(s) 16 and 17 is/are rejected under 35 U.S.C. 103 as being unpatentable over Van Meirhaeghe in view of Griffin and Inoue as applied to claim 12 above, and in further view of Scheirs.
With regard to claims 16 and 17: Modified Van Meirhaeghe is silent to the agitator comprising a vertically oriented drive shaft and one or more impellers mounted on the drive shaft, wherein the one or more impellers each comprise a plurality of impeller blades extending radially outwardly from the drive shaft.
Scheirs teaches a system for pyrolyzing plastic feedstock comprising post-consumer and/or post- industrial plastics (abstract, Figure 1, paragraphs [0053]-[0061]), the system comprising: at least one energy transfer apparatus configured for receiving the plastic feedstock and applying energy to the plastic feedstock, wherein the at least one energy transfer apparatus comprises an extruder (melt mixing device) 20 configured for melting the plastic feedstock and a pyrolysis reactor 30 configured for pyrolyzing the plastic feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053], [0054], and [0060]).
Said pyrolysis reactor 30 comprises: a reactor vessel defining an internal volume configured for receiving the at least semi-molten feedstock from the at least one extruder 20 and pyrolyzing the at least semi-molten feedstock (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053], [0054], and [0060]); and a plurality of heaters 50 configured for heating the feedstock in the reactor vessel's internal volume to a temperature ranging from 360°C to 450°C (Figure 1, paragraphs [0053]-[0061], especially paragraphs [0053], [0054], and [0060]).
The reactor vessel includes an agitator (mixing element) 40 configured for stirring the plastic feedstock during pyrolysis (Scheirs: Figure 1, paragraph [0053]). The agitator 40 is shown as comprising a vertically oriented drive shaft and a plurality of stirring elements each mounted on the drive shaft and comprising a plurality of plurality of blades extending radially outward from the drive shaft (Figure 1, see annotated Figure 1 below).
Scheirs teaches that the agitator 40 may be an “impellor stirrer” (paragraph [0053]). This teaching at least suggests that the stirring elements depicted in Figure 1 (see annotated Figure 1 below) are impellers and that the blades of each of said stirring elements are impeller blades.
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It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe in view of Scheirs by substituting the pyrolysis reactor of Scheirs for that of Van Meirhaeghe in order to obtain a system having a predictably functional pyrolysis reactor comprising an agitator configured to stir the feedstock within the reactor vessel during pyrolysis, said agitator comprising a vertically oriented drive shaft and one or more impellers mounted on the drive shaft, wherein the one or more impellers each comprise a plurality of impeller blades extending radially outwardly from the drive shaft.
Claim(s) 23-25 is/are rejected under 35 U.S.C. 103 as being unpatentable over Van Meirhaeghe in view of Griffin and Inoue as applied to claims 1, 2, and 26 above, and in further view of Winters (US 2,246,563).
With regard to claims 23-25: Van Meirhaeghe is silent to the one or more temperature sensors being arranged along an internal wall of the reactor; the one or more temperature sensors being arranged vertically; and pyrolysis control system being configured for: at least temporarily storing a target liquid bath level for the liquid bath in the reactor vessel; monitoring a liquid bath level inside the reactor as measured by the one or more temperature sensors; and in response to the liquid bath level measured by the one or more temperature sensors, controlling feedstock input and/or product output to maintain the liquid bath level inside the reactor within a defined tolerance relative to the target liquid bath level.
However, level control systems which determine liquid level using a plurality of temperature sensors arranged along an internal wall of a vessel are known in the art. For example, Winters teaches a system comprising: a vessel 1; a temperature sensor (thermocouple) 5 arranged along an internal wall of the vessel; and a control system configured for: at least temporarily storing a target liquid level for the liquid in the vessel 1, monitoring a liquid level inside the vessel 1 as measured by the one or more temperature sensors 5, and controlling liquid output to maintain the liquid level in the vessel 1 within a defined tolerance relative the target level (Figure 1, Page 1 Left column Line 49-page 2 left column line 51, especially page 1 right column lines 35-60).
Winters teaches that a level control system of this type is “is more positive and accurate than float type controllers, particularly as applied to controlling the liquid level in vessels handling heated hydrocarbons comprising heavy oils which tend to deposit coke,” (Page 2 Left column lines 47-52). A person having ordinary skill in the art would recognize that said advantages are applicable to the flow of liquid level in pyrolysis reactors holding molten plastic, like the reactor of Scheirs, as molten plastic is a heated heavy organic liquid which will tend to deposit coke when undergoing pyrolysis. Furthermore, a person having ordinary skill in the art would recognize that some plastics, e.g. polyethylene, polypropylene, polystyrene, etc., are hydrocarbons.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Van Meirhaeghe in view of Winters by configuring the one or more temperature sensor to be arranged along an internal wall of the reactor, and by further configuring the pyrolysis control to: at least temporarily storing a target liquid bath level for the liquid bath in the reactor vessel; monitoring a liquid bath level inside the reactor as measured by the one or more temperature sensors; and in response to the liquid bath level measured by the one or more temperature sensors, controlling product output to maintain the liquid bath level inside the reactor within a defined tolerance relative to the target liquid bath level, in order to provide the system of Scheirs with a means of controlling the level of the plastic feedstock within the reactor vessel, said means being more positive and accurate than a float type controller.
Modified Scheirs remains silent to the one or more temperature sensors being arranged vertically.
However, Winters teaches an additional embodiment wherein the vessel 20 has a plurality of temperature sensors (thermocouples) P1-P7 arranged vertically, i.e. in a vertical line, along an internal wall of the vessel (Figure 2, Page 2 Left Column Line 53-Page 2 Right Column Line 75). A person having ordinary skill in the art would recognize that, if a vessel provided with a control system for monitoring and controlling liquid level using one or more temperature sensors is provided with a plurality of temperature sensors arranged vertically, i.e. in a vertical line, along an internal wall of the vessel, then the control system would be capable of more accurately determining liquid level in the vessel across a wider array of potential liquid levels, in comparison to a similar system having only one temperature sensor.
It would have been obvious to one of ordinary skill in the art before the effective filing date to further modify Scheirs in view of Winters by configuring the one or more temperature sensor to be a plurality of temperature sensors arranged vertically, i.e. in a vertical line, along an internal wall of the reactor, in order to obtain a system which is capable of more accurately determining liquid level in the vessel across a wider array of potential liquid levels, in comparison to a similar system having only one temperature sensor.
The following rejections are maintained from the previous Office Action.
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
Claims 1-18, 21, and 23-26 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over the claims of copending Application No. 19/006,116 (reference application).
Although the claims at issue are not identical, they are not patentably distinct from each other because they are drawn to a nearly identical system for the pyrolysis of plastics. The principal difference between the present claims and those of the ‘116 application, is that the present claims require that the reactor is configured to operate for a certain cumulative amount of time in a 360 hour period.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
Accordingly, to one of ordinary skill in the art, the claims of the ‘116 application would suggest the claims of the present application wherein the plastic pyrolysis system is required to be capable of operating for a certain cumulative time in a 360 hour period.
This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
Claims 1-18, 21, and 23-26 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over the claims of copending Application No. 19/006,093 (reference application).
Although the claims at issue are not identical, they are not patentably distinct from each other because they are drawn to a nearly identical system for the pyrolysis of plastics. The principal difference between the present claims and those of the ‘093 application, is that the present claims require that the reactor is configured to operate for a certain cumulative amount of time in a 360 hour period.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
Accordingly, to one of ordinary skill in the art, the claims of the ‘093 application would suggest the claims of the present application wherein the plastic pyrolysis system is required to be capable of operating for a certain cumulative time in a 360 hour period.
This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
Claims 1-18, 21, and 23-26 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over the claims of copending Application No. 19/006,106 (reference application).
Although the claims at issue are not identical, they are not patentably distinct from each other because they are drawn to a nearly identical system for the pyrolysis of plastics. The principal difference between the present claims and those of the ‘106 application, is that the present claims require that the reactor is configured to operate for a certain cumulative amount of time in a 360 hour period.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
Accordingly, to one of ordinary skill in the art, the claims of the ‘106 application would suggest the claims of the present application wherein the plastic pyrolysis system is required to be capable of operating for a certain cumulative time in a 360 hour period.
This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
Claims 1-18, 21, and 23-26 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over the claims of copending Application No. 19/006,107 (reference application).
Although the claims at issue are not identical, they are not patentably distinct from each other because they are drawn to a nearly identical system for the pyrolysis of plastics. The principal difference between the present claims and those of the ‘107 application, is that the present claims require that the reactor is configured to operate for a certain cumulative amount of time in a 360 hour period.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
Accordingly, to one of ordinary skill in the art, the claims of the ‘107 application would suggest the claims of the present application wherein the plastic pyrolysis system is required to be capable of operating for a certain cumulative time in a 360 hour period.
This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
Claims 1-30 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over the claims of copending Application No. 19/294,862 (reference application).
Although the claims at issue are not identical, they are not patentably distinct from each other because they are drawn to a nearly identical system for the pyrolysis of plastics. The principal difference between the present claims and those of the ‘862 application, is that the present claims require that the reactor is configured to operate for a certain cumulative amount of time in a 360 hour period.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
Accordingly, to one of ordinary skill in the art, the claims of the ‘862 application would suggest the claims of the present application wherein the plastic pyrolysis system is required to be capable of operating for a certain cumulative time in a 360 hour period.
This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
Claims 1-18, 21, and 26 rejected on the ground of nonstatutory double patenting as being unpatentable over the claims of U.S. Patent No. 12,410,370.
Although the claims at issue are not identical, they are not patentably distinct from each other because they are drawn to a nearly identical system for the pyrolysis of plastics. The principal difference between the present claims and those of the ‘370 patent, is that the present claims require that the reactor is configured to operate for a certain cumulative amount of time in a 360 hour period.
However, a person having ordinary skill in the art would recognize that the cumulative amount of time for which a system is capable of operating in a 360 hour period is a result effective variable. To elaborate, it is well understood that the less downtime a system can be operated with, the better, as less downtime will ultimately lead to greater and more time efficient production of product. "[When] the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation," (see MPEP 2144.05 II A).
Accordingly, to one of ordinary skill in the art, the claims of the ‘370 patent would suggest the claims of the present application wherein the plastic pyrolysis system is required to be capable of operating for a certain cumulative time in a 360 hour period.
Citation of Pertinent Prior Art
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 2023/0265348 is the PG pub corresponding to the Van Meirhaeghe patent relied upon in the 103 rejections above.
Conclusion
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/JONATHAN LUKE PILCHER/Examiner, Art Unit 1772
1 i.e. the 103 rejections made over Scheirs in view of Maezawa, Van Meirhaeghe, Griffin, and Inoue
Prosecution Insights