DETAILED ACTION
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Status
Claims 1-4 and 7 are amended.
The amendments to claims 1 and 7 overcome the previous claim objections. The amendments to claims 2 and 3 overcome the previous112(b) rejections.
Claims 1-18 are pending for examination below.
Response to Arguments
Applicant's arguments filed 18 September 2025 have been fully considered but they are not persuasive.
Applicant argues on pages 8-11 of the Remarks that the instant specification explains the differences between the claimed preheating of combustion air with feed water as compared to the preheating of combustion air with steam of Wells. It is further argued that the instant specification provides evidence that preheating the combustion air with feed water as claimed, rather than steam as in Wells, provides benefits of reduced fuel consumption, reduced flue gas exit temperature, and relatively unchanged construction costs. Thus, it is argued that the use of feed water, rather than steam, is inventive and not merely a different phase of water as proposed by the Examiner.
In response, while the instant specification does discuss the difference in temperature of the resulting flue gas after cooling with water as opposed to steam in paragraph [0035], this paragraph does not discuss any specific evidence that the preheating with water versus steam provides the additional cooling of flue gas discussed. The Tables in the instant specification do appear to show that, for particular conditions, the use of water provides improved results in the temperature of the flue gas over the use of steam. However, these results are not clear as to the conditions used to achieve the improved results. The instant specification recites that some of the Examples are steam or super-heated steam and some are feed water, but it is not clear what temperature and pressure is used for the water and the steam. Thus, there is no evidence that the improved results would be true for the entire scope of claim 1, which is not limited to any particular temperature or pressure. Further, it is not clear that the results would be improved over Wells, as no comparison can be made as to the steam of Wells being the same or different temperature and/or pressure than the water and/or steam of the Examples in the Table of the instant specification. As such, the Table and the remaining Examples in the instant specification are not sufficient to provide evidence of unexpected results, and the rejection over Wells is maintained.
While the arguments are not persuasive, upon further consideration, a new ground(s) of rejection is made in view of newly discovered 112(b) issues. The rejection below has been made Non-Final.
Claim Objections
Claims 2 and 7 are objected to because of the following informalities:
With regard to claim 2, the claim recites in line 1 “the steam generated from the feed water”. For consistency this should be “the steam produced from the feed water”.
With regard to claim 7, the claim recites in line 4 “to obtain the superheated high-pressure…steam”. However, superheated high-pressure steam is not recited until claim 2. Thus, the term “the superheated” lacks antecedent basis. Claim 7 should either be amended to recite only “to obtain superheated” or to depend from claim 2.
Appropriate corrections are required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-13 and 15-18 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
With regard to claim 1, the claim has the following issues:
(i) the preamble recites “a method for reacting one or more hydrocarbons by steam cracking”, but there is no further recitation of “steam cracking” as a process step within the claim. The only mention of steam is the recitation that steam is “produced from feed water”, but that steam is never indicated as used within the process. Thus, it is unclear how the process includes steam cracking, and the claim is indefinite.
(ii) the recitation that “steam is produced from feed water” lacks a clear nexus with the rest of the claim. There are no further specifics as to how the steam is produced, and the steam is never used within the process. Further, it is not clear from the wording of the claim if the steam is produced from the preheating of the feed water or is produced in a further step from the preheated feed water. Thus, it is unclear why steam is produced or how it is produced, and the claim is indefinite.
(iii) the last lines recite “the combustion air preheating is carried out at least in part and/or at least sometimes using heat withdrawn from…the feed water upstream of the feed water preheating.” The term “sometimes” is a relative term which renders the claim indefinite. The term “sometimes” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. The instant specification does not provide any information regarding the term “sometimes”, which is only present in the claims as originally filed. Thus, there is no way to determine the metes and bounds of the frequency of the preheating, and the claim is indefinite.
For purposes of examination, the following interpretations will be used:
(i) the input streams which are conducted through the radiant zone are being steam cracked within (instant specification [0030]);
(ii) the steam is produced only after the claimed preheating step (see instant claim 7), and also that the steam which is produced from feed water is then used as the steam for the steam cracking in the radiant zone (instant specification [0040]); and
(iii) the broadest reasonable interpretation of “sometimes using heat withdrawn from…the feed water” is that there are two options for the preheating, a) times where heat withdrawn from the feed water is used for the combustion air preheating and b) times where heat withdrawn from the feed water is not used for the combustion air preheating. Using this interpretation, a reference which preheats the combustion air using steam or other heating would meet the claimed limitations during the “sometimes” that are equivalent to option b).
With regard to claim 7, the claim recites “in which the feed water preheating is performed in one or more flue gas channels in the at least one convection zone, wherein the feed water preheating is performed at a lower temperature level than for steam superheating to obtain the superheated high-pressure or super-high-pressure steam, and for a process steam superheating to provide sufficiently heated process steam which is used to form the one or more input streams.” It is unclear what is meant by the last phrase “and for a process steam superheating to provide sufficiently heated process steam which is used to form the one or more input streams”, because it is unclear whether this is connected to the “wherein the feed water preheating is performed at a lower temperature” clause above, or instead connects back to the “feed water preheating” at the beginning of the claim. Thus, the claim is indefinite.
For purposes of examination, the Examiner will consider that the claim is stating that the preheating is at a temperature which is both i) lower than a temperature which would provide steam superheating to obtain superheated high pressure steam and ii) lower than a temperature which would provide sufficiently superheated process steam for the one or more input streams.
With regard to claims 2-6, 8-13, and 15-18, the claims are rejected as being dependent on a rejected base claim.
Claim Language Suggestion
The Examiner suggests the following language to overcome the above issues and increase the clarity of claim 1. The use of the following phrasing in any amendments is entirely optional, but is meant to help provide a path toward allowance.
1. A method for reacting one or more hydrocarbons by steam cracking, comprising:
preheating combustion air at least in part by heat exchange with feed water;
preheating the feed water downstream of the heat exchange in at least one convection zone of at least one cracker furnace to produce preheated feed water;
producing steam from the preheated feed water;
firing heating gas with the preheated combustion air to heat at least one radiant zone of the at least one cracker furnace; and
steam cracking at least one input stream containing the one or more hydrocarbons and the steam in the at least one radiant zone to obtain at least one product stream.
Claim Rejections - 35 USC § 103
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.
Claims 1-5, 7-10, and 12-18 are rejected under 35 U.S.C. 103 as being unpatentable over Wells et al. (US 4,617,109).
With regard to claim 1, Wells teaches a method for steam cracking (column 1, lines 6-8) comprising the following steps (see Figure and corresponding description columns 3-4):
a) providing a hydrocarbon feed stream 23 to a radiant section comprising cracking tubes 6 in steam cracking furnace 1 to produce a cracked product gas which is passed to manifold 20 (column 3, lines 4-7 and 31-32).
b) heating the radiant section by heating combustion air in fuel burners 5 (firing heating gas with combustion air) (column 3, lines 42-44).
c) passing water from a condensate receiver 27 to feedwater heating coil 7 in the upper part of the convection section to produce steam (feed water preheating) (column 3, lines 50-52).
d) preheating the combustion air in steam coils 14 to 17 to produce a heated combustion air (column 3, lines 39-42).
d) passing low pressure steam and combustion air to coil 14 to preheat the combustion air and withdraw heat from the low pressure steam (using heat withdrawn from at least a portion of the steam) (column 4, lines 1-3), passing the cooled low pressure steam to the condensate receiver 27 (column 4, lines 13-15), and then passing the water to the feedwater heating coil 7 as described above. Thus, the combustion air preheating in coil 14 is done using heat withdrawn from the steam upstream of the feed water preheating in coil 7, as claimed.
Wells does not teach that the water is in the liquid form when preheating the combustion air, and instead teaches that it is present as low pressure steam (steam coil 14 column 3, lines 39-42). However, low pressure steam is just a different phase of water. Instant claim 1 does not require a specific temperature and/or pressure of the water, and the instant specification does not provide any evidence that preheating with water in liquid water form as claimed, instead of in low pressure steam form as taught by Wells, provides any critical or unexpected results over the entire scope of the claim. Thus, it would have been obvious to one of ordinary skill in the art at the time of the invention to use the steam of Wells as the water of the instant claims, because steam is just liquid water used at different temperature and/or pressure, and would be expected to provide the same result of preheating the combustion air stream as claimed, absent any evidence to the contrary.
With regard to claim 2, Wells teaches that convection coil 7 produces high pressure saturated stream (column 3, lines 50-55).
With regard to claim 3, Wells teaches producing saturated high-pressure steam (feed water evaporation to obtain high pressure steam) by heating boiler feed water from steam drum 19 in heat exchanger 18 which cools the cracked product gas (column 3, lines 16-20 and 54).
With regard to claim 4, Wells teaches that the high pressure steam from the steam drum 19 is further superheated in convection coil 10 to obtain superheated high pressure steam (column 3, lines 55-56).
With regard to claims 5, 15, and 16, Wells teaches that superheated high pressure steam can supplementally be used in the combustion air preheating step (column 2, lines 45-47).
With regard to claim 7, Wells teaches that the convection coil 7 for preheating the feed water is heating by combustion gas which passes from the radiant zone to the convection zone (column 3, lines 43-46). The combustion gas after exiting the radiant zone is equivalent to flue gas as claimed (see instant specification paragraph [0008]). Wells further teaches the coil 7 is heated to a temperature, and then that the steam is superheated to 510°C, thus implicitly teaching that the first temperature is lower than the superheating temperature (column 3, lines 50-56). Wells also teaches steam superheating in coil 8 and mixing the superheated steam with the hydrocarbon feed 23 to produce a mixed feed which is cracked (column 3, lines 31-35).
With regard to claim 8, Wells teaches that the low pressure steam sent to coil 14 to preheat the combustion air (used as feed water for preheating combustion air as discussed above for claim 1) (column 3, line 65-column 4, line 3) is at a temperature of 120-325°C (column 2, line 37). This overlaps the range of 80-140°C, rendering the range prima facie obvious.
Wells is silent regarding the temperature after preheating (cooled temperature). However, Wells teaches discharging condensate which is sent to a flash pot to produce flash steam sent to a coil, and a lower pressure condensate which is sent to the condensate receiver (column 4, lines 13-20). Thus, one of ordinary skill in the art would reasonably expect that the condensate stream is liquid water at atmospheric pressure, and thus has a temperature of less than 100°C. This overlaps the range of 40-100°C of instant claim 8, rendering the range prima facie obvious.
With regard to claim 9, Wells further teaches providing high pressure steam at a pressure of 105 kg/cm3 (102 bar) to the combustion air preheating in coil 17 (column 4, line 11), which is within the range of 60 to 175 bar absolute pressure of instant claim 9. Wells further teaches forming the high pressure stream from feed water in a steam drum which is part of a steam system at 105 kg/cm3 (102 bar), thus the feed water is preheated at the same pressure level, as claimed. Therefore, while Wells does not teach the water in liquid water form at this pressure, it would have been obvious to one of ordinary skill in the art at the time of the invention to use the high pressure steam as the feed water of the instant claims, because steam is just liquid water used at different temperature and/or pressure, and would be expected to provide the same result of preheating the combustion air stream as claimed, absent any evidence to the contrary.
With regard to claims 10 and 17, Wells further teaches providing upper medium pressure steam to coil 16 to preheat the combustion air (column 4, lines 1-3), where upper medium pressure steam is at a pressure of 42 kg/cm3 (41.2 bar), which is within the range of 20-60 bar absolute pressure of instant claims 10 and 17. Wells further teaches heating the feed water in a steam system at 105 kg/cm3 (102 bar) to produce high pressure steam, which is passed to a turbine to generate the upper medium pressure steam (column 3, lines 50-60). Thus, the upper medium pressure steam is heated at the pressure of 105 kg/cm3 (102 bar), which is within the range of 60 to 175 bar absolute pressure of instant claims 10 and 17. Therefore, while Wells does not teach the water in liquid water form at this pressure, it would have been obvious to one of ordinary skill in the art at the time of the invention to use the medium pressure steam as the feed water of the instant claims, because steam is just liquid water used at different temperature and/or pressure, and would be expected to provide the same result of preheating the combustion air stream as claimed, absent any evidence to the contrary.
With regard to claim 12, Wells teaches further preheating the combustion air by contacting with saturated steam in coil 17 (column 4, lines 9-12).
With regard to claim 13, Wells teaches preheating the hydrocarbon feed 23 (input stream) by combining it with the superheated steam stream produced in coil 8 (column 3, lines 30-36) where the steam is saturated steam (column 3, lines 55-57 and 61-64).
With regard to claim 14, Wells teaches a steam cracking apparatus comprising the following components (see Figure and corresponding description columns 3-4):
A pyrolysis furnace 1 having a radiant section 2 where a hydrocarbon stream 23 is guided through the radiant section 2 to produce a product stream (column 3, lines 4-6, 18, and 31).
Fuel burners 5 for combustion of combustion air with fuel (firing heating gas with combustion air) (column 3, lines 42-44).
Combustion air preheater 13 for preheating combustion gas (column 3, lines 39-41).
Coils 7 and 10 for forming steam from feedwater (steam generators designed to generate steam) (column 3, lines 50-56).
Wells further teaches the system is designed to subject the feed water from condensate receiver 25 to preheating in a convection zone having a coil 7 (column 3, lines 50-52) and that the combustion air preheater 13 comprises coils 14 to 17 which transmit heat to combustion air from steam which is formed in the coils, and passing the cooled steam to the condensate receiver 25 (column 4, lines 13-15). Thus, the combustion air preheating is upstream of the feed water preheating, as claimed.
With regard to claim 18, Wells teaches providing upper medium pressure steam to coil 16 to preheat the combustion air (column 4, lines 1-3), where upper medium pressure steam is at a pressure of 42 kg/cm3 (41.2 bar), which is within the range of 20-60 bar absolute pressure of instant claim 18. Wells further teaches heating the feed water in a steam system at 105 kg/cm3 (102 bar) to produce high pressure steam, which is passed to a turbine to generate the upper medium pressure steam (column 3, lines 50-60). Thus, the upper medium pressure steam is heated at the pressure of 105 kg/cm3 (102 bar), which is within the range of 60 to 175 bar absolute pressure of instant claim 18.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Wells et al. (US 4,617,109) as applied to claim 1 above, and further in view of Stephens et al. (US 2003/0175642).
With regard to claim 6, Wells teaches the method above.
Wells does not explicitly teach preheating the fuel (heating gas) using heat from at least a portion of the feed water upstream of the feed water preheating.
Stephens teaches a process for combusting fuel in burners in steam cracking furnaces (Abstract). Stephens teaches an arrangement where the fuel supply (heating gas) is preheated with a heating fluid in a heat exchanger before being sent to the burners (Fig. 9B, paragraph [0090]). Stephens further teaches that preheating the fuel gas (heating gas) prior to feeding it to the burner can yield optimal results (paragraph [0087]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to add the step of preheating the fuel gas of Wells with a heating fluid as taught by Stephens, because each of Wells and Stephens teaches steam cracking where fuel gas is sent to a burner for heating the furnace, and Stephens teaches that preheating the fuel gas (heating gas) prior to feeding it to the burner can yield optimal results (paragraph [0087]).
Stephens does not specifically teach the heating fluid is water before preheating. However, Wells teaches that a portion of the steam produced in the process can be used for other process heating services not shown (column 3, lines 61-68). Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to use the steam (feed water) of Wells as the heating fluid to preheat the fuel gas, because Stephens teaches using a heating fluid but is silent regarding what the fluid is, and Wells teaches the presence of steam which can be used for other heating processes and thus would be economical to use as the heating fluid for the fuel gas.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Wells et al. (US 4,617,109) as applied to claim 1 above, and further in view of Sinatra et al. (Polimeri Europa Olefin Plant).
With regard to claim 11, Wells teaches the process above.
Wells does not teach the presence of multiple cracker furnaces with a central water system to supply the feed water.
Sinatra teaches that the presence of multiple cracking furnaces in a plant is well known and common (page 1, Process overview). Sinatra does not explicitly teach a central water source for the multiple furnaces. However, one of ordinary skill in the art would find it obvious to supply the multiple furnaces in the plant by means of a central water supply, for economic and space saving purposes. Further, it would have been obvious to one of ordinary skill in the art at the time of the invention to preheat the combustion air for each furnace separately or all in one preheater, because these are the only two options for preheating, either separately or together, and it is obvious to select either known option and also to have a reasonable expectation of success.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALYSSA L CEPLUCH whose telephone number is (571)270-5752. The examiner can normally be reached M-F, 8:30 am-5 pm, EST.
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/Alyssa L Cepluch/Examiner, Art Unit 1772
/IN SUK C BULLOCK/Supervisory Patent Examiner, Art Unit 1772