DETAILED ACTION
Examiner’s Note
This is a second non-final that is responsive to the remarks filed 04/07/2026.
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 .
Election/Restrictions
Applicant’s election without traverse of Group I, claims 1-11, in the reply filed on 10/20/2025 is acknowledged. Claims 12-16 are withdrawn.
Response to Arguments
Applicant’s arguments, see Pg. 7, filed 04/07/2026, with respect to the rejection of claim 4 under 35 USC 112(b) have been fully considered and are persuasive. Examiner notes the heat of syngas can be separate from the dew point of syngas, where the dew point of syngas is a variable value based on the temperature and pressure of the syngas. Therefore, the rejection has been withdrawn. However, upon further consideration, a new grounds of rejection is made over Abbott (US20110137089A1; cited in IDS dated 11/21/2024) in view of Guazzotti et al. (US20190039038A1), with evidentiary support provided by Ding et al. (HET Renew Power Gener. 2023, 17, 3724-3740).
Applicant’s arguments, see Pg. 7-8, filed 04/07/2026, with respect to the rejection of claim 1 under 35 USC 103 have been fully considered and are persuasive. In particular, arguments regarding Abbott not describing heat transfer occurring from the hot syngas within the first heat exchanger is acknowledged. Therefore, the rejection has been withdrawn. However, upon further consideration, a new grounds of rejection is made in view of Abbott (US20110137089A1; cited in IDS dated 11/21/2024) in view of Guazzotti et al. (US20190039038A1).
Applicant's remaining arguments filed 04/07/2026 have been fully considered but they are not persuasive.
Applicant argues on Pg. 7-8 Abbot does not teach reversing the direction of heat flow in heat exchanged 20, nor any downstream heat exchanger, in order to transfer heat from preheating fluid to the partially shifted syngas stream.
However, Abbott teaches that heat from the partial conversion gas is used to heat media within the heat exchanger, including gas, steam or water. Abbott teaches the steam and water from the heat exchangers is used to provided superheated stream used in the process, which is equivalent to “preheating fluid” as noted in the office action dated 01/08/2026 on Pg. 6. Accordingly, transferring heat exchanger heat to a fluid medium used for heating gases in the process is taught by Abbott and renders obvious the third paragraph of the second mode in instant claim 1.
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 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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C.
103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or
nonobviousness.
Claims 1, 3, and 5-11 are rejected under 35 U.S.C. 103 as being unpatentable over Abbott (US20110137089A1; cited in IDS dated 11/21/2024) in view of Guazzotti et al. (US20190039038A1).
Regarding claim 1, Abbott teaches a process for heating and converting a synthesis gas stream into a shifted gas stream (Abstract; [0007]-[0008]).
Abbott describes a process where raw synthesis gas (10) is fed to a sour shift reactor (42) comprising a header arrangement (40) that serves to transfer heat to the catalyst bed (Abstract; Fig. 2; [0045]). Abbott teaches a heated raw synthesis gas stream (50) is obtained that is mixed with steam (12) and that the resulting mixture is fed to the catalyst (46) which provides a hot-shifted synthesis gas stream (52) that is cooled with heat exchanger (20) for use in generating superheated steam (Fig. 2; [0045]). Abbott teaches the hot-shifted synthesis gas stream is optionally further passed through two heat exchangers (24 and 26) or sent to by-pass stream (30) to allow for some of the raw synthesis gas to bypass the shift reactor (Fig. 2;
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[AltContent: textbox (Figure 1. Reproduced Fig. 2 from Abbott showing the reactor parts.)][0045]).
Abbott further teaches the raw material synthesis gas stream can be heated prior to entering the reactor and that the raw material synthesis gas stream can be mixed with by-pass streams containing shifted streams, raw material gas streams, and catalyst by-pass streams, to form a combined stream that can then be subjected to one or more water-gas shift stages to further increase the hydrogen content in the syngas ([0019]-[0021]; Claims 5, 8-10, 13-14).
From the above, Abbot describes 1) mixing a raw material gas stream, which contains shifted gas, with a heat exchanger that provides a stream comprising shifted syngas and warmed syngas, 2) providing the hot syngas to a shift reactor containing a catalyst to produce a shifted syngas stream that is hot, and 3) passing the hot shifted syngas over a heat exchanger to generate superheated steam and a syngas stream that has been cooled. This process meets the limitation of “the first mode of operation” as claimed.
Abbott further teaches that the shift reactor achieves a conversion of about 0-50% of the hot raw synthesis gas, while teaching an example where about 43.6% of the carbon monoxide component is converted ([0020]; [0051]). Abbott achieving partial conversion of a syngas stream is equivalent to obtaining a “partially shifted syngas stream.” The term “partially shifted” is not given a special definition in the instant specification and the accepted meaning for the term within the art was applied to the interpretation of the claim, where partial conversion means obtaining less than 100% conversion of reactants to products.
Further, Abbott teaches the shift streams obtained from partial conversion (i.e. not 100% of conversion) are used in the process as described above, which includes transferring heat between the partially shifted gas stream and the syngas stream with heat exchangers (40, 20, 24, 26), feeding the warmed syngas to the reactor, and subsequently transferring heat from the partially shifted syngas stream with a heat exchanger (20) (Fig. 2; [0010]-[0016]; [0045]). Abbott teaches the heat exchanger media may be gas, steam, or water, and that the heat exchanger media functions by removing heat from the gas streams in the process ([0015]) . Accordingly, steam and water are considered to meet the limitation of “a preheating fluid”, as the instant specification describes superheated steam and cooled steam as comprising the preheating fluid (see at least [0043] in the instant specification).
The claim further requires “transferring heat from a hot partially shifted syngas stream to the syngas stream in the first heat exchanger to produce a warm partially shifted syngas stream and the heated syngas stream,” where Abbott does not explicitly state the hot partial shifted syngas stream is transferred through the first heat exchanger.
Guazzotti teaches an endothermic reactor for syngas production that comprises a flexible heat recovery system that contains internal and coaxial heat recovery tubes within the catalytic device (Abstract). Guazzotti teaches heat recovery from the produced hot syngas can be performed with a heat recovery system within the catalytic vessel ([0028]; Claim 18). This is equivalent to using the “first heat exchanger” as the heat recovery tubes are all contained within the same catalytic device in Guazzotti. Guazzotti teaches the reactors provide fuel efficiency of the fuel to be greater than 70% ([0029]), which is equivalent to providing a partial syngas product stream (i.e. less than 100% of fuel is converted to syngas) that is used for heat transfer to the heat recovery tubes.
Advantageously, recovering heat from the hot syngas streams and using it to heat the fuel allows the endothermic reactions to be sustained with a significant portion of the heat duty being provided by the produced gas (i.e. hot syngas) ([0002]; [0028]; [0030]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to transfer the heat from the hot syngas within the heat recovery tubes of the reactor in the process of Abbott in order to use heat from the hot syngas to sustain endothermic reactions and provided a significant portion of the heat duty, as taught by Guazzotti.
Regarding claim 3, Abbott in view of Guazzotti teach the process of claim 1 and Abbott teaches the ratio of steam (i.e. water) to feed syngas in the syngas feed stream ranges from 0.245-0.402 (Table 1) and that the syngas feed can be dry ([0034]). 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). In the instant case, the range taught by Abbott (steam to syngas feed 0.245-0.402) overlaps with the claimed range (water to dry gas ratio of between 0.2 and 0.6). Therefore, the range in Abbott renders obvious the claimed range.
Regarding claim 5, Abbott in view of Guazzotti teach the process of claim 1. Abbott teaches the sour shift reactor where the heated syngas is reacted can be adiabatic ([0024]).
Regarding claim 6, Abbott in view of Guazzotti teach the process of claim 1. Abbott teaches the temperature of shifted gas leaving the sour shift reactor ranges from 412-487 °C (Table 1; [0054]). 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). In the instant case, the range taught by Abbott (shifted gas stream ranges from 412-487 °C) overlaps with the claimed range (temperature of the shifted gas is greater than 350 °C). Therefore, the range in Abbott renders obvious the claimed range.
Regarding claim 7, Abbott in view of Guazzotti teach the process of claim 1. Abbott teaches the process includes a bypass stream (dotted line 30) that can be comprised of raw synthesis gas, heated raw synthesis gas, and steam where the bypass stream bypasses the second heat exchanger (20) in the process (Fig. 2; [0020]; [0022];[0035]; [0045]). Abbott describes the heat exchange fluids include steam ([0015]), meeting the limitation of including preheating fluid in the bypass stream.
Abbot further teaches the temperature of the hot partially shifted syngas stream (i.e. the stream leaving the shift reactor) is measured (Table 1; [0045]). Abbot further teaches the flow of the synthesis gas through the reactor, and tubes of the system should be controlled to maintain the temperature of the catalyst ([0018]; [0045]).
Regarding claim 8, Abbott in view of Guazzotti teach the process of claim 1. Abbott teaches the heat exchangers (i.e. including the second heat exchanger) can be passed super-heated steam generated from the hot shifted gas to provide a cooled stream and a raw synthesis gas that can be fed back to the reactor and preheated ([0044]; [0019]-[0020]; [0015]). Abbott teaches the raw synthesis gas used in the process contains sulfur compounds and teaches an example where the composition of the gas in mol% is H2=31.19%, CO=35.84%, CO2=14.42%, N2=0.88%, CH4 =0.38%, H2O=16.49%, and H2S+COS=0.79% ([0044]; [0049]). The instant invention describes “a circulation gas” as comprising inert gas, reducing gas, and a sulfur agent (see claim 11), where inert gas can include nitrogen, reducing gas includes hydrogen and/or carbon monoxide, and a sulfur agent that includes hydrogen sulfide (see [0039] in the instant specification). Therefore, the gas stream of Abbott comprising N2, H2, CO, and H2S+COS meets the limitation.
Regarding claim 9, Abbott in view of Guazzotti teach the processes of claim 1 and 8.
Abbott further teaches the process includes a bypass stream (dotted line 30) that can be comprised of raw synthesis gas, heated raw synthesis gas, and steam where the bypass stream bypasses the second heat exchanger (20) in the process (Fig. 2; [0020]; [0022];[0035]; [0045]). Abbott describes the heat exchange fluids include steam ([0015]), meeting the limitation of including preheating fluid in the bypass stream.
Abbot further teaches the temperature of the hot partially shifted syngas stream (i.e. the stream leaving the shift reactor) is measured (Table 1; [0045]). Abbot further teaches the flow of the synthesis gas through the reactor, and tubes of the system should be controlled to maintain the temperature of the catalyst ([0018]; [0045]).
Regarding claim 10, Abbott in view of Guazzotti teach the processes of claim 1 and 8.
Abbott further teaches the raw synthesis gas used in the process contains sulfur compounds and teaches an example where the composition of the gas in mol% is H2=31.19%, CO=35.84%, CO2=14.42%, N2=0.88%, CH4 =0.38%, H2O=16.49%, and H2S+COS=0.79% ([0044]; [0049]). The instant invention describes “a circulation gas” as comprising inert gas, reducing gas, and a sulfur agent, where inert gas can be nitrogen (see claim 11 and [0038] in instant specification). Therefore, the gas stream of Abbott comprising N2 meets the limitation.
Regarding claim 11, Abbott in view of Guazzotti teach the processes of claim 1 and 8.
Abbott teaches the raw synthesis gas used in the process contains sulfur compounds and teaches an example where the composition of the gas in mol% is H2=31.19%, CO=35.84%, CO2=14.42%, N2=0.88%, CH4 =0.38%, H2O=16.49%, and H2S+COS=0.79% ([0044]; [0049]). The instant invention describes “a reducing gas” as including hydrogen and/or carbon monoxide while hydrogen sulfide (see [0039] in instant specification) and carbonyl sulfide (COS) taught by Abbott includes sulfur and meets the limitation of a sulfur agent.
Claim 2 is rejected under 35 U.S.C. 103 as being unpatentable over Abbott (US20110137089A1; cited in IDS dated 11/21/2024) in view of Guazzotti et al. (US20190039038A1) and further in view of Lee et al. (US20110027170A1).
Regarding claim 2, Abbott in view of Guazzotti teach the processes of claim 1 and the claim further requires “the temperature of the preheating fluid is between 250 and 500 °C” to which Abbott does not explicitly state the temperature of the preheating fluid.
Lee teaches a process of operating a water-gas shift reactor with syngas feeds where the syngas is preheated with a heat exchanger that has a temperature of 170-270 °C (Abstract; [0013]-[0016]; [0046]; [0050]). A heat exchanger operates with a fluid medium (i.e. water, steam, etc.) and necessarily includes a preheating fluid, rendering obvious the preheating fluid. 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). In the instant case, the range taught by Lee (preheater at 170-270 °C) overlaps with the claimed range (preheating fluid is between 250 and 500 °C). Therefore, the range in Lee renders obvious the claimed range.
Advantageously, maintaining a preheater at these temperatures ensures the reforming reactor isn’t overheated and serves to increase the conversion of carbon monoxide ([0049]).
Thus, prior to the effective filing date of the claimed invention, it would have been obvious to one of ordinary skill in the art to operate a preheater at 170-270 °C in the method of Abbott in order to ensure the reactor doesn’t overheat and to increase the conversion of carbon monoxide in the syngas, as taught by Lee.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Abbott (US20110137089A1; cited in IDS dated 11/21/2024) in view of Guazzotti et al. (US20190039038A1), with evidentiary support provided by Ding et al. (HET Renew Power Gener. 2023, 17, 3724-3740).
Regarding claim 4, Abbott in view of Guazzotti teach the process of claim 1 and Abbott teaches a heated syngas stream is obtained ([0020]-[0021]). Abbott teaches the heated raw synthesis gas is passed at an elevated temperature and pressure to the catalyst, where the temperature is between 250 and 500 °C and the pressure is up to about 75 bar ([0021]). Abbott teaches the shifted syngas stream is cooled to below the dew point in order to condense water (Claim 15).
While Abbott does not explicitly teach the temperature of the heated raw syngas stream is greater than the dew point, Abbott does not state condensation occurs within the heated raw syngas stream and further teaches a skilled artisan that the shifted syngas needs to be cooled below the dew point in order to condense water from the syngas stream. Accordingly, a skilled artisan would recognize the temperature and pressure that Abbott heats the syngas stream to would not result in condensation and is above the dew point of syngas, as evidenced by Ding who teaches the dew point temperature of syngas increases with increasing pressure (Fig. 9; Fig. 11; Pg. 3733-3734, 4.3.3), where at pressures of 75 bar, as taught by Abbott, syngas would be above the dew point temperature. From the physical property table provided by Ding, a skilled artisan could readily determine the proper temperature and pressure to apply to the syngas in order to keep it over the dew point in order to avoid condensation. 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. In the instant case, there is no evidence of record showing the claimed range of “the temperature of the heated syngas stream is between 15 °C and 30 °C higher than the dew point of the heated syngas stream” to be critical, so long as the heated syngas is hot enough to avoid condensation (as stated in [0032] of the specification). See MPEP 2144.05.II.A.
Conclusion
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/JORDAN W TAYLOR/Examiner, Art Unit 1738
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