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 .
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 03/07/2023 has been considered by the examiner.
Election/Restrictions
Claim 12 withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 10/13/2025.
Applicant’s election without traverse of claims 1-11 and 13 in the reply filed on 10/13/2025 is acknowledged.
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.
Claim 13 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.
Claim 13 recites the limitation "one or more inert gases" in line 1. There is insufficient antecedent basis for this limitation in the claim. For purposes of examination, this claim limitation is interpreted as one or more inert gases present in the off gas in light of the instant specification [0028].
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.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 1, 3-7 are rejected under 35 U.S.C. 103 as being unpatentable over Vente et al (EP 3604210 A1, cited in IDS 03/07/2023) in view of Sundaram et al (US 10350538 B2, cited in IDS 03/07/2023) and Najmi et al (“A systematic approach to the modeling and simulation of a Sorption Enhanced Water Gas Shift (SEWGS) process for CO2 capture”).
Regarding claim 1, Vente discloses in step (a), a mixture of the incoming gas and steam is subjected to a separation-enhanced water gas shift reaction ([0017] meeting limitation “a sorption-enhanced water-gas shift (SEWGS) process”). The incoming gas is contacted with a catalyst capable of catalysing the water gas shift reaction ([0017] meeting limitation “a SEWGS reactor containing a catalyst”). The water gas shift reaction is the forward reaction in the following equilibrium:
(5) CO + H2O ↔ H2 + CO2
BOF and BF gas contains about 50 wt% (for BF gas) or even 80 wt% (for BOF gas) carbon oxide species (CO + CO2) and is very low in H2, and the inventors surprisingly found that such a gas could be successfully shifted in a water gas shift reaction ([0017] meeting limitation “a reaction step, wherein a feed gas comprising COx, wherein x = 1 - 2, and H2O is fed into a SEWGS reactor”). Due to the abundance of CO in BOF gas and the addition of steam, the forward reaction is favoured and H2 and CO2 are formed in step (a) ([0017] meeting limitation “the formation of a CO2 product stream and an H2 product stream”). Furthermore, in the separation-enhanced water has shift reaction, CO2 is separated from the remaining components and removed from the gas phase equilibrium, e.g. by adsorption on the catalyst ([0017] meeting limitation “a catalyst and sorbent material capable of adsorbing CO2, thereby forming the H2 product stream and a sorbent material loaded with CO2”). Preferably, said catalyst is a sorbent capable of adsorbing CO2 ([0020]). Preferably, such a steam rinse and/or purge is implemented, as this was found to enhance product recovery ([0019]). Regeneration of the loaded sorbent is known in the art and typically involves (i) a rinse step wherein the sorbent is flushed with a rinse gas comprising steam ([0021] meeting limitation “(b) a rinse step, wherein steam is fed to the SEWGS reactor”), (ii) one or more pressure equalization steps ([0021] meeting limitation “(c) a pre-blowdown step, wherein the pressure in the SEWGS reactor is reduced”), (iii) a depressurization step ([0021] meeting limitation “(d) a blowdown step, wherein the pressure in the SEWGS reactor is reduced”), (iv) a purge step wherein the sorbent is flushed with a purge gas comprising steam ([0021] meeting limitation “(e) a purge step, wherein steam is fed to the SEWGS reactor”). The skilled person is acquainted with the separation-enhanced water gas shift reaction and knows what conditions should be applied in order to obtain a first product gas comprising H2 and N2 and adsorbed CO2 ([0022]). For example… the pressure is most preferably 5 – 50 bar ([0022] meeting limitation “establishing a pressure in the range of 5 - 50 bar”). In step (iii), the pressure in the reactor is reduced to ambient, during which some CO2 is already desorbed from the column ([0021] meeting limitation “the pressure in the SEWGS reactor is reduced to the regeneration pressure in the range of 1 - 5 bar, thereby releasing at least part of the CO2 from the loaded sorbent material, thereby forming the CO2 product stream” since ambient pressure is about 1 bar). During step (iv), the sorbent is flushed with steam, during which H2O molecules replace the adsorbed CO2 molecules ([0021] meeting limitation “thereby releasing further CO2 molecules from the SEWGS reactor”).
Regarding the limitation “to establish a blowdown pressure in the range of 0.5 - 1.5 times the partial pressure of CO and CO2 in the feed gas of step (a)”, Vente discloses on page 11 Table 1 Composition of starting material (in kmol). BOF, i.e. feed gas, is composed of 100 kmol N2, 18 kmol H2, 300 kmol CO, 110 kmol CO2. The mol fraction of CO and CO2 combined is 0.78. Since Vente discloses the pressure is most preferably 5 – 50 bar ([0022]), the partial pressure of CO and CO2 in the feed gas would be in the range of 3.88 – 385.83 bar.
Vente does not disclose “a blowdown pressure in the range of 0.5 - 1.5 times the partial pressure of CO and CO2 in the feed gas of step (a)”.
Sundaram discloses syngas can be effectively separated to generate high purity carbon dioxide and hydrogen streams, while reducing and/or minimizing the energy required for the separation, and without needing to reduce the temperature of the flue gas (abstract). In Example 1 Sundaram discloses the first step in the cycle is a feed step at high pressure, such as 28 bara, for 60-150 seconds during which feed gas is supplied to a feed end of a PSA reactor vessel (Col. 18 lines 24-27). As the feed gas is supplied to a feed end of the vessel, a hydrogen product is produced from a product side (Col. 18 lines 33-34). After a sufficient amount of CO2 is adsorbed, such as about 85% of the capacity of the adsorbent, an equalizationdown step is performed to lower the pressure of the spent bed and repressurize a different bed in the cycle (Col. 18 lines 37-41). At the end of the equalizationdown step, the reactor vessel is at a pressure of about 14 bara (Col. 18 lines 42-44). 14 bar is within the partial pressure of CO and CO2 in the feed gas disclosed by Vente.
Sundaram further teaches the use of multiple blow down steps can be desirable for creating blow down streams that are easier to subsequently process (Col. 8 lines 36-38). In many embodiments, maintaining a pressure above atmospheric pressure in the reactor can assist with the adsorbent retaining CO2 until a subsequent purge step when desorption is desired (Col. 8 lines 25-28).
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 have the pre-blowdown step, wherein the pressure in the SEWGS reactor is reduced to establish a blowdown pressure in the range of 0.5 - 1.5 times the partial pressure of CO and CO2 in the feed gas of step (a) in the method of Vente in order for the adsorbent to retain CO2 and to create blow down streams that are easier to subsequently process as taught by Sundaram.
Vente does not disclose “wherein the off gas released from the reactor during step (c) is collected separately from the C02 product stream released from the reactor during step (d)”.
Najmi discloses dynamic operation of a multi-train Sorption Enhanced Water Gas Shift (SEWGS) system (abstract). Syngas is converted to a H2-rich product and a separate CO2-rich stream is also produced (abstract). As shown in Fig. 1, the SEWGS cycle consists of eleven distinct steps, which each reactor undergoes in sequence (Pg. 83 right column par. 3). Pressure swing cycle starts with three pressure reduction steps called pressure equalization (Eq1- Eq3), i.e. pre-blowdown steps (Pg. 83 right column par. 3). During each pressure equalization step, reactor is connected to another reactor being pressurized (Req3- Req1) (Pg. 83 right column par. 3). CO2 is recovered during counter-current depressurization, i.e. a blowdown step (Pg. 83 right column par. 3). A re-pressurization step is carried out counter-currently by sending part of the H2-rich product from another reactor being in the feed step (Pg. 83 right column par. 4). The reactor pressure is hence increased back to the feed pressure (27 bar) to start a new cycle (Pg. 83 right column par. 4). Fig. 1 illustrates the streams from the equalization steps are fed into reactors in order to repressurize the H2 -rich stream while the CO2-rich stream resulting from the depressurization step is collected as a product.
Thus, prior to the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art for the off gas released from the reactor during step (c) to be collected separately from the C02 product stream released from the reactor during step (d) in the method of Vente in order to repressurize the reactor back to the feed pressure to start a new cycle as taught by Najmi.
Regarding claim 3, Vente in view of Sundaram and Najmi discloses all the limitations in the claims as set forth above including at the end of the equalizationdown step, the reactor vessel is at a pressure of about 14 bara (Sundaram Col. 18 lines 42-44) and for example… the pressure is most preferably 5 – 50 bar (Vente [0022]). Since Vente discloses a feed pressure of 5-50 bar, the equalization pressure or pre-blowdown step pressure would be a reduction of pressure in the range of 1-25 bar in the cases where the feed pressure is 15-39 bar.
Regarding claim 4, Vente in view of Sundaram and Najmi discloses all the limitations in the claims as set forth above including BOF, i.e. feed gas, is composed of 100 kmol N2, 18 kmol H2, 300 kmol CO, 110 kmol CO2 (Vente Pg. 11 Table 1). This is equivalent to 57 mol % CO and 21% CO2, meeting claim limitations “wherein the feedstock contains … 0 - 80 mol%CO2” and “wherein the total content of COx in the feedstock is at least 2 mol%.”
Vente does not disclose “the feedstock contains 0-10 mol % CO”.
Sundaram discloses an example of a turbine exhaust gas composition can be about 10-15 vol% carbon dioxide, about 60-80 vol % H2, 5-30 vol % carbon monoxide and a remaining amount of water and other trace species (Col. 18 lines 29-33). Under the ideal gas assumption, vol % is equivalent to mole %. Therefore, Sundaram’s disclosure of 5-30 mol % carbon monoxide overlaps with the claimed 0-10 mol% CO.
As set forth in MPEP 2144.05, in the case where the claimed range “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists, In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). In the instant case, the range taught by Sundaram (5-30 mol %) overlaps with the claimed range (0-10 mol% ). Therefore, the range in Sundaram renders obvious the claimed range.
Thus, prior to the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art for the feedstock to contain 0-10 mol % CO in the method of Vente in order to use turbine exhaust gas as a feed gas as taught by Sundaram.
Regarding claim 5, Vente in view of Sundaram and Najmi discloses all the limitations in the claims as set forth above including Vente discloses regeneration of the loaded sorbent is known in the art and typically involves (i) a rinse step wherein the sorbent is flushed with a rinse gas comprising steam ([0021]), (ii) one or more pressure equalization steps ([0021] meeting limitation “further comprising one or more pressure equalization steps, wherein the SEWGS reactor is depressurized directly after the rinse step (b)”). Vente discloses (iv) a purge step wherein the sorbent is flushed with a purge gas comprising steam, (v) one or more pressure equalization steps, and (vi) a repressurization step ([0021]). During the pressure equalization steps (v), the reactor is pressurized again until the desired pressure for step (a1) is reached ([0021] meeting limitation “the SEWGS reactor is repressurized directly after the purge step (e)”).
Regarding claim 6, Vente in view of Sundaram and Najmi discloses all the limitations in the claims as set forth above including during the pressure equalization steps (v), the reactor is pressurized again until the desired pressure for step (a1) is reached ([0021]), where step (a1) is the first step in the next cycle.
Regarding claim 7, Vente in view of Sundaram and Najmi discloses all the limitations in the claims as set forth and Vente further discloses Preferable, the compression energy that is released in step (ii) is used in step (v), which can be accomplished by using multiple reactors in series.
Claims 2 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Vente et al (EP 3604210 A1, cited in IDS 03/07/2023) in view of Sundaram et al (US 10350538 B2, cited in IDS 03/07/2023) and Najmi et al (“A systematic approach to the modeling and simulation of a Sorption Enhanced Water Gas Shift (SEWGS) process for CO2 capture”), and in further view of Hufton et al (EP 2072111A2).
Regarding claim 2, Vente in view of Sundaram and Najmi discloses all the limitations in the claims as set forth above including Vente discloses the skilled person is acquainted with the separation-enhanced water gas shift reaction and knows what conditions should be applied in order to obtain a first product gas comprising H2 and N2 and adsorbed CO2 ([0022]). For example… the pressure is most preferably 5 – 50 bar ([0022] meeting limitation “wherein the feed pressure is in the range of 5 - 50 bar”).
Regarding claims 2 and 8, Vente in view of Sundaram and Najmi disclose all the limitations as set forth above but does not disclose “the blowdown pressure is in the range of 2 - 10 bar” or “the blowdown pressure is in the range 3 - 7 bar”.
Hufton discloses a method of separating CO2 from a syngas…uses a bed of high temperature reactive solids ([0023]). If the syngas also contains CO, it is advantageous to inject steam with the syngas and include a high temperature shift catalyst in the bed with the reactive solid ([0036]). The high temperature shift catalyst will catalyze the water gas shift reaction (CO+H2O→CO2+H2) and permit the CO to react with the steam to form CO2 and hydrogen ([0036]). The CO2 thus formed will be adsorbed and removed from the syngas, more hydrogen will be produced and the shift reaction will be pushed further to completion ([0036]). Reaction of CO2 with the reactive solid effectively removes it from the gas phase, yielding a product gas with an increased concentration of hydrogen that is conducted away from the reactive solid ([0025]). Once the majority of reactive solid in the bed is converted to the second solid compound, the capability for removing CO2 from the gas diminishes and the bed is regenerated by reducing the partial pressure of CO2 ([0025]). In the current embodiment, the reactive solid is depressurized to a lower pressure, for example, between about 5 bar and about 0.3 bar, followed by a purge of the bed using a purge gas stream, preferably steam, also at a low pressure (between about 5 bar and about 0.3 bar) ([0025]).
As set forth in MPEP 2144.05, in the case where the claimed range “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists, In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). In the instant case, the range taught by Hufton (0.3 to 5 bar) overlaps with the claim 2 range (2 to 10 bar) and the claim 8 range (3 to 7 bar). Therefore, the range in Hufton renders obvious the claimed range.
Thus, prior to the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art for the blowdown pressure to be in the range of 2 - 10 bar and 3 – 7 bar in the method of Vente in view of Sundaram and Najmi in order to regenerate the adsorbent as taught by Hufton.
Claim 9 is rejected under 35 U.S.C. 103 as being unpatentable over Vente et al (EP 3604210 A1, cited in IDS 03/07/2023) in view of Sundaram et al (US 10350538 B2, cited in IDS 03/07/2023) and Najmi et al (“A systematic approach to the modeling and simulation of a Sorption Enhanced Water Gas Shift (SEWGS) process for CO2 capture”), and in further view of Chen et al ( US 20100288123 A1).
Regarding claim 9, Vente in view of Sundaram and Najmi discloses all the limitations in the claims as set forth above but does not disclose “wherein the off-gas of the pre-blowdown step (c) is recycled to reaction step (a) or collected as tail gas”.
Chen discloses the water gas shift reaction product is then introduced into a H2 PSA unit 8 via line 7 in order to produce a high purity hydrogen ([0014]). The H2 PSA unit 8 utilized can be any H2 PSA unit known in the art and can comprise anywhere from two to twelve adsorption beds ([0014]). During the process of H2 production, each of the adsorption beds will individually under go a cycle that generally comprises: a) pressurization with pure hydrogen product, b) constant feed and hydrogen product release; c) pressure equalization to transfer high pressure hydrogen-rich void gas to another bed at low pressure, the other bed being about to commence product pressurization; d) depressurization to slightly above atmospheric pressure; e) purge using intermediate product hydrogen; and f) pressure equalization with another bed at higher pressure to accept hydrogen-rich void gas ([0014]). As a result of this process, two separate gas streams are obtained- one that is a gaseous high purity hydrogen stream… and the other which is often referred to as a H2 PSA tail gas which is withdrawn after desorption of a bed ([0014]). The H2 PSA tail gas withdrawn from the adsorption beds of the H2 PSA unit 8 during the depressurization and purge steps generally comprises carbon dioxide, methane and carbon monoxide ([0014]).
Chen further discloses rather than use the H2 PSA tail gas stream as a makeup fuel as in the prior art, the H2 PSA tail gas stream is instead treated in order to remove the valuable CO2 present ([0017]).
Thus, prior to the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art for the off-gas of the pre-blowdown step (c) to be collected as tail gas in the method of Vente in view of Sundaram and Najmi in order to remove the valuable CO2 present as taught by Chen.
Chen further discloses a portion of the H2 PSA tail gas may be separated from the H2 PSA tail gas prior to insertion into the CO2 VSA unit 11 and directed via line 10.1 to be added to line 13 which provides the first CO2 lean gas stream to be used as makeup fuel in the SHR unit 3 ([0017]), i.e. recycling the reaction to step (a).
Thus, prior to the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art for the off-gas of the pre-blowdown step (c) to be recycled to reaction step (a) in the method of Vente in view of Sundaram and Najmi in order to reuse the off-gas as makeup fuel as taught by Chen.
Claims 10-11 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Vente et al (EP 3604210 A1, cited in IDS 03/07/2023) in view of Sundaram et al (US 10350538 B2, cited in IDS 03/07/2023) and Najmi et al (“A systematic approach to the modeling and simulation of a Sorption Enhanced Water Gas Shift (SEWGS) process for CO2 capture”), Chen et al ( US 20100288123 A1) and in further view of Hufton et al (EP 2072111A2).
Regarding claim 10, Vente in view of Sundaram, Najmi and Chen discloses all the limitations in the claims as set forth above including Chen discloses wherein the off-gas of the pre- blowdown step (c) is recycled to reaction step (a) as discussed in the rejection of claim 9, but does not disclose “the blowdown pressure is in the range of 2 - 4 bar”.
Hufton discloses a method of separating CO2 from a syngas…uses a bed of high temperature reactive solids ([0023]). If the syngas also contains CO, it is advantageous to inject steam with the syngas and include a high temperature shift catalyst in the bed with the reactive solid ([0036]). The high temperature shift catalyst will catalyze the water gas shift reaction (CO+H2O→CO2+H2) and permit the CO to react with the steam to form CO2 and hydrogen ([0036]). The CO2 thus formed will be adsorbed and removed from the syngas, more hydrogen will be produced and the shift reaction will be pushed further to completion ([0036]). Reaction of CO2 with the reactive solid effectively removes it from the gas phase, yielding a product gas with an increased concentration of hydrogen that is conducted away from the reactive solid ([0025]). Once the majority of reactive solid in the bed is converted to the second solid compound, the capability for removing CO2 from the gas diminishes and the bed is regenerated by reducing the partial pressure of CO2 ([0025]). In the current embodiment, the reactive solid is depressurized to a lower pressure, for example, between about 5 bar and about 0.3 bar, followed by a purge of the bed using a purge gas stream, preferably steam, also at a low pressure (between about 5 bar and about 0.3 bar) ([0025]).
As set forth in MPEP 2144.05, in the case where the claimed range “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists, In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). In the instant case, the range taught by Hufton (0.3 to 5 bar) overlaps with the claimed range (2 to 4 bar). Therefore, the range in Hufton renders obvious the claimed range.
Thus, prior to the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art for the blowdown pressure to be in the range of 2 - 4 bar in the method of Vente in view of Sundaram, Najmi, and Chen in order to regenerate the adsorbent as taught by Hufton.
Regarding claim 11, Vente in view of Sundaram, Najmi and Chen discloses all the limitations in the claims as set forth above including Chen discloses wherein the off-gas of the pre- blowdown step (c) is collected as tail gas as discussed in the rejection of claim 9, but does not disclose “the blowdown pressure is in the range of 3 - 8 bar”.
Hufton discloses a method of separating CO2 from a syngas…uses a bed of high temperature reactive solids ([0023]). If the syngas also contains CO, it is advantageous to inject steam with the syngas and include a high temperature shift catalyst in the bed with the reactive solid ([0036]). The high temperature shift catalyst will catalyze the water gas shift reaction (CO+H2O→CO2+H2) and permit the CO to react with the steam to form CO2 and hydrogen ([0036]). The CO2 thus formed will be adsorbed and removed from the syngas, more hydrogen will be produced and the shift reaction will be pushed further to completion ([0036]). Reaction of CO2 with the reactive solid effectively removes it from the gas phase, yielding a product gas with an increased concentration of hydrogen that is conducted away from the reactive solid ([0025]). Once the majority of reactive solid in the bed is converted to the second solid compound, the capability for removing CO2 from the gas diminishes and the bed is regenerated by reducing the partial pressure of CO2 ([0025]). In the current embodiment, the reactive solid is depressurized to a lower pressure, for example, between about 5 bar and about 0.3 bar, followed by a purge of the bed using a purge gas stream, preferably steam, also at a low pressure (between about 5 bar and about 0.3 bar) ([0025]).
As set forth in MPEP 2144.05, in the case where the claimed range “overlap or lie inside ranges disclosed by the prior art”, a prima facie case of obviousness exists, In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). In the instant case, the range taught by Hufton (0.3 to 5 bar) overlaps with the claimed range (3 to 8 bar). Therefore, the range in Hufton renders obvious the claimed range.
Thus, prior to the effective filing date of the claimed invention it would have been obvious to one of ordinary skill in the art for the blowdown pressure to be in the range of 3 - 8 bar in the method of Vente in view of Sundaram, Najmi, and Chen in order to regenerate the adsorbent as taught by Hufton.
Regarding claim 13, Vente in view of Sundaram, Najmi, Chen and Hufton discloses all the limitations in the claims as set forth above including Chen discloses The H2 PSA tail gas withdrawn from the adsorption beds of the H2 PSA unit 8 during the depressurization and purge steps generally comprises carbon dioxide, methane and carbon monoxide ([0014]).
Conclusion
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/N.L.Q./Examiner, Art Unit 1738
/MICHAEL FORREST/Primary Examiner, Art Unit 1738