Priority
This application is a 371 of PCT/GB2021/052422 (09/17/2021) and claims foreign priority to UNITED KINGDOM 2016417.4 (10/16/2020).
Status
Claim 1-11, 14 are pending. Claim 14 was newly presented.
Claim rejections not reiterated in this action are withdrawn.
Claim Rejections - 35 USC § 103
Claims 1-5 are rejected under 35 U.S.C. 103 as being unpatentable over Balaji et al. (WO2020114899, published 2020-06-11) in view of Kern et al. (US20150336795).
Regarding claim 1, Balaji teaches a process for producing a gas stream comprising carbon monoxide comprising the steps of (a) feeding a gas mixture comprising carbon dioxide and hydrogen to a burner disposed in a reverse water-gas shift vessel (claim 1: “A process for converting carbon dioxide and hydrogen into a product stream comprising carbon monoxide, water and hydrogen, the process comprising introducing carbon dioxide, hydrogen and oxygen into a reaction vessel, and performing a reverse water gas shift reaction at elevated temperature”, “wherein at least the hydrogen rich gas stream and the oxygen rich gas stream are introduced into the reaction vessel via a burner”) and
combusting it with a sub-stoichiometric amount of an oxygen gas stream having a purity of at least 94% by volume (claim 1: “wherein the hydrogen and oxygen in the hydrogen rich gas stream and oxygen rich gas stream undergo a combustion reaction upon entering the reaction vessel, thereby providing the heating energy required for the reverse water-gas shift reaction;”; p. 6: “Preferably, the oxygen rich gas stream comprises of high purity oxygen … specifically 90 % and higher by volume.”)
to form a combusted gas mixture comprising carbon monoxide, carbon dioxide,hydrogen and steam (claim 1: “a product stream comprising carbon monoxide, water and hydrogen”),
(c) cooling the crude product gas mixture to below the dew point and recovering a condensate to form a dewatered product gas, (p. 11: “According to the present disclosure, the cooled product stream comprising carbon monoxide, hydrogen, steam and unconverted carbon dioxide is subjected to further cooling at least to, and beyond, the dew point to provide a gas stream comprising of carbon monoxide, hydrogen, unconverted carbon dioxide and liquid water which can then be separated from the product gas stream. Separators suitable for this purpose are known to people skilled in the art. The liquid water stream thus separated is then recycled back to the water splitter.”)
(d) removing carbon dioxide from the dewatered product gas in a carbon dioxide removal unit to form the gas stream comprising carbon monoxide, and (e) combining carbon dioxide recovered by the carbon dioxide removal unit with the gas mixture comprising hydrogen and carbon dioxide fed to the reverse water-gas shift vessel (p. 11: “unconverted carbon dioxide and liquid water which can then be separated from the product gas stream. … As long as the product stream comprising carbon monoxide and hydrogen produced by the process described above, still comprises unconverted carbon dioxide, the product stream advantageously may be repeatedly subjected to said process steps to convert all carbon dioxide present.”).
Although Balaji teaches that catalysts are required for low temperature (p. 2: “RWGS reaction at lower temperatures at around 600 - 1000 °C require catalysts to enable the conversion of carbon dioxide to carbon monoxide.”), Balaji endeavors to improve the process by increasing the temperature sufficiently to remove the need for catalyst (p. 4: “the temperature in the reaction vessel is maintained in the range of 1000 to 1500 °C by varying the molar ratio of hydrogen to oxygen, which are introduced into the reaction vessel in the hydrogen rich oxygen rich gas stream, respectively.”).
Thus, Balaji does not specifically teach claim 1’s: (b) passing the combusted gas mixture though a bed of reverse water-gas shift catalyst disposed within the reverse water-gas shift vessel to form a crude product gas mixture containing carbon monoxide, steam, hydrogen and carbon dioxide.
Kern teaches the same reverse water gas shift (RWGS) reaction of reacting CO2 with H2 at high temperature in a reactor over a catalyst be to form CO (Abstract; claim 8; [0010]; [0064]-[065]), including the introduction of oxygen for combustion with hydrogen to increase the reactor temperature ([0058]: “The regulated addition of an oxygen”, “preferably oxygen of technical grade purity (advantageously greater than 95% by volume oxygen, preferably greater than 99% oxygen, particularly preferably greater than 99.5% oxygen)”, “the desired temperature in the RWGS reactor serves as guide variable for the oxygen metering”, “For example, an atomic ratio, i.e. hydrogen to oxygen, of 10:1 to 100:1, preferably 20:1 to 80:1, particularly preferably 25:1 to 60:1, in particular 30:1 to 50:1, is used;”; [0061]-[0062]). Kern teaches that although very high temperature RWGS reactions would be effective, it poses engineering and heat costs ([0013]).
One of ordinary skill in the art following the teaching of Balaji without a catalyst due to very high temperatures would have also considered using the known reaction that utilizes catalysts at a lower temperature as specifically disclosed by Balaji. One of ordinary skill in the art would have known that operating at a very high temperature poses engineering and heat cost challenges as is well known and disclosed by Kern.
Regarding claim 2 specifying a ratio of H2:CO2, Balaji teaches Examples with the ratio of 3:1 (p. 18, Table 1). Kern teaches similar ratios, including within the claimed range (Fig.3; claim 12: “the molar ratio of carbon dioxide to hydrogen in the hydrogen-comprising gas mixture of 1:2 to 1:2.5”, i.e. H2:CO2 of 2:1 to 2.5:1).
Regarding claim 3, Balaji teaches (p. 5-6: “Preferably, the gas stream comprising carbon dioxide contains carbon dioxide in the range of 30 to 100 volume %, and even more preferred 50 to 100 volume %.”, “The hydrogen rich gas stream comprises hydrogen as a main component… 65 % and higher by volume”; p. 18, Table 1 H2:CO2 3:1).
Regarding claim 4, Balaji teaches source of CO2 as flue gases (p. 5: “Sources of the carbon dioxide may be diverse, such as for example, but not limited to carbon dioxide captured from air or from flue gases, off-gases, and the like.”).
Regarding claim 5, Balaji teaches electrolysis of water as the source of hydrogen and oxygen (p. 10 “According to the present disclosure, a water splitter can be used to produce at least a part of the hydrogen rich gas stream and the oxygen rich gas stream.”).
Regarding claim 14 specifying the ratio of CO2 in the feed, Balaji teaches wide ranges of “A gas stream comprising carbon dioxide herein means a gas stream comprising from 1% to 100% carbon dioxide by volume” and “Preferably, the gas stream comprising carbon dioxide contains carbon dioxide in the range of 30 to 100 volume %” (p. 5-6) which encompass the claimed range and further that the ratio of hydrogen to carbon dioxide requires adjustment (p. 9). One of ordinary skill in the art would have considered the composition of the feed stream in the RWGS reaction to be a results effective variable that would need adjustment/optimization according to the particular reaction conditions as taught by Balaji. In the course of such optimization one of ordinary skill in the art would have arrived at the claimed invention with a reasonable expectation of success.
Claims 6-11 are rejected under 35 U.S.C. 103 as being unpatentable over Balaji et al. (WO2020114899, published 2020-06-11) in view of Kern et al. (US20150336795) as applied to claims 1-5 above and further in view of Hinman et al. (US20090313886) in view of Doty et al. (US20130034478).
Regarding claim 6 specifying the RWGS catalyst, Balaji cites to a number of references teaching nickel catalysts for RWGS reaction (p. 3), but does not specifically teach the catalyst as claimed. Kern also teaches nickel catalysts for use in RWGS reaction ([0010]).
Hinman teaches a process and an apparatus for producing a gas stream comprising CO ([0018], [0020], [0027], [0043],[0066], [0079], [0092] and [0097]). The process comprises splitting water into H2 and O2, supplying the H2 together with CO2 to a catalytic RWGS wherein a gas stream comprising CO, H2 and CO2 is produced (Fig. 1, [0018]-[0029]). Water obtained during RWGS is separated in a condenser and H2 and CO2 are separated using a filter ([0043]). The separated CO2 is recycled to the RWGS ([0043]). The RWGS can comprise a burner which combusts H2 and O2 to heat the RWGS reaction ([0092]). Hinman teaches nickel catalysts, Ni/Al2O3, can be used as RWGS catalyst (claim 14; [0068]-[0073]). Hinman discloses adding H2 to CO2 to the RWGS in a ratio of 3 to 1.
Doty discloses (Fig. 3) a process and corresponding apparatus for producing a gas stream comprising CO. The process comprises splitting water into H2 and O2, supplying the H2 together with CO2 to a RWGS (10) wherein a gas stream comprising CO, H2 and CO2 is produced. Water obtained during RWGS is separated in a condenser (22) and thereafter CO2 is separated (24) and returned to the RWGS.
One of ordinary skill in the art following the teaching of the cited art would have considered using catalysts known to be successful and interchanging them to optimize performance in an apparatus for RWGS reaction and arrive at the claimed invention with a reasonable expectation of success.
Regarding claim 7, Doty teaches washing the condensed CO2 ([0197]).
Regarding claim 8, Doty teaches recycling the condensed water to the electrolyzer ([0155]).
Regarding claims 9-11, Doty teaches processing the RWGS product and feeding to FT synthesis unit (Abstract; Fig. 3; [0099], [0126], [0138], [0167]-[0172], [0193]) which one of ordinary skill in the art would consider in combination with Balaji, Kern, and Hinman and arrive at the claimed invention with a reasonable expectation of success.
With each of the above claims, the level of skill in the art is very high such that one of ordinary skill in the art would consider routine the combination of elements from the teaching of the art. One of ordinary skill in the art would have recognized that the results of the combination would be predictable due to the well-known processes and optimizations routinely performed in the art. Thus, one of ordinary skill in the art would have arrived at the invention as claimed with a reasonable expectation of success before the effective filing date of the claimed invention.
With each of the above claims, the level of skill in the art is very high such that one of ordinary skill in the art would consider routine the combination of elements from the teaching of the art. One of ordinary skill in the art would have recognized that the results of the combination would be predictable due to the well-known processes and optimizations routinely performed in the art. Thus, one of ordinary skill in the art would have arrived at the invention as claimed with a reasonable expectation of success before the effective filing date of the claimed invention.
Response to Remarks - 35 USC § 103
Applicant argues Balaji requires that "no catalyst is present in the reaction vessel." Balaji at Abstract and 4. Thus, one skilled in the art would not modify Balaji by including a bed of catalyst in the reverse water-gas shift reactor, as a key feature of Balaji is to exclude a catalyst.
This argument is not persuasive because Balaji teaches what is well-known in the art that catalysts are used at lower temperatures (p. 2-3: “RWGS reaction at lower temperatures at around 600 - 1000 °C require catalysts to enable the conversion of carbon dioxide to carbon monoxide.”) and Balaji’s teaching is to use higher temperatures to achieve conversion to without the need for a catalyst which can suffer from poisons (p. 2-3). However, one of ordinary skill in the art would have understood that Balaji’s process would also function with a catalyst at lower temperatures. Thus, Balaji does not teach away from the use of a catalyst because of the disclosure of success with not using a catalyst because it does not criticize, discredit, or otherwise discourage the solution claimed. MPEP 2145.
Applicant argues “the office does not identify disclosure in Balaji that teaches or suggests steps (d) and (e) of Applicant's claim 1.
The argument is not persuasive because giving the claim steps (d) and (e) their BRI in view of the claim process comprising does not distinguish the prior art from the claims. Claim 1’s step (d) requires removing CO2 from the dewatered product gas to form the gas stream comprising CO which corresponds to Balaji’s teaching of the “cooled product gas stream comprising … carbon dioxide, thus obtained from the first reaction vessel”. Claim 1’s step (e) requires combining said CO2 with the gas mixture comprising hydrogen and CO2 to the RWGS vessel which corresponds to Balaji’s teaching of feeding the separated product gas fed to a second RWGS. Thus, CO2 is removed and combined comprising the same manner as in the instant claims.
Applicant argues Hinman and Doty add nothing to Balaji and/or Kern to motivate one skilled in the art to include a catalyst in Balaji's processes when Balaji teaches the exclusion of catalysts.
This argument is not persuasive because one of ordinary skill in the art would have had a reasonable expectation of success in using a catalyst in a RWGS reaction as taught by Balaji and Kern, including as further suggested by Hinman and Doty.
Conclusion
No claims allowed.
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/ROBERT H HAVLIN/Primary Patent Examiner, Art Unit 1626
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