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 .
Claim Rejections - 35 USC § 112(b)
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 54, 63–68 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.
Claims 54, 65–68 are indefinite because the term “about” is an approximation term which renders the claim indefinite. The term “about” 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. MPEP 2173.05(b)(I).
Claim 54 is indefinite because the term “the range” lacks antecedent basis.
Claim 63 is indefinite because the term “the adsorbent bed” lacks antecedent basis. There are two adsorbent beds as recited in claim 48, and it is unclear which one is the claimed “the adsorbent bed.”
Claim 64 is indefinite because the term “the activated carbon” lacks antecedent basis.
Claim 65 is indefinite because the term “the gas” lacks antecedent basis.
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.
The claims are rejected as follows:
Claims 48, 52, 55, 57–58, 60, 65–67 are rejected under 35 U.S.C. 103 as being unpatentable over Mortensen et al., US 2022/0242727 A1 (“Mortensen”) in view of Bao et al., US 2012/0100063 A1 (“Bao”) and Baksh et al., US 6,340,382 B1 (“Baksh”)
Regarding claim 48:
Mortensen discloses that a method of separating hydrogen gas from an effluent gas of an ammonia cracking reactor operating at an elevated pressure (Mortensen discloses an ammonia cracking reactor 100 that are configured to take ammonia as feed gas via arrow 11 and output product stream gas comprising hydrogen via arrow 12, Mortensen Fig. 1b, [0157] and [0160], Mortensen also discloses its reactor system is operated at a pressure between 2 to 30 bar, Mortensen, [0067], which is consistent with the defined “elevated pressure” being between 5 to 50 bar as defined in the published Spec. [0021]; additionally, Mortensen also discloses a step of feeding product gas comprising hydrogen to separate into an upgraded hydrogen stream and an off-gas stream, Mortensen [0111]–[0112]), in a pressure swing adsorption (PSA) system (Mortensen discloses its upgrading unit may comprising PSA unit, Mortensen [0112].
Mortensen does not disclose that its PSA unit comprising at least two PSA units in parallel, said method comprising:
cooling the effluent gas by heat exchange to produce cooled effluent gas; and
feeding the cooled effluent gas at the elevated pressure to the PSA system to produce a hydrogen product gas and a PSA tail gas;
wherein each PSA unit comprises a feed end, a product end downstream from the feed end and an adsorbent bed located therebetween, the adsorbent bed comprising an upstream layer of non-zeolitic adsorbent that is selectively adsorbent for at least ammonia and a downstream layer of zeolitic adsorbent that is selectively adsorbent for nitrogen.
In the analogous art of hydrogen purification using PSA units, Bao discloses a method of preparing high purity ammonia, Bao discloses a method of obtaining hydrogen-nitrogen mixture by catalytic cracking ammonia and purifying the hydrogen-nitrogen gas mixture using PSA systems, Bao Fig. 1, [0059]. Bao discloses the hydrogen-nitrogen purification could using pressure swing adsorption with twin column structure, Bao [0033]. Bao therefore discloses a PSA unit comprising at least two PSA units in parallel (Bao’s twin column pressure swing adsorption, Bao [0033]), said method comprising:
cooling the effluent gas by heat exchange to produce cooled effluent gas (Bao discloses a step of cooling the gas mixture of hydrogen nitrogen to 70 degree C, Bao [0041]); and
feeding the cooled effluent gas at the elevated pressure to the PSA system to produce a hydrogen product gas and a PSA tail gas (Bao discloses its cooled gas mixture is then led into a hydrogen-nitrogen purifier, which Bao discloses could be pressure swing adsorption unit, Bao [0041] and [0033], Bao discloses its pressure adsorption could remove impurities such as water, carbon dioxide, which would read on the claimed “PSA tail gas” and Bao discloses a hydrogen-nitrogen gas mixture with a purity of at least 99.999%, which would be the claimed “hydrogen product gas”, Bao [0033]);
wherein each PSA unit comprises a feed end (where Bao’s cooled gas mixture enters Bao’s pressure swing adsorption with twin-column structure, Bao [0033]), a product end downstream from the feed end (where Bao’s hydrogen-nitrogen gas mixture with a purity of at least 99.999% leaving Bao’s pressure swing adsorption with twin-column structure, Bao [0033]) and an adsorbent bed located therebetween (Bao discloses its special absorbent of active aluminum oxide, active carbon, zeolite and silica gel located within Bao pressure swing adsorption unit, Bao [0032] and [0033]).
Bao discloses its hydrogen purification system reduces cost, Bao [0045]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use Bao’s pressure swing system in Mortensen for hydrogen purification because it reduced cost and Bao discloses its system is suitable to purify hydrogen and nitrogen from an ammonia cracking reactor.
However, such modification does not disclose that the adsorbent bed comprising an upstream layer of non-zeolitic adsorbent that is selectively adsorbent for at least ammonia and a downstream layer of zeolitic adsorbent that is selectively adsorbent for nitrogen.
In the analogous art of hydrogen purification system using PSA units, Baksh discloses a pressure swing adsorption bed 20 comprising an upstream layer of alumina 211, which is a non-zeolitic adsorbent that is selectively adsorbent for at least ammonia and a downstream layer of zeolitic adsorbent 23 that selectively adsorbent for nitrogen, Baksh Fig. 5, Col. 6, ll. 5–22. Baksh discloses its system provides an improved process for high hydrogen recovery and lower adsorbent inventory, Baksh, col. 1, ll. 5–15. It would therefore have been obvious for one ordinary skill in the art at the time of filing for modified Mortensen’s PSA system to have an adsorbent configuration as disclosed by Baksh for the benefits disclosed above.
Regarding claim 52:
Modified Mortensen discloses that a method according to Claim 48, wherein the non-zeolitic adsorbent selectively co-adsorbs water and/or nitrogen (Baksh discloses its first layer of alumina 21 is for water adsorption, Baksh Fig. 5, col. 6, ll. 5–12.
Regarding claim 55:
Modified Mortensen discloses that a method according to Claim 48, wherein the non-zeolitic adsorbent is an activated carbon (Baksh discloses a layer of activated carbon 22, Baksh Fig. 5, col. 6, ll. 12–14.
Regarding claim 57:
Modified Mortensen does not explicitly disclose that a method according to Claim 56, wherein the activated carbon is pre-treated with acid or base.
However, the published instant disclosure cites prior art references (Water Research vol. 31, p 3414, 1998; and Carbon vol. 37, p 1379, 1999), where the prior art references teach that activated carbons may be pre-treated with acid or base prior to being loaded into the bed, or pre-treated in situ by flowing nitrogen through the layer of activated carbon at an elevated temperature of at least 100° C., e.g. about 150° C., or at least 300° C., e.g. about 340° C. In situ pre-treatment in this way has the effect of reducing oxygen functionality and the acid nature of the surface of the carbon, Spec. [0035]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to include the pre-treat step as disclosed in the prior art cited in the published Spec. for reducing oxygen functionality and acid nature of the surface of the carbon.
Regarding claim 58:
Modified Mortensen does not explicitly disclose that a method according to Claim 56, wherein the activated carbon is pre-treated in situ by flowing nitrogen through the layer of coconut shell at an elevated temperature of at least 150 °C.
However, the published instant disclosure cites a prior art reference (Water Research vol. 31, p 3414, 1998; and Carbon vol. 37, p 1379, 1999), where the prior art teaches that activated carbons may be pre-treated with acid or base prior to being loaded into the bed, or pre-treated in situ by flowing nitrogen through the layer of activated carbon at an elevated temperature of at least 100° C., e.g. about 150° C., or at least 300° C., e.g. about 340° C. In situ pre-treatment in this way has the effect of reducing oxygen functionality and the acid nature of the surface of the carbon, Spec. [0035]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to include the pre-treat step as disclosed in the prior art cited in the published Spec. for reducing oxygen functionality and acid nature of the surface of the carbon.
Regarding claim 60:
Modified Mortensen discloses that a method according to Claim 48, wherein the non-zeolitic adsorbent is activated alumina (Baksh discloses a layer of activated alumina 21, Baksh, Fig. 5, col. 5, ll. 49–53).
Regarding claim 65:
Modified Mortensen does not explicitly disclose that a method according to Claim 48, wherein the effluent gas has from 0% to about 0.5% by volume water and from about 0.1% to about 5% by volume ammonia with the rest of the gas consisting of a mixture of hydrogen and nitrogen in a ratio of about 3:1.
However, Bao discloses that a gas mixture (mainly comprising H.sub.2 and N.sub.2 at a ratio of 3:1, and some other impurities, including H.sub.2O) is first obtained by catalytically cracking the low purity ammonia, Bao [0022]. Bao also discloses an ammonia conversion rate of 99.9%, Bao, [0026], Bao therefore discloses about 0.1 % of not conversed ammonia. Additionally, Bao discloses water impurity in raw ammonia is about 300~600 ppm, Bao [0010], Bao therefore discloses a water impurity range equivalent to 0.03 to 0.06% by volume and therefore falls within the claimed range. It would have been obvious for one ordinary skill in the art at the time of filing for modified Mortensen to have an effluent gas comprising a composition as disclosed by Bao because both Mortensen and Bao use raw ammonia to produce high purity ammonia and they would necessarily have the same gas mixture for purification.
Regarding claim 66:
Modified Mortensen discloses that a method according to Claim 48, wherein the cooled effluent gas is at a temperature in a range from about 150 °C to about 100 °C because Bao discloses a cooled temperature range of 70 to 150 °C, overlapping the claimed range and therefore support a prima facie case of obviousness. MPEP 2144.05(I).
Additionally, the instant disclosure does not teach the claimed cooled temperature range is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
Regarding claim 67:
Modified Mortensen discloses a method according to Claim 48, wherein the elevated pressure of the cooled effluent gas is in a range from about 5 bar to about 40 bar because Bao discloses a pressure of 0.5 to 0.8 MPa (equivalent to 5 to 8 bar), Bao [0061], falls within the claimed range.
Claim 49 is rejected under 35 U.S.C. 103 as being unpatentable over Mortensen in view of Bao and Baksh as applied to claim 48 above, and in further view of Dipendu et al., Characteristics of Ammonia Adsorption on Activated Alumina, 2010 (“Dipendu”).
Regarding claim 49:
Modified Mortensen discloses that a method according to Claim 48, wherein the non-zeolitic adsorbent has a capacity for ammonia of at least 0.01 mmol/g at 0.005 bar and 40*C.
In the analogous art of alumina adsorbent, Dipendu discloses an activated alumina with adsorption capacity for ammonia at 323 K (40° C) and a pressure up to 108 kPa (1.08 bar) to be 1.89 mmol/g, falling within the claimed range, Dipendu, Abstract, p. 5587. It would therefore have been obvious for one ordinary skill in the art at the time of filing for modified Mortensen to use Dipendu’s activated alumina, because Dipendu’s activated alumina has a good adsorption capacity of ammonia.
Claim 53 is rejected under 35 U.S.C. 103 as being unpatentable over Mortensen in view of Bao and Baksh as applied to claim 48 above, as evidenced by Shen et al., Adsorption equilibria and kinetics of Co2 and N2 on activated carbon beads (“Shen”).
Regarding claim 53:
Modified Mortensen does not disclose that a method according to Claim 52, wherein the non-zeolitic adsorbent has a capacity for nitrogen of at least 0.18 mmol/g at 5 bar and 40*C.
However, Baksh discloses a non-zeolite adsorbent of activated carbon, Baksh Fig. 5, col. 6, ll. 5–21. In the analogous art of activated carbon used to adsorb nitrogen, Shen discloses that activated carbon has an adsorption capacity for nitrogen at 500 kPa (5 bar) and 313 K (40 °C) between 0.5 mol/kg (equivalent to 0.5 mmol/g) and 1 mol/kg (equivalent to 0.5 mmol/g), Shen Fig. 8. Shen therefore discloses an adsorption capacity for nitrogen at 5 bar and 313 K within the claimed range.
Claim 54 is rejected under 35 U.S.C. 103 as being unpatentable over Mortensen in view of Bao and Baksh as applied to claim 48 above, as evidenced by Francis, The issue of pH adjustment in acid-washed carbons (“Francis”).
Regarding claim 54:
Modified Mortensen does not disclose that a method according to Claim 48, wherein the non-zeolitic adsorbent has a surface acidity in the range from about pH 6.3 to about pH 9.8.
However, Baksh discloses a non-zeolite adsorbent of activated carbon, Baksh Fig. 5, col. 6, ll. 5–21. Francis discloses activated carbon has a PH greater than 8, Francis p. 2, which falls within the claimed range.
Claims 56 and 64 is rejected under 35 U.S.C. 103 as being unpatentable over Mortensen in view of Bao and Baksh as applied to claim 48 above, and in further view of Moreau et al., US 6,425,939 B1 (“Moreau”).
Regarding claim 56:
Modified Mortensen does not disclose that a method according to Claim 55, wherein the activated carbon is selected from the group consisting of polymer-derived carbon, petroleum pitch carbon, wood-based carbon, coal-based carbon and coconut shell carbon.
In the analogous art of activated carbon used for ammonia adsorption, Moreau discloses activated carbon produced by coconut shell, pine bark, peat, lignite, anthracite, polymers, resins or other primarily organic materials, Moreau, col. 3, ll. 60–64. Moreau discloses such activated carbon comprising a microporous structure that plays an important role in the performance of adsorption process of PSA, Moreau, col. 5, ll. 10–16. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use activated carbon derived from coconut shell carbon for the benefits disclosed.
Regarding claim 64:
Modified Mortensen does not disclose a method according to Claim 48, wherein the activated carbon of the intermediate layer is selected from the group consisting of polymer-derived carbon and petroleum pitch carbon.
In the analogous art of activated carbon used for ammonia adsorption, Moreau discloses activated carbon produced by coconut shell, pine bark, peat, lignite, anthracite, polymers, resins or other primarily organic materials, Moreau, col. 3, ll. 60–64. Moreau discloses such activated carbon comprising a microporous structure that plays an important role in the performance of adsorption process of PSA, Moreau, col. 5, ll. 10–16. It would therefore have been obvious for one ordinary skill in the art at the time of filing to use activated carbon derived from polymer for the benefits disclosed.
Claims 59 and 63 are rejected under 35 U.S.C. 103 as being unpatentable over Mortensen in view of Bao and Baksh, and in further view of Timonen et al., US 2020/0270136 A1 (“Timonen”).
Regarding claim 59:
Modified Mortensen does not disclose that a method according to Claim 55, wherein the activated carbon has an inorganic content of less than 1 wt. %.
However, the published disclose discloses activated carbon with a low inorganic content (less than 0.5 wt% for example) as “low ash” adsorbents, Spec. [0036]. In the analogous art of activated carbon adsorbents, Timonen discloses low ash activated charcoal could significantly improve adsorption capacity, Timonen [0002]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to modify Mortensen’s activated carbon to be low ash activated carbon for a significantly improved adsorption adsorbent.
Additionally, the instant disclosure does not teach the claimed inorganic content range is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
Regarding claim 63:
Modified Mortensen discloses a method according to Claim 48, wherein the adsorbent bed comprises an intermediate layer (22 of Baksh) of activated carbon located between the upstream and downstream layers, Baksh Fig. 5, col. 6, ll. 12–14.
Modified Mortensen does not disclose an inorganic content of less than 1 %.
However, the published disclose discloses activated carbon with a low inorganic content (less than 0.5 wt% for example) as “low ash” adsorbents, Spec. [0036]. In the analogous art of activated carbon adsorbents, Timonen discloses low ash activated charcoal could significantly improve adsorption capacity, Timonen [0002]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to modify Mortensen’s activated carbon to be low ash activated carbon for a significantly improved adsorption adsorbent.
Additionally, the instant disclosure does not teach the claimed inorganic content range is critical to the operation of the claimed invention. Therefore, absent evidence of criticality, this difference fails to patentably distinguish over prior art because it produces a difference in degree rather than in kind. MPEP 2044.05 (III)(A).
Claim 61 is rejected under 35 U.S.C. 103 as being unpatentable over Mortensen in view of Bao and Baksh as applied to claim 60 above, and in further view of White et al., US 2019/0269170 A1 (“White”).
Regarding claim 61:
Modified Mortensen does not disclose that a method as claimed in Claim 60, wherein the activated alumina is pre-treated with base.
In the analogous art of activated alumina adsorbents, White discloses its activated alumina is treated with base, White [0029]. While further discloses its alumina as adsorption surface area greater than about 200 m.sup.2/g and up to about 3000 m.sup.2/g, White [0024]. It would therefore have been obvious for one ordinary skill in the art at the time of filing to further modify Mortensen’s activated alumina to be treated with base for an increased adsorption surface area.
Claim 62 is rejected under 35 U.S.C. 103 as being unpatentable over Mortensen in view of Bao and Baksh as applied to claim 48 above, and in further view of Dahlin et al., US 2010/0096594 A1 (“Dahlin”).
Regarding claim 62:
Modified Mortensen discloses that a method according to Claim 48, wherein non-zeolitic adsorbent is selected from the group consisting of wide pore silica gel, narrow pore silica gel and silicalite.
In the analogous art of gas adsorbents for ammonia gas, Dahlin discloses silicate could be used as adsorbents, Dahlin [0071]. Dahlin discloses silicate could also be used to capture trace metal such as lead, cadmium, arsenic and selenium, sodium, and potassium, Id. It would therefore have been obvious for one ordinary skill in the art at the time of filing to include silicate in modified Mortensen to capture those metals, those metals potentially could exit in raw ammonia if the ammonia is produced from coal or contaminated source, and those metals will cause catalyst poison.
Allowable Subject Matter
Claims 50–51 and 68 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims.
Regarding claim 50:
Modified Mortensen does not disclose a method according to Claim 48, wherein the non-zeolitic adsorbent desorbs at least 10% of adsorbed ammonia after 100 s using a nitrogen purge at 1.4 bar and 40 °C.
It would not have been obvious for one ordinary skill in the art at the time of filing to further modify Mortensen for such limitation because none of the prior art shows or renders such limitation as being obvious.
Regarding claim 51:
Modified Mortensen does not disclose a method according to Claim 48, wherein the non-zeolitic adsorbent desorbs at least 30% of adsorbed ammonia after 600 s using a nitrogen purge at 1.4 bar.
It would not have been obvious for one ordinary skill in the art at the time of filing to further modify Mortensen for such limitation because none of the prior art shows or renders such limitation as being obvious.
Regarding claim 68:
Modified Mortensen does not disclose a method according to Claim 48, wherein the PSA tail gas has a back pressure in a range from about 0.2% to about 20% of the elevated pressure of the effluent gas.
It would not have been obvious for one ordinary skill in the art at the time of filing to further modify Mortensen for such limitation because none of the prior art shows or renders such limitation as being obvious.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to QIANPING HE whose telephone number is (571)272-8385. The examiner can normally be reached on 7:30-5:00 M-F.
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/Qianping He/Examiner, Art Unit 1776
1 Note here that alumina is disclosed by Baksh as an adsorbent for removing water, but alumina is also known in the art as being an effective adsorbent for ammonia because it has acidic surface sites that chemically interact with and adsorb he basis ammonia molecule. See: is aluminum oxide an adsorbent for ammonia - Google Search