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 .
Election/Restrictions
Applicant’s election without traverse of Group I, claims 1, 4, 6–8, 14, 15, 17–19, and 22 in the reply filed on April 29, 2026 is acknowledged.
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 1, 4, 6–8, 14, 15, 17–19, and 22 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.
Claim 1 recites:
1. A method of treating a gas stream to remove methanol and reduce or eliminate formation of dimethyl ether during a regeneration cycle, the method comprising:
directing, during an adsorption cycle of an adsorption process, the gas stream having an initial methanol mole fraction toward a first adsorbent bed of a first adsorber unit, the first adsorbent bed comprising a first adsorbent layer comprising a silica adsorbent, wherein:
an alumina content of the first adsorbent layer is about 3.1 wt.% or less based on a total weight of the first adsorbent layer, and/or
the initial methanol mole fraction is from about 50 ppm to about 1000 ppm. Emphasis added.
Claim 1 is indefinite because “about” is relative terminology that the disclosure fails to define and for which a person of ordinary skill in the art would be unable to ascertain the meaning of. See MPEP 2173.05(b), subsection III, A.
To overcome this rejection, claim 1 could be amended to read:
1. A method of treating a gas stream to remove methanol and reduce or eliminate formation of dimethyl ether during a regeneration cycle, the method comprising:
directing, during an adsorption cycle of an adsorption process, the gas stream having an initial methanol mole fraction toward a first adsorbent bed of a first adsorber unit, the first adsorbent bed comprising a first adsorbent layer comprising a silica adsorbent, wherein:
an alumina content of the first adsorbent layer is
the initial methanol mole fraction is from
Claims 4, 6–8, 14, 15, 17–19, and 22 are indefinite because they depend from claim 1.
Also, claim 8 recites:
8. The method of claim 6, wherein a methanol mole fraction of the gas stream is reduced to about 40 ppm or less, about 30 ppm or less, about 20 ppm or less, about 10 ppm or less, about 5 ppm or less, or about 2 ppm or less prior to the gas stream contacting the second adsorbent layer.
Claim 8 is indefinite because “about” is relative terminology that the disclosure fails to define and for which a person of ordinary skill in the art would be unable to ascertain the meaning of. See MPEP 2173.05(b), subsection III, A.
Claim 8 is also indefinite because it includes narrow and broader ranges in the same claim. See MPEP 2173.05(c), subsection I.
To overcome these rejections, claim 8 could be amended to read:
8. The method of claim 6, wherein a methanol mole fraction of the gas stream is reduced to
Claim 14 recites:
14. The method of claim 6, wherein the second adsorbent layer comprises zeolite 4A, and wherein the zeolite is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr, or Ba.
Claim 14 is indefinite because it is unclear if the zeolite remains 4A (i.e., 4 angstrom pore size) after it is exchanged with Li, Na, K, Mg, Ca, Sr, or Ba. For the purpose of compact prosecution, the zeolite does not necessarily remain 4A after it is exchanged.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention.
Claims 1, 4, and 17–19 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Templeman, US 3,841,058.
Regarding claim 1, Templeman teaches a method of removing impurities, such as methanol, from natural gas, with there being no discussion of dimethyl ether formation during regeneration. See Templeman col. 2, ll. 28–46. The method reads on the claimed “method of treating a gas stream to remove methanol and reduce or eliminate formation of dimethyl ether during a regeneration cycle.”
The method comprises directing natural gas having an initial methanol mole fraction toward a first bed of silica gel, with the natural gas having an initial methanol mole fraction. See Templeman col. 2, ll. 28–46, 4, ll. 19–22. This reads on “directing, during an adsorption cycle of an adsorption process, the gas stream having an initial mole fraction toward a first adsorbent bed of a first adsorber unit, the first adsorbent bed comprising a first adsorbent layer comprising a silica adsorbent.”1
The alumina content of the silica gel is 0% because silica gel lacks alumina.2 This reads on “an alumina content of the first adsorbent layer is about 3.1 wt.% or less based on a total weight of the first adsorbent layer.”
Regarding claim 4, Templeman teaches that the method further comprises regenerating the silica gel of the first bed by passing gas therethrough at an elevated temperature, where the regeneration gas is a portion of the purified natural gas, with there being no discussion of methanol adsorbed in the first bed being converted to dimethyl ether during regeneration. See Templeman col. 2, ll. 28–46, col. 2, ll. 52–58, col. 3, ll. 32–35. This reads on “directing, during the regeneration cycle, at least a portion of the treated gas stream through the first adsorbent bed of the first adsorber unit, wherein a conversion of total methanol adsorbed in the first adsorbent bed into dimethyl ether for the regeneration cycle is less than 7%, wherein the first adsorbent bed is thermally regenerated during the regeneration cycle.”
Regarding claims 17 and 18, Templeman teaches that the gas stream is natural gas, and that the method further comprises forming a liquified natural gas product from the treated natural gas stream after leaving the first bed, as claimed. See Templeman col. 2, ll. 28–46.
Regarding claim 19, Templeman teaches the gas stream is natural gas, and that the method further comprises directing the natural gas stream after leaving the first bed to a pipe (e.g., pipe 22) (a “natural gas pipeline”), as claimed. See Templeman Fig. 2, col. 2, ll. 28–46, col. 3, ll. 32–35.
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.
Claims 6–8 are rejected under 35 U.S.C. 103 as being unpatentable over Templeman, US 3,841,058 in view of Northrop et al., US 2011/0277496 A1.
Regarding claim 6, Templeman teaches the limitations of claim 1, as explained above.
Templeman differs from claim 6 because it is silent as to the first bed comprising a second adsorbent layer comprising a zeolite where the second adsorbent layer is downstream from the silica gel.
But Templeman teaches that the method uses a second bed having a molecular sieve material (downstream of the first bed) to remove carbon dioxide from the natural gas. See Templeman col. 2, ll. 28–46. Also, the silica gel of the first bed is used to remove water and methanol from the natural gas. Id. The first and second beds are in separate vessels. Id.
With this in mind, Northrop teaches a method of purifying natural gas using a single vessel 1 comprising a first adsorbent bed 2 containing a molecular sieve, such as zeolite, that can be downstream of a second adsorbent bed 3 comprising a desiccant material. See Northrop Fig. 1, [0019], [0036]. The first adsorbent bed 2 is used to remove carbon dioxide from the natural gas. Id. at [0036].
It would have been obvious to structure the vessel of Templeman (containing the first bed), in the manner of the vessel 1 of Northrop, with an adsorbent bed of zeolite (for removing carbon dioxide) positioned downstream of the first bed of silica gel (for removing water and methanol), so that the method could utilize a single vessel for removing water, methanol, and carbon dioxide from natural gas, instead of two vessels. It is noted that Templeman teaches that the second bed (for removing carbon dioxide) is regenerated at a lower temperature than the first bed, with the first bed (containing the silica gel for removing water and methanol) being regenerated at a temperature of 250 to 350°C. See Templeman col. 2, ll. 28–46. But Northrop teaches that the zeolite (for removing carbon dioxide) can be regenerated with an overlapping temperature range (250 to 400°C) as the silica gel of Templeman. See Northrop [0039]. Therefore, a person of ordinary skill in the art would have had a reasonable expectation of success in modifying Templeman to provide a zeolite layer in the same vessel as the silica gel of the first bed, with both layers being regenerated at the temperature for regenerating the silica gel.
Regarding claim 7, Templeman teaches that the method further comprises directing the gas stream from the first bed toward a second bed comprising a molecular sieve material for removing carbon dioxide from the natural gas. See Templeman col. 2, ll. 28–46. This reads on “directing the gas stream from the first adsorber unit toward a second adsorbent bed of a second adsorber unit.”
Templeman differs from claim 7 because it is silent as material of the molecular sieve in the second bed. Therefore, the reference fails to provide enough information to teach the molecular sieve comprises a zeolite.
But Northrop teaches a method for removing contaminants, including carbon dioxide, from natural gas, using a molecular sieve material to adsorb carbon dioxide, where the molecular sieve material is made of zeolite. See Northrop [0036]. It would have been obvious for the molecular sieve material in the second bed of Templeman to be zeolite because this would merely represent the selection of a known material based on the suitability of its intended use. See MPEP 2144.07.
Regarding claim 8, Templeman as modified teaches the limitations of claim 6, as explained above.
Templeman as modified differs from claim 8 because it is silent as to the mole fraction of the purified natural gas after contacting the silica gel of the first bed (but before contacting the zeolite for removing carbon dioxide). But Templeman teaches that the silica gel of the first bed is used to remove methanol from the natural gas, so that the mole fraction of the methanol is low enough to avoid formation of solid deposits on cooling. See Templeman col. 1, ll. 13–18. Templeman also teaches that the natural gas has an initial methanol impurity level of 50 v.p.m. Id. at col. 3, ll. 9–11. It would have been obvious to use routine experimentation to determine the optimal methanol mole fraction of the purified gas that has passed through the silica gel to ensure that the solid deposits do not form when the natural gas is cooled. See MPEP 2144.05, subsection II (where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation). A person of ordinary skill in the art would have had a reasonable expectation of success in achieving the claimed range of a methanol mole fraction of less than about 40 ppm because the initial methanol impurity level is slightly above this value (at 50 v.p.m.).
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Templeman, US 3,841,058 in view of Northrop et al., US 2011/0277496 A1 and in further view of Wang et al., US 2018/0056235 A1.
Regarding claim 14, Templeman in view of Northrop teaches the limitations of claim 6, as explained above.
Templeman as modified differs from claim 14 because it is silent as to the zeolite of the second adsorbent layer being zeolite 4A that is exchanged with an element selected from Li, Na, K, Mg, Ca, Sr, or Ba.
But Wang teaches a zeolite material for adsorbing carbon dioxide, where the zeolite is zeolite 4A that is ion exchanged with K. See Wang [0099]. The zeolite material is beneficial because it has fast kinetics and good crystallinity. Id. It would have been obvious to use the zeolite material of Wang as the zeolite of Templeman in view of Northrop to provide a zeolite material with fast kinetics and good crystallinity.
Claim 15 is rejected under 35 U.S.C. 103 as being unpatentable over Templeman, US 3,841,058.
Regarding claim 15, Templeman as modified teaches the limitations of claim 1, as explained above.
Templeman differs from claim 15 because it is silent as to the mole fraction of the purified natural gas after exiting the first bed. But Templeman teaches that the silica gel of the first bed is used to remove methanol from the natural gas, so that the mole fraction of the methanol is low enough to avoid formation of solid deposits on cooling. See Templeman col. 1, ll. 13–18. Templeman also teaches that the natural gas has an initial methanol impurity level of 50 v.p.m. Id. at col. 3, ll. 9–11. It would have been obvious to use routine experimentation to determine the optimal methanol mole fraction of the purified gas that exits the first bed to ensure that the solid deposits do not form when the natural gas is cooled. See MPEP 2144.05, subsection II (where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation). A person of ordinary skill in the art would have had a reasonable expectation of success in achieving the claimed range of a methanol mole fraction of less than about 40 ppm because the initial methanol impurity level is slightly above this value (at 50 v.p.m.).
Claim 22 is rejected under 35 U.S.C. 103 as being unpatentable over Templeman, US 3,841,058 in view of Xu, US 2015/0376527 A1.
Regarding claim 22, Templeman teaches the limitations of claim 1, as explained above.
Templeman differs from claim 22 because it is silent as to whether the gas stream that is purified comprises predominantly carbon dioxide.
But Templeman teaches that the gas stream can be natural gas. See Templeman col. 2, ll. 28–46. Also, Xu teaches that natural gas can be made predominately of carbon dioxide. See Xu [0082].
It would have been obvious for the natural gas of Templeman to comprise predominantly carbon dioxide, depending on the source of natural gas being treated.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Monereau et al., US 2010/0031819 A1 (purification of gas mixture that uses silica gel to remove alcohols); Tyndall et al., US 2007/0028770 A1 (apparatus for air cleaning using silica gel to remove methanol).
Any inquiry concerning this communication or earlier communications from the examiner should be directed to T. BENNETT MCKENZIE whose telephone number is (571)270-5327. The examiner can normally be reached Mon-Thurs 7:30AM-6:00PM.
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T. BENNETT MCKENZIE
Primary Examiner
Art Unit 1776
/T. BENNETT MCKENZIE/Primary Examiner, Art Unit 1776
1 It is noted that Templeman describes the first bed as having an “absorbent material.” But the silica gel is an adsorbent material for methanol. See e.g., Tsybulevski et al., US 2020/0063056 A1 [0077] (silica gel is a conventional methanol adsorbent).
2 See e.g., Dieterle et al., US 2016/0341107 A1 [0015] (silica gel is an amorphous silicon dioxide).
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