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 § 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 1, 15, and 17–19 are rejected under 35 U.S.C. 103 as being unpatentable over Templeman, US 3,841,058 in view of Hufton et al., US 2010/0011955 A1 and in further view of Tsybulevski et al., US 2020/0063056 A1, as evidenced by Salciccioli et al., US 2017/0022129 A1.
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. 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.”
The method further comprises:
Directing, during the regeneration cycle, at least a portion of the treated natural gas stream (purified by another set of vessels) through the first bed, with the first bed being thermally regenerated during the regeneration cycle. See Templeman col. 2, ll. 36–57, col. 3, ll. 60–65.
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 the first adsorbent bed is thermally regenerated during the regeneration cycle.”
Templeman differs from claim 1 because it is silent as to the alumina content of the silica gel. Therefore, the reference fails to provide enough information to teach the silica gel having an alumina content of 3.1 wt.% or less based on a total weight of the adsorbent. But Hufton teaches that commercial grade silica gel, conventionally used in adsorption of gases, has an alumina content of 1%. See Hufton [0036]. It would have been obvious for the silica gel of Templeman to have an alumina content of 1% because this is the alumina content of commercial grade alumina used in adsorption.
Templeman also differs from claim 1 because it is silent as to the initial mole fraction being 100 to 1,000 ppm, as claimed. Instead, the reference provides a non-limiting example where the methanol content in the natural gas is 50 v.p.m. See Templeman col. 3, ll. 9–11.
But Templeman teaches that the purified natural gas is sent downstream to a liquefication plant. See Templeman col. 3, ll. 29–31. With this in mind, Tsybulevski teaches that methanol is conventionally injected into natural gas before any kind of cryogenic treatment is performed to prevent hydrate formation. See Tsybulevski [0002]. Tsybulevski teaches a similar method of adsorbing methanol from natural gas for recovery—and teaches a process where the natural gas has a methanol content of 750 ppm. Id. at [0034].
It would have been obvious to use routine experimentation to determine the optimal initial methanol mole fraction in the natural gas to be processed by the method of Templeman depending on the amount of methanol required to be injected into the natural gas to prevent hydrate formation. A person of ordinary skill in the art would have had a reasonable expectation of success in achieving the claimed range of 100 to 1,000 ppm, because Tsybulevski teaches an initial mole fraction of 750 ppm. 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).
The limitation of—“a conversion of total methanol adsorbed in the first adsorbent bed into dimethyl ether for the regeneration cycle is less than 7%”—is now addressed. Salciccioli teaches that the chemical reaction of methanol dehydration to produce dimethyl ether is commonly produced by acid catalyzed dehydration of methanol using a catalyst, such as silica gel, at a temperature of about 250° to 700°C, preferably 350°C to 500°C. See Salciccioli [0042].
In Templeman as modified, during regeneration, the first bed of silica gel with 1% alumina (loaded with methanol) can be heated to a temperature of 250°C (as the temperature range is between 250° and 350°C). See Templeman col. 2, ll. 28–46, col. 4, ll. 15–22. Templeman is silent as to the percentage of methanol converted to dimethyl ether (DME) during regeneration.
Also, the Applicant’s specification teaches Example 1 where adsorbent A of silica gel with an alumina content of 3.1 wt% is loaded with methanol and regenerated at a temperature of 270°C—producing a conversion of methanol to DME of 7.32%. See Spec. [0104]–[0107]. Further, in Example 2, adsorbent B of silica gel with an alumina content of 0.6 wt% is loaded with methanol and regenerated at 270°C—producing a conversion of methanol to DME of 0.28%. Id.
Because the operating conditions of Templeman as modified are similar to the examples in the Applicant’s disclosure (and close to Example 2 where conversion to DME is 0.28%), the process of Templeman as modified would be expected for the conversion of total methanol adsorbed in the first bed into dimethyl ether for the regeneration cycle to be less than 7%, as claimed.
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.).
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.
Claims 6–8 are rejected under 35 U.S.C. 103 as being unpatentable over Templeman, US 3,841,058 in view of Hufton et al., US 2010/0011955 A1 in view of Tsybulevski et al., US 2020/0063056 A1 and in further view of Northrop et al., US 2011/0277496 A1, as evidenced by Salciccioli et al., US 2017/0022129 A1.
Regarding claim 6, Templeman as modified 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).
Claim 14 is rejected under 35 U.S.C. 103 as being unpatentable over Templeman, US 3,841,058 in view of Hufton et al., US 2010/0011955 A1 in view of Tsybulevski et al., US 2020/0063056 A1 in view of Northrop et al., US 2011/0277496 A1 and in further view of Wang et al., US 2018/0056235 A1, as evidenced by Salciccioli et al., US 2017/0022129 A1.
Regarding claim 14, Templeman as modified 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.
But Wang teaches a zeolite material for adsorbing carbon dioxide, where the zeolite is zeolite 4A. 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 22 is rejected under 35 U.S.C. 103 as being unpatentable over Templeman, US 3,841,058 in view of Hufton et al., US 2010/0011955 A1 in view of Tsybulevski et al., US 2020/0063056 A1 and in further view of Xu, US 2015/0376527 A1, as evidenced by Salciccioli et al., US 2017/0022129 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.
Response to Arguments
35 U.S.C. 112(b) Rejections
The Examiner withdraws the previous 35 U.S.C. 112(b) rejections in light of the amendments.
35 U.S.C. 102 & 103 Rejections
Applicant’s arguments with respect to the pending claims have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
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.
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
