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 .
Response to Amendment
This is the response to the amendment filed 12/22/2025 for application 18/685400.
Claims 1-3, and 5-12 are currently pending and have been fully considered.
Claim 4 has been cancelled.
Claim 1 has been amended.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
Claim(s) 1-3, 5 and 8-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over BRIDGES (USPGPUB 2007/0080097) in view of WANG (USPGPUB 2014/0121432).
BRIDGES teaches thermal cracking.
Regarding claim 1, BRIDGES teaches in paragraphs 34-38 and Fig 2 that methane and hydrogen are formed from cracking processes in furnaces.
Feed 3 is sent into one or more furnaces 2 and a cracked gas product is passed by line 5 to be processed in processing section 6.
Cracked gas in line 5 comprises various chemical streams such as ethylene and propylene.
Fuel gas formed is separated and collected in processing section 6.
Fuel gas comprises various streams that may be separated with a demethanizer, a deethanizer, depropanizer and a debutanizer. (C1-C4)
A demethanizer would remove a portion of methane as a methane off-gas export stream.
A plant fuel gas stream may also be collected and recycled back into the furnace.
Streams of hydrogen and methane may be collected in a fuel gas collection drum as a plant fuel gas. The plant fuel gas may be recycled back to one or more furnaces.
The plant fuel gas may be considered the methane off-gas.
WANG teaches that an ethylene plant comprises both liquid cracking furnaces and gaseous cracking furnaces.
It would be obvious to one of ordinary skill in the art to combine the methane off-gas streams from both liquid cracking furnaces and gaseous cracking furnaces given that BRIDGES teaches that gas streams may be from multiple furnaces.
BRIDGES teaches in paragraphs 29-31 that applying the process that BRIDGES teaches, such as to an ethylene plant with multiple furnaces of both liquid cracking furnaces and gaseous cracking furnace, would allow for recycling of fuel gas as well as increased number of final products that may be used.
BRIDGES teaches in paragraph 36 that streams of hydrogen and methane or mixtures of less pure hydrogen may be sent to the fuel gas drum to produce plant fuel gas 8.
Generally, differences in concentration or temperature will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here 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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Having different streams of methane and hydrogen from different furnaces sent to the fuel gas drum would be well within one of ordinary skill in the art to the contrary.
BRIDGES further teaches in paragraph 52 that various methane and hydrogen streams may be passed into a fuel gas drum to produce the plant fuel gas.
It would be obvious to one of ordinary skill in the art that given various methane and hydrogen streams may be used to produce the plant fuel gas, that another hydrogen stream may further be added to the plant fuel gas.
WANG further teaches in paragraph 26 the motivation to add a hydrogen stream to the feed to a cracking furnace.
WANG teaches that hydrogen is beneficial in slowing down the production of coke in the cracking furnaces.
One of ordinary skill in the art would add hydrogen to a stream that is fed into the cracking furnace with a reasonable expectation of success.
Therefore, the invention as a whole would have been prima facie obvious to one of ordinary skill in the art at the time of the invention.
Regarding claim 10, WANG teaches in paragraph 7 one gas cracking furnace.
However, it has been held that duplication of parts has no patentable significance unless a new and unexpected result is produced. See In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960).
Regarding claim 11, the process for processing is taught in paragraphs 34-38 and Fig 2 of BRIDGES.
Gas 5 is quenched to separate liquid fuel oil and pyrolysis gasoline from the rest of gas 5. The rest of gas 5 is compressed to separate C5 and heavier hydrocarbons. Gas 5 is then processed in a refrigeration unit to separate high purity hydrogen stream.
Regarding claim 2, WANG teaches in paragraph 7 an ethylene plant comprises liquid cracking furnaces and gas cracking furnaces. The liquid cracking furnaces may use a feed of naphtha. The gas cracking furnaces are taught to use feedstocks of generally ethane, propane, C4 alkanes, etc., which are fed into the furnace in the gas phase.
Regarding claim 3, BRIDGES teaches a plant fuel gas that may be recycled back into the furnaces.
Regarding claim 12, WANG teaches in paragraph 7 that liquid cracking furnaces may use a feed of naphtha. The gas cracking furnaces are taught to use feedstocks of generally ethane, propane, C4 alkanes, etc., which are fed into the furnace in the gas phase. BRIDGES teaches a plant fuel gas that may be recycled back into the furnaces.
Regarding claim 5, BRIDGES further teaches in paragraph 52 that various methane and hydrogen streams may be passed into a fuel gas drum to produce the plant fuel gas. A less pure hydrogen gas stream separated in processing section 6 may be sent to the fuel gas drum.
WANG further teaches in paragraph 26 the motivation to add a hydrogen stream to an input to a cracking furnace.
WANG teaches that hydrogen is beneficial in slowing down the production of coke in the cracking furnaces.
Regarding claim 8, BRIDGES teaches in paragraphs 36-37 that the plant fuel gas comprises up to 28 mol% of hydrogen. A portion of the plant fuel gas may be exported out.
In the case where the claimed ranges "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).
Regarding claim 9, WANG further teaches in paragraph 26 the motivation to add a hydrogen stream to the feed to a cracking furnace.
WANG teaches that hydrogen is beneficial in slowing down the production of coke in the cracking furnaces.
"[W]here 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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Therefore, the invention as a whole would have been prima facie obvious to one of ordinary skill in the art at the time of the invention.
Claim(s) 6-7 is/are rejected under 35 U.S.C. 103 as being unpatentable over BRIDGES (USPGPUB 2007/0080097) in view of WANG (USPGPUB 2014/0121432) as applied to claims 1-5 and 8-12 above, and further in view of FONG et al. (US 5152976).
The above discussion of BRIDGES in view of WANG is incorporated herein by reference.
Regarding claim 6, BRIDGES teaches in paragraph 36 processing to separate an individual high purity hydrogen stream.
FONG et al. teach a process for producing high purity hydrogen gas stream from an offgas stream by using pressure swing adsorption for purification.
It would be obvious to one of ordinary skill in the art to use a known technique to collect a high purity hydrogen gas stream in the processing step in BRIDGES.
The motivation to use pressure swing adsorption is to collect a high purity hydrogen gas stream.
Regarding claim 7, the rate of the flow of pressure swing adsorption and the rate of the flow of the second methane off-gas stream appear to be a matter of design choice and it appears that the rate of flow does not appear to solve any particular problem and it appears that the invention would perform equally well with a ratio outside the rates claimed.
"[W]here 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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Therefore, the invention as a whole would have been prima facie obvious to one of ordinary skill in the art at the time of the invention.
Response to Arguments
Applicant's arguments filed 12/22/2025 have been fully considered but they are not persuasive.
Applicant argues that BRIDGES do not teach a first methane off-gas stream from a liquid cracking furnace, with a hydrogen content of 10 vol% to 20 vol% and a second methane off-gas stream, from a gas cracking furnace, with a hydrogen content of 67 vol -77 vol%.
This is not persuasive as BRIDGES teaches a thermal cracking process. The process comprises supplying feed to one or more furnaces to produce a cracked gas product. The cracked gas product is sent to a processing section where a plant fuel gas stream may be collected and recycled back into the furnace.
WANG is relied on to teach that it is known in the art to utilize both liquid cracking furnaces and gas cracking furnaces.
Regarding the use of 2 different hydrogen content for the first methane off-gas stream and the second methane off-gas stream, differences in concentration generally will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such concentration or temperature is critical. "[W]here 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." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Having different streams of methane and hydrogen from different furnaces sent to the fuel gas drum would be well within one of ordinary skill in the art to the contrary. Applicant has not provided evidence indicating such concentration is critical.
Applicant argues that BRIDGES teaches a very specific range in paragraph 53 for the plant fuel gas.
This is not persuasive as paragraph 53 of BRIDGES is with reference to an example. BRIDGES also teaches a broader disclosure in paragraph 37 that although there is a general range, that plant fuel gas covers a widely varying mixture of hydrogen and methane.
Applicant argues that WANG teaches the addition of hydrogen to the feed and not to the fuel.
This is not persuasive as BRIDGES further teaches in paragraph 52 that various methane and hydrogen streams may be passed into a fuel gas drum to produce the plant fuel gas. Further adding hydrogen streams to the plant fuel gas would be well within one of ordinary skill in the art if the desired concentration of hydrogen was not reached.
The reference to WANG refers to the explicit teaching that WANG teaches of adding hydrogen to a feed to a cracking furnace. WANG teaches that the hydrogen is beneficial in slowing down the formation of coke.
BRIDGES on its own already teach that hydrogen and methane streams are added to form the plant fuel gas.
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.
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/MING CHEUNG PO/ Examiner, Art Unit 1771
/ELLEN M MCAVOY/ Primary Examiner, Art Unit 1771