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 Status
The claims are not amended, but newly added Claim 25 combines former Claim 6 with Claim 1.
Response to Arguments
Applicant's arguments filed 12/11/25 have been fully considered but they are not persuasive.
The remarks argue the following:
Applicant respectfully disagrees with the assertion that it would have been obvious "to send the tail stream of O'Connell, back to a plasma reactor, as taught by Selinger." In particular, the Office Action notes that the tail gas that is supposedly sent back to Selinger's plasma reactor includes H2S. O'Connell already discloses processing effluent gas that includes H2S. In this regard, O'Connell describes a hydrogenation reactor 130 that produces "a hydrogenation effluent 36" that "can include H2S, H2O, C02, H2 and combinations of the same." O'Connell, [0041]. O'Connell further describes processing the hydrogenation effluent 36 in a process desuperheater 145 followed by an absorber unit 150 to produce "a waste gas stream 56."O'Connell, Fig. 1. O'Connell further describes processing the "waste gas stream 56" in an oxidizer 165 to produce "a sulfur dioxide waste stream 68."O'Connell, [0047]. As an alternative to further processing the "waste gas stream 56," O'Connell states that "waste gas stream 56 can be vented to atmosphere where permitted by governmental regulations."O'Connell, [0046].
In view of the foregoing description in O'Connell, a person of ordinary skill in the art (POSITA) would have recognized that O'Connell already describes processing waste gas effluents that include H2S using an oxidizer to produce sulfur dioxide waste streams or venting such effluents to atmosphere where permitted. Because O'Connell already describes processing waste gas streams, the POSITA would have found no need to modify O'Connell to send the effluent to Selinger's plasma reactor, specifically a non-thermal plasma reactor, for further processing.
The remarks are respectfully not persuasive. O’Connell explains that the waste gas stream 56, which contains H2S, sulfur contaminants and various other wastes (para. 46) is finally processed in any oxidizer “capable of combusting sulfur-containing compounds to produce SO2” (para. 47). This SO2 can then be vented to the air (para. 47).
Selinger explains in their background, that current technologies used to decontaminate sulfur exhaust are known to produce SO2 as an end-product (para. 4, 5). SO2 gas is however a major component of acid rain anda source of other issues (para. 4, 5). As a consequence to this, Selinger describes processing H2S by avoiding the final production of SO2 (para. 7, 8). Therefore, Selinger replaces the oxidizer of O’Connell with a plasma device in order to produce less SO2 with the H2S product.
Next, the remarks argue the following:
Moreover, the POSITA would have recognized that the proposed modification would not have resulted in the claimed invention. Claim 1 recites "converting H2S in the NTP reactor into hydrogen (H2) and elemental sulfur." O'Connell describes a sulfur condenser 115, which "caus[es] the elemental sulfur vapor present in waste heat boiler effluent 20 to condense as condensed liquid sulfur stream 24."O'Connell, [0029]. O'Connell states that the "liquid sulfur stream 24 contains greater than 95 wt % elemental sulfur, alternately greater than 97 wt % elemental sulfur, alternately greater than 99 wt % elemental sulfur, alternately greater than 99.5 wt % elemental sulfur, alternately greater than 99.9wt% elemental sulfur."O'Connell, [0029]. O'Connell further states that "non-condensed gas stream 28" which "contains those components present in waste heat boiler effluent 20 that do not condense in sulfur condenser 115""contains less than 1% by volume elemental sulfur vapor."O'Connell, [0030]. Thus, the POSITA would recognize that there simply is not enough sulfur vapor in the effluent 20 that would warrant a significant modification of O'Connell to include Selinger's plasma reactor. In other words, the POSITA would recognize the extra work and greater expense needed to include Selinger's plasma reactor in O'Connell's design and to flow the waste gas stream 56 to Selinger's plasma reactor instead of (or in addition to) O'Connell's oxidizer 165 would be for no apparent reason because the stream to be processed lacks a meaningful quantity of sulfur vapor. M.P.E.P. 2143, I, A, Example 3.
For the foregoing reasons, Applicant respectfully requests that the rejection of independent claim 1 in view of O'Connell, Selinger and Liu be withdrawn. Portions of Reed and Norjkhaus have not been cited as remedying the deficiencies of the proposed combination of O'Connell,
Selinger and Liu. Accordingly, Applicant respectfully requests that the rejection of the dependent claims also be withdrawn.
The remarks are not persuasive. As argued above, the process of feeding H2S to produce SO2 was described as undesirable in Selinger. As a solution to this, Selinger explains feeding the H2S stream to a plasma reactor, which produces H2 and S2 (Selinger, title).
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.
Claim(s) 1, 3, 5 is/are rejected under 35 U.S.C. 103 as being unpatentable over O’Connell (US Pub.: 2017/0173527) and in view of Selinger (US Pub.: 2005/0191237) and in view of Liu (CN 210528467).
O’Connell describes a method for sulfur processing, reduction and recovery (para. 1, 2) using a process that first feeds a sulfur and hydrogen sulfide-containing gas stream, or “acid gases” (para. 9) to a furnace/burner (para. 11). This furnace/burner is part of a system (see Fig. 1 or 2). Either of these systems can be considered a sulfur recovery unit. Air and the acid gases fed to the furnace/burner are reacted (para. 24). Some of the H2S is reacted with SO2 to make S and water (para. 24, equation 2). Following this, O’Connell teaches that this stream is fed to a sulfur condenser 115 (para. 29).
O’Connell does not specifically teach that the sulfur condenser is made up of heat exchangers.
Non condensed gas from the sulfur condenser is then fed to a hydrogenation reactor (130) (para. 33 and Fig. 1 or Fig. 2), which converts elemental sulfur and SO2 into H2S (para. 33). From the sulfur condenser, the stream passes to a process desuperheater, 145, which reduces the temperature of the stream to produce condensed water and cooled effluent (para. 41). The process desuperheater, 145, can be considered a quench tower. Condensed water from this stream condenses in the process desuperheater and the cooled effluent is separated from this water stream (para. 41).
This stream is fed to an absorbing unit (150) (para. 45) and the gas effluent is then passed to an oxidizer, 165, which includes a free-flame thermal oxidizer that comprises a catalyst used to combust sulfur-containing gases to create SO2 (para. 47).
O’Connell does not teach that the thermal oxidizer used at the end of the process is a non-thermal plasma reactor.
As to use of a non-thermal plasma reactor at the end of their system, Selinger describes a process and apparatus for converting hydrogen sulfide into hydrogen and sulfur (title). In their background, Selinger explains that conventional sulfur recovery processes, such as Claus processes, are known to use a process of removing sulfur that includes a combustion step at the end where the tail gas is incinerated (para. 5). However, there are numerous disadvantages to this (para. 5, 6, 8). Use of other means to reduce the pollutants in these streams, include use of plasma reactors (para. 9). These are known to be effective in dissociating pollutants, to include H2S (para. 10, 11). Therefore, in their process, Selinger describes processing a H2S-containing stream by use of a number of process features, to include use of several separation steps (para. 19, 20, 21, 22) and absorption step and dissociation steps (para. 27, 30). The dissociation step occurs with the hydrogen sulfide (para. 30) and thermally decomposes it using plasma conditions to break down the H2S (para. 30, 31, 32).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to send the tail stream of O’Connell, back to a plasma reactor, as taught by Selinger for use in dissociating pollutants and decompose it to break down H2S.
As to the use of heat exchangers in the sulfur condenser, Liu teaches a process for processing H2S gas (“summary of the invention”, para. 1). The process uses an oxidation step, followed by cooling and condensing sulfur (page 2, “summary of the invention”, para. 3). The sulfur condensing and collecting device using heat exchanger (page 2, last para).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ a heat exchanger in the sulfur condenser, as taught by Liu for use with the sulfur processor of O’Connell and Selinger because heat exchangers are known to effectively condense sulfur in a sulfur processing exhaust stream.
As to Claim 3, O’Connell teaches that the gas stream contains H2S and CO2 (para. 18, 19) and this stream is fed to a burner with catalytic converters (para. 25).
As to Claim 5, Selinger teaches that the dissociation step occurs with the hydrogen sulfide (para. 30) and thermally decomposes it using plasma conditions to break down the H2S (para. 30, 31, 32).
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over O’Connell, Selinger and Liu as applied to claim 1 above, and further in view of Reed (CA 1168024).
O’Connell teaches that the stream is fed to a hydrogenation reactor (130) and then feed this to a desuperheater or an exhaust gas cooler (see above). O’Connell does not specifically teach that after the hydrogenation reactor, the stream is then fed to a cooler heat exchanger prior to feeding it to the quench tower.
Reed describes a sulfur recovery process (abstract) that feeds a sulfur-containing stream into a furnace (page 13, lines 11-13, combustion zone) along with an air stream (page 13, lines 15-17). After this, the system feeds a stream from the hydrogenation reactor 106 (page 13, lines 29-30, Fig. 4) to a gas cooler (109), which uses heat exchange to cool the stream to achieve a H2S-laden stream (page 14, lines 12-15). This stream is then fed to a quench tower to further cool the stream and condense any water in the stream (page 14, lines 17-21). The quenching step reduces the water content in the gas stream (page 14, lines 24-28).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to add a gas cooler upstream to a quenching device, as taught by Reed for use with O’Connell, Selinger and Liu because Liu explains that the combination of cooler and quench water further removes water from the gas stream to separate out the H2S in the gas.
As to the overhead gases comprising gas without water vapor removed in the quench tower, although some water is removed in the quench tower, Reed explains that some of the ga still contains some water vapor (page 14, lines 26-29). Therefore, the gaseous stream leftover still contains some water vapor and that stream can be considered the overhead gas stream.
Claim(s) 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over O’Connell, Selinger and Liu as applied to claim 5 above, and further in view of Nojkhaus (RU 2772765).
The references do not teach that the N2 loading in the NTP reactor and that this stream has an increased flow rate.
Nojkhaus describes a method and device for processing hydrogen sulfide (abstract). The process feeds an oxidized gas mixture into a Claus (Klaus) furnace (abstract). The reference explains that use of oxygen enrichment is a well-known economical and reliable way to debottle neck existing Claus sulfur plants with minimal capital investments (page 2, lines 7-10). This can be done using an air separation unit (page 6, lines 3-5). In some embodiments, some of the ambient air is replaced with pure oxygen (page 5, para. 5).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the N2 loading in this stream would be less than the N2 loading in an ambient air stream because this enriched air stream contains a portion of pure oxygen.
As to the flow rate, Nojkhaus explains that by increasing the oxygen enrichment in the stream, the flow of gas is increased (page 2, lines 7-10).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention that the flow rate of the tail gas stream is higher since Nojkhaus explains that the increased oxygen reduces bottlenecking.
Furthermore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to employ an oxygen air stream enriched using an air separation unit, as taught by Nojkhaus for use with the process of O’Connell, Selinger and Liu because use of these devices is known to debottle neck Claus sulfur plants with minimal capital investment.
Allowable Subject Matter
Claim 25 is allowed.
The following is an examiner’s statement of reasons for allowance: Selinger explains replacing the oxidizer with a plasma reactor, but none of the references describe use of a plasma reactor followed by a thermal oxidizer.
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Conclusion
THIS ACTION IS MADE FINAL. 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 SHENG HAN DAVIS whose telephone number is (571)270-5823. The examiner can normally be reached 9-5:30.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Fung Coris can be reached at 571-270-5713. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/SHENG H DAVIS/Primary Examiner, Art Unit 1732 January 29, 2026