Prosecution Insights
Last updated: April 19, 2026
Application No. 18/391,780

METHOD FOR REMOVING NITROGEN OXIDES FROM COMBUSTION FUMES WITH ON-SITE GENERATION OF AMMONIA

Non-Final OA §103
Filed
Dec 21, 2023
Examiner
NASSIRI MOTLAGH, ANITA
Art Unit
1734
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Casale SA
OA Round
3 (Non-Final)
55%
Grant Probability
Moderate
3-4
OA Rounds
2y 10m
To Grant
80%
With Interview

Examiner Intelligence

Grants 55% of resolved cases
55%
Career Allow Rate
335 granted / 614 resolved
-10.4% vs TC avg
Strong +26% interview lift
Without
With
+25.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
29 currently pending
Career history
643
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
58.2%
+18.2% vs TC avg
§102
11.9%
-28.1% vs TC avg
§112
25.2%
-14.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 614 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application is being examined under the pre-AIA first to invent provisions. Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 10/10/2025 has been entered. Claims 1-2, 4-11 are pending and being examined. Claim 3 is canceled. Claims 10-11 are newly added with no new subject matter being introduced. 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 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 pre-AIA 35 U.S.C. 103(a) which forms the basis for all obviousness rejections set forth in this Office action: (a) A patent may not be obtained through the invention is not identically disclosed or described as set forth in section 102, if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains. Patentability shall not be negatived by the manner in which the invention was made. Claims 1-2, 4-7, and 9-11 are rejected under 35 U.S.C. 103(a) as being unpatentable over Becher et al. (US 2005/0025692 A1) in view of Barnicki et al. (US 2006/0149423 A1). Considering claim 1, Becher teaches a method for the control of nitrogen oxides content in the combustion fumes of a power plant (i.e., reduction of nitrogen oxide gases produced by the power source) for the production of electric energy where said combustion takes place comprising the step of producing ammonia in the site of said power plant (Becher, claims 6 and 18). Becher teaches producing hydrogen current by means of electrolysis of water (Becher, paragraph [0034]). Becher teaches producing a nitrogen current by means of separation of nitrogen from air (Becher, paragraph [0033]). Becher teaches forming an ammonia make up gas containing hydrogen (Becher, item 12 of Fig. 2) and nitrogen (Becher, item 10 of Fig. 2) from said hydrogen current and nitrogen current and reacting said make-up gas at a suitable ammonia synthesis pressure (Becher, paragraphs [0026]-[0027] and Fig. 2). Becher teaches reducing nitrogen oxides contained in said combustion fumes using said produced ammonia (Becher, claims 6 and 18). Becher teaches that the ammonia reactor can be load-following according to user-specified criteria (Becher, paragraph [0030]). Becher also teaches that the hydrogen source for the ammonia synthesis is water electrolysis (i.e., use of electric current) (Becher, paragraph [0034]). In addition, claim 1 of the instant case requires the hydrogen for ammonia synthesis to be electrolysis of water. Therefore, it would have been obvious for one of ordinary skill in the art, at the time the invention was made, to set the criteria for the production rate of ammonia in Becher's process to be the availability of electric energy. One of ordinary skill in the art, at the time the invention was made, would have been motivated to do so because electric energy is used in water electrolysis to produce the hydrogen for ammonia synthesis and the rate of ammonia production would depend on the hydrogen produced which would depend on electric energy available. Becher does not explicitly teach that the production rate of ammonia is regulated according to the load of the power plant. However, Barnicki teaches a process for satisfying variable power demand and maximizing a synthesis gas stream; produce electrical power during a peak power demand and produce chemicals during a period of off-peak power demand (Barnicki, Abstract). Barnicki also teaches that this out of phase operational mode allows for the power production zone to maximize electricity output and the chemical producing zone to maximize chemical production with high efficiency (Barnicki, Abstract). Therefore, it would have been obvious for one of ordinary skill in the art, at the time the invention was made, to operate Becher’s process in such a way as to increase ammonia production during electricity off-peak hours and to reduce or stop ammonia production during electricity peak hours. One of ordinary skill in the art, at the time the invention was made, would have been motivated to do so in order to maximize electricity output during peak power demand and to maximize ammonia production during off-peak power demand with a reasonable expectation of success. The claims require producing hydrogen by means of electrolysis of water. Becher teaches producing hydrogen by means of electrolysis of water. Thus, it would be expected that Becher’s production of hydrogen would have the same energy consumption as the claimed production of hydrogen (i.e., less than 1% of the output of the power plant) because both use the same process for hydrogen production. Considering claim 2, Becher teaches that the process of reducing nitrogen oxides is a process of selective catalytic reduction (SCR) (Becher, paragraph [0006]). Considering claim 4, Becher teaches that the nitrogen current is obtained by pressure swing adsorption (PSA) (Becher, paragraph [0033]). Considering claim 5, although Becher teaches an ammonia synthesis pressure of 750 psig (51 bar) (Becher, item 14 of Fig. 2), he does not explicitly teach a pressure range of 80 to 300 bar. However, Becher teaches that a higher pressure results in a higher yield of ammonia with limitations due to safety and cost (Becher, paragraph [0036]). Thus, Becher establishes that the ammonia synthesis pressure is variable and higher pressures within safety and cost limitations result in higher yields of ammonia. Therefore, it would have been obvious for one of ordinary skill in the art, at the time the invention was made, to vary the ammonia synthesis pressure including within the claimed range of 80 to 300 bar in Becher’s process. One of ordinary skill in the art, at the time the invention was made, would have been motivated to do so in order to achieve higher yields of ammonia with a reasonable expectation of success. Considering claim 6, Becher suggests storing excess ammonia in a storage vessel in anhydrous form during said electricity off-peak hours by teaching that ammonia is transferred to a storage container where transients or turndowns are minimized (Becher, paragraphs [0026] and [0029]). Considering claim 7, Becher teaches a method for modification of an installation comprising a unit for reduction of nitrogen oxides from a combustion flue gas wherein an on-site ammonia plant (on-board micro ammonia plant) is added to said installation (Becher, Abstract). Becher teaches a water electrolysis section for producing hydrogen current by means of electrolysis of water (Becher, paragraph [0034]). Becher teaches producing a nitrogen current by means of separation of nitrogen from air (Becher, paragraph [0033]). Becher teaches forming an ammonia make up gas containing hydrogen (Becher, item 12 of Fig. 2) and nitrogen (Becher, item 10 of Fig. 2) from said hydrogen current and nitrogen current and reacting said make-up gas at a suitable ammonia synthesis pressure (Becher, paragraphs [0026]-[0027] and Fig. 2). Becher teaches reducing nitrogen oxides contained in said combustion fumes using said produced ammonia (Becher, Abstract). Becher teaches that the installation is a power plant for the production of electric energy (Becher, claim 6). Becher does not explicitly teach that the production rate of ammonia is regulated according to the load of the power plant. However, Barnicki teaches a process for satisfying variable power demand and maximizing a synthesis gas stream; produce electrical power during a peak power demand and produce chemicals during a period of off-peak power demand (Barnicki, Abstract). Barnicki also teaches that this out of phase operational mode allows for the power production zone to maximize electricity output and the chemical producing zone to maximize chemical production with high efficiency (Barnicki, Abstract). Therefore, it would have been obvious for one of ordinary skill in the art, at the time the invention was made, to operate Becher’s process in such a way as to increase ammonia production during electricity off-peak hours and to reduce or stop ammonia production during electricity peak hours. One of ordinary skill in the art, at the time the invention was made, would have been motivated to do so in order to maximize electricity output during peak power demand and to maximize ammonia production during off-peak power demand with a reasonable expectation of success. The claims require producing hydrogen by means of electrolysis of water. Becher teaches producing hydrogen by means of electrolysis of water. Thus, it would be expected that Becher’s production of hydrogen would have the same energy consumption as the claimed production of hydrogen (i.e., less than 1% of the output of the power plant) because both use the same process for hydrogen production. Considering claim 9, Becher teaches that the process of reducing nitrogen oxides is a process of selective catalytic reduction (SCR) (Becher, paragraph [0006]). Considering claims 10-11, Becher teaches control of NOx production and emissions from power plants which generate a small concentration of NOx in the exhaust gases (Becher, [0005]). Becher teaches small scale generation of ammonia via a micro ammonia plant that controllably produces ammonia that is used to reduce NOx levels in the exhaust streams (Becher, [0013]). Becher teaches producing hydrogen for ammonia synthesis through water electrolysis (Becher, [0034]). Thus, Becher suggests production of hydrogen in an amount needed to produce an amount of ammonia needed to reduce the small concentration of NOx in the exhaust gases of a power plant. In other words, the amount of hydrogen produced is a result effective variable relative to the amount of ammonia needed for a particular amount of NOx produced which is directly related to the rate of power production. Applicant discloses that a large installation such as 300 MW steam turbine power plant needs around 100 kg/h of ammonia for NOx removal (see instant specification, lines 15-17 on page 2). The claims require producing hydrogen by means of electrolysis of water. Becher teaches producing hydrogen by means of electrolysis of water. Thus, it would be expected that Becher’s production of hydrogen would have the same energy consumption as the claimed production of hydrogen because both use the same process for hydrogen production. Therefore, it would be expected that the energy consumption for hydrogen production of Becher’s process would be the same as Applicant’s (i.e., 1 MW of electric power for a power plant having an output of 300 MW) because both use the same process for hydrogen production, both generate an amount of hydrogen needed to produce an amount of ammonia needed for NOx reduction from the power plant. Claim 8 is rejected under 35 U.S.C. 103(a) as being unpatentable over Becher et al. (US 2005/0025692 A1) in view of Barnicki et al. (US 2006/0149423 A1) as applied to claim 9 above, and further as evidenced by Eurelectric (Union of the Electricity Industry – Eurelectric, VGB, “Efficiency in Electricity Generation", July 2003). Considering claim 8, although Becher teaches the installation is a power plant which generates nitrogen oxides (Becher, claims 6 and 18), he is silent as to whether it is a thermal power plant or not. However, as evidenced by Eurelectric on pages 14-15, thermal power plants produce nitrogen oxides whereas non-thermal power plants (power plants using renewable energy sources) do not emit greenhouse gases such as nitrogen oxides. Therefore, since Becher’s power plant produces nitrogen oxides, it would necessarily be expected that Becker’s power plant is a thermal power plant. Moreover, the claim language requires a method for modification of an installation comprising a unit for reduction of nitrogen oxides from a combustion flue gas. The type of installation does not provide any additional limitations to the claimed method. Becher teaches an installation that produces nitrogen oxides, the specifics of the installation do not provide any additional steps to the claimed method. Response to Arguments Applicant’s arguments filed regarding Becher does not disclose the output of the power plant or the relation between such energy consumption and such output have been fully considered but are not persuasive. Becher suggests production of hydrogen in an amount needed to produce an amount of ammonia needed to reduce the small concentration of NOx in the exhaust gases of a power plant. In other words, the amount of hydrogen produced is a result effective variable relative to the amount of ammonia needed for a particular amount of NOx produced which is directly related to the rate of power production. It would be expected that the energy consumption for hydrogen production of Becher’s process would be the same as Applicant’s (i.e., 1 MW of electric power for a power plant having an output of 300 MW) because both use the same process for hydrogen production, both generate an amount of hydrogen needed to produce an amount of ammonia needed for NOx reduction from the power plant. Applicant’s arguments filed regarding neither Becher nor Barnicki disclose or provide any motivation to establish a maximum threshold of the energy consumption for hydrogen production as a function of the output of the power plant have been fully considered but are not persuasive. Becher teaches control of NOx production and emissions from power plants which generate a small concentration of NOx in the exhaust gases (Becher, [0005]). Becher teaches small scale generation of ammonia via a micro ammonia plant that controllably produces ammonia that is used to reduce NOx levels in the exhaust streams (Becher, [0013]). Thus, Becher establishes that ammonia is produced in a small amount (i.e., micro ammonia plant) in an amount needed to control the amount of nitrogen oxides in the combustion fumes of the power plant. The amount of hydrogen production and power used in the production of the hydrogen is directly related to the amount of ammonia needed and the NOx generated by the power plant; the amount of NOx generated is directly related to the power production output. Therefore, Becher does teach a maximum threshold of hydrogen production (i.e., amount needed to produce amount of ammonia needed for NOx reduction). Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANITA NASSIRI-MOTLAGH whose telephone number is (571)270-7588. The examiner can normally be reached M-F 6:30-3:00. 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, Jonathan Johnson can be reached at 571-272-1177. 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. /ANITA NASSIRI-MOTLAGH/Primary Examiner, Art Unit 1734
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Prosecution Timeline

Dec 21, 2023
Application Filed
Sep 19, 2024
Non-Final Rejection — §103
Mar 20, 2025
Response Filed
Apr 04, 2025
Final Rejection — §103
Oct 10, 2025
Request for Continued Examination
Oct 14, 2025
Response after Non-Final Action
Oct 15, 2025
Non-Final Rejection — §103 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

3-4
Expected OA Rounds
55%
Grant Probability
80%
With Interview (+25.7%)
2y 10m
Median Time to Grant
High
PTA Risk
Based on 614 resolved cases by this examiner. Grant probability derived from career allow rate.

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