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 .
DETAILED ACTION
Response to Amendment
1. The amendment filed on 02/23/2026 has been made of record and entered.
Claims 5, 7, & 19 have been amended.
Claims 1-30 are currently pending in this application.
Status of Withdrawn Claim(s)
2. Claims 19-29 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention(s), there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 10/23/2025.
*Proper status identifiers of withdrawn claims should be (Withdrawn-Currently Amended).
Claim Rejections - 35 USC § 102(a)(1)
3. 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.
Claim(s) 1-3 s/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Kern (US 2019/0337804 A1), hereinafter “Kern”.
The claimed invention relates to a process for producing nitric acid, the process comprising:
(a) mixing compressed air, ammonia, and gaseous oxygen to obtain a gaseous mixture; (b) catalytically oxidizing the ammonia in a first reactor to obtain an ammonia oxidized
stream comprising nitric oxide;
(c) catalytically oxidizing the ammonia oxidized stream comprising nitric oxide in a second reactor to obtain a nitric oxide oxidized stream comprising nitrogen dioxide;
(d) cooling the nitric oxide oxidized stream comprising nitrogen dioxide to obtain a cooled gaseous stream; and
(e) absorbing the cooled gaseous stream in water to obtain nitric acid and a tail gas; wherein energy is recovered from said (b), (c), and (d) (as recited in the instant claim 1).
Kern discloses a process for producing nitric acid comprising:
oxidizing ammonia with oxygen in a presence of catalyst to provide a process gas containing nitrogen monoxide in an oxidation reactor;
supplying oxygen-containing gas to the nitrogen monoxide; and
oxidizing the nitrogen monoxide in a second reactor to provide nitrogen dioxide that is reacted with water in an absorption apparatus to produce nitric acid, nitrous acid, and/or solutions of nitrates and/or nitrites, wherein the second reactor is a container charged with a catalyst for oxidizing the nitrogen monoxide to provide the nitrogen dioxide, wherein the second reactor is at least one of:
positioned between the oxidation reactor and the absorption apparatus with respect to a flow direction of the process gas such that the process gas traverses the second reactor, or
positioned parallel with the absorption apparatus and connected to the absorption apparatus such that the process gas traverses the second reactor (see p. 6, claim 22).
Regarding claim 1, step (a) and step (b), Kern teaches a process for producing nitric acid comprising “mixing compressed air, ammonia, and gaseous oxygen to obtain a gaseous mixture” and “catalytically oxidizing the ammonia in a first reactor to obtain an ammonia oxidized stream comprising nitric oxide” as claimed (see col. 6, claim 22, lines 1-6 and p. 4, [0066]). Compressed air is used in the disclosed process (see [0081] on p. 4). Specifically, Kern teaches to use a modified two-pressure plant for producing the nitric acid, which comprises NH3 oxidation reactor supplied via a compressor with combustion air. Gaseous ammonia is mixed with the combustion air and this mixed gas is then supplied to the NH3 oxidation reactor.
Regarding claim 1, step (c), “catalytically oxidizing the ammonia oxidized stream comprising nitric oxide in a second reactor to obtain a nitric oxide oxidized stream comprising nitrogen dioxide” is disclosed at p. 6, claim 22, lines 7-8.
Regarding claim 1, step (d), “cooling the nitric oxide gaseous stream comprising nitrogen oxide to obtain a cooled gaseous stream” is disclosed at p. 5, [0081].
Regarding claim 1, step (e), “absorbing the cooled gaseous stream in water to obtain nitric acid and a tail gas” is disclosed at p. 5, [0081] and p. 4. [0068].
With respect to the claim limitation on “wherein energy is recovered from said (b), (c), and (d) in the instant claim 1, this is inherently met by the reference in view of the same process steps disclosed and claimed.
Regarding claims 2 & 3, oxidation catalyst is used in the oxidation step of the disclosed process (see p. 6, claim 22, line 1; p. 3, [0042] - [0055]; p. 4, [0067], and p. 7, claim 35, line 8 & line 14).
The claimed process does not appear to distinguish from the disclosed process thus the instant claims are anticipated by the reference.
Claim Rejections - 35 USC § 103
4. 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.
Claim(s) 4-18 & 30 is/are rejected under 35 U.S.C. 103 as being unpatentable over Kern (US 2019/0337804 A1), as applied to claims 1-3 above, and further in view of Warner (US 2021/0300759 A1) and EP 4 095 093 A1, hereinafter “EP ‘093”.
Kern discloses a process for producing nitric acid as set forth in the precedent paragraph, except for the following differences.
Regarding claims 4, 5, & 9, the instant claims further define "the high-pressure supercritical steam is at a pressure of 220-250 bars and a temperature of 550-600°C".
Kern does not appear to teach the claimed “high-pressure supercritical steam” limitation. However, it would have been prima facie obvious to a skilled person in the art (at the time the invention was made) to modify the process of Kern in view of Warner. Warner fairly teaches a similar process for producing nitric acid, using an ammonia burner, which is operated at an elevated pressure, such as at a pressure between about 5.0 bara and 20.0 bara to form a stream comprising nitric oxide (see page 3, [0036]). The oxygen supply line comprises an energy recovery system, which comprises a means for pressurizing the oxygen containing fluid in the liquid state, to a pressure of at least 10 bara, in particular to at least 50 bara, more in particular to at least 100 bara, and even more between 150 bara and 250 bara (see page 3, [0040] & page 4, [0048]). The disclosed pressure range of between 150 and 250 bars appears to be overlapping with the instant claimed pressure range of 220-250 bara.
Regarding claims 6, 7, & 10, the instant claims further define "the low-pressure steam is at a pressure of 5-10 bars and a temperature of 250-300°C".
Kern does not appear to teach the claimed “low-pressure steam” limitation. However, it would have been prima facie obvious to a skilled person in the art (at the time the invention was made) to modify the process of Kern in view of Warner. Warner teaches expanding the hot, pressurized gaseous oxygen containing fluid over a turbine, thus generating a cooled oxygen containing fluid stream having a pressure of between 10 and 30 bara and a temperature of between -180°C and 25°C., and particularly recovering power, i.e. electricity, by operationally coupling the turbine to a generator (see page 7, [0095]).
The claimed temperatures of 550-600°C and 250-300°C (as recited in the instant claims 5 & 6) are not disclosed in the above references.
It would have been prima facie obvious to a person within the ordinary skilled in the art (at the time the invention was made) to find an optimum temperature range that is effective and workable for carrying out the process of the reference, in view of In re Aller and In re Boesch. It is also known in EP ‘093 to produce nitric acid at a temperature range of 450-700°C (see EP ‘093 at col. 15, claim 1, & abstract) and optimization of the temperature range of this reference to a workable range, such as the claimed temperature ranges is prima facie obvious to a person skilled in the art.
Regarding claims 8, 11, 16, & 17, the instant claims further define "at least a part of the energy from said (b) is used to heat the tail gas to obtain a hot tail gas at a temperature of 400-700°C".
Even though Warner does not teach the claimed temperature range, it would have been obvious to heat the tail gas at the claimed temperature range because it is known in EP ‘093 to carry out the catalytic decomposition step at a temperature of between 450°C and
700°C in a process for production of nitric acid (see EP ‘093 at col. 15, claim 1, & abstract).
Regarding claim 12, Warner teaches that the heat is recovered from a heat exchanger and the working fluid in the heating loop is circulated by a circulation pump (see page 10, [0130] & Example 2).
Regarding claims 13-15, Warner teaches multiple turbines (first, second, and third) and each one is coupled to a generator (see page 8, [0118]- page 9, [0119] & Example 1).
Regarding claims 13-15, Warner teaches multiple turbines (first, second, and third) and each one is coupled to a generator (see page 8, [0118]- page 9, [0119] & Example 1).
Regarding claim 18, Warner teaches the gaseous oxygen obtained from a water hydrolysis process for hydrogen production (see page 4, [0043]).
Regarding claim 30, Warner teaches the electricity may be supplied to one or more front end or upstream processes of the nitric acid production process, such as the electrolysis-based production of hydrogen gas in an ammonia production process (see page 2, [0018]).
Response to Applicants’ Arguments
5. Applicants’ remarks filed on 02/23/2026 have been fully reviewed and considered, the arguments are not deemed persuasive in view of a new ground of rejection(s) and/or objection(s) above.
Citations
6. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. All references are cited for related art. See PTO-892 Form prepared.
Conclusion
7. Claims 1-30 are pending. Claims 1-18 & 30 are rejected. Claims 19-29 are rejected. No claims are allowed.
Contacts
8. Any inquiry concerning this communication or earlier communications from the examiner should be directed to Primary Examiner CAM N. NGUYEN whose telephone number is (571)272-1357. The examiner can normally be reached on M-F (8:30 am – 5:00 pm) at alternative worksite or at cam.nguyen@uspto.gov.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Anthony Zimmer, can be reached at 571-270-3591. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/Cam N. Nguyen/Primary Examiner, Art Unit 1736
/CNN/
April 24, 2026
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