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 .
Response to Amendment
The amendment filed on 06/16/2026 has been entered. Claim(s) 14-22 is/are pending in the application.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 06/16/2026 has been entered.
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.
Claim(s) 14-22 is/are rejected under 35 U.S.C. 103 as being unpatentable over Janikowski et al. ("Super-ferritic stainless steels-the cost-effective answer for heat transfer tubing." NACE CORROSION. NACE, 2008.) in view of Ofei et al. (US20220251032A1)
Regarding Claims 14-16, Janikowski teaches examples of ferritic steel with 26-29% Cr (reading on claims 15-16), and 2.5 or less% Ni (See S44600, S44627, S44660, S44700, S44735, S44800 in Table 1) for use in desalination and water recovery tubing and other heat transfer applications (Abstract); but does not teach that the steel is used in a high-pressure synthesis section for producing urea. However, Ofei teaches a method of urea synthesis with ferritic steel (abstract) where the steel may have 22-35% Cr and 0.5% or less of Ni [0016] (See further examples in Table 1 with good corrosion resistance), as the ferritic steel provides excellent corrosion resistance in high pressure conditions [0032-033]; therefore, one of ordinary skill in the art would have been motivated to use the ferritic steel of Janikowski in a high-pressure synthesis section for the purpose of producing urea.
Regarding Claims 17, the urea synthesis pressure is at least 100 bar [0088] and the temperature is around 200 C [0122]
Regarding Claims 18-19, the prior art is silent regarding the transition temperature of the steel, however, since the prior art steels are substantially identical to the claimed steel, one of ordinary skill in the art would expect the steel transition temperature to be in a similar range to that claimed (and still under the operating temperature) (See MPEP 2112.01(I))
Regarding Claims 20-21, the urea reactor is considered to be a tube sheet of the reactor (See Claim 7)
Regarding Claim 22, there is no added passivation air (or oxygen) [0033]
Response to Arguments
Applicant's arguments filed 06/16/2026 have been fully considered but they are not persuasive.
Regarding Claim 14, Applicant argues the two references are non-analogous art to one another; Janikowski pertains to the field of desalination and water recovery, and operating conditions and corrosiveness of solutions are totally different from urea production technology. The secondary reference, Ofei is an equipment part of a high-pressure synthesis section made of a ferritic steel alloy with a composition useful in providing corrosion resistance to carbamate. Applicant points to differences in the claimed composition of Ofei with exemplary compositions of UNS S44600 and UNS S44660 , summarized in the following table.
PNG
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431
661
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Greyscale
This is not persuasive as Janikowski teaches examples of ferritic steel with 26-29% Cr (reading on claims 15-16), and 2.5 or less% Ni (See S44600, S44627, S44660, S44700, S44735, S44800 in Table 1); the primary reference already teaches the use of UNS S44600 and UNS S44660; the rejection relies on the secondary reference as a teaching showing that ferritic steels of similar composition to that of Janikowski can be used in urea synthesis applications. However, the prior art is relevant for all that it teaches, not just the claimed compositions. Ofei teaches examples where corrosion tests of several grades of ferritic steels may be used compared to conventional examples DSS-01; therefore, the compositional ranges of examples taught by the prior art as a whole clearly overlap with the disclosed ranges of 44660 and 44600. Therefore, one of ordinary skill in the art would have been motivated to use prior art steels of 44600 and 44660 in an application such urea production, as the secondary references teaches steels of similar composition may be used in urea production applications.
Element
FSS-90
FSS-29
DSS-01
UNSS44600
UNSS44660
C
0.002
0.019
0.029
0-0.20
0-0.03
Si
0.20
0.55
0.45
0-1.0
0-1.0
Mn
0.05
0.36
1.25
1.5
0-1.0
P
0.01
0.023
0
0-0.04
0-0.04
S
0.011
0-0.0005
0
0-0.03
0-0.03
Cu
Ni
0.15
0.50
6.20
0.25
1.0-3.5
Cr
26.00
28.53
28.3
23.0-27.0
25.0-28.0
Mo
1
3.63
2.10
3.0-4.0
N
0.01
0.026
0.35
0.17
0-0.04
Nb
0.11
0.35
0
0.1-1.0
Fe
Bal
Bal
Bal
73
60.4-71.0
Conclusion
All claims are identical to or patentably indistinct from, or have unity of invention with claims in the application prior to the entry of the submission under 37 CFR 1.114 (that is, restriction (including a lack of unity of invention) would not be proper) and all claims could have been finally rejected on the grounds and art of record in the next Office action if they had been entered in the application prior to entry under 37 CFR 1.114. Accordingly, THIS ACTION IS MADE FINAL even though it is a first action after the filing of a request for continued examination and the submission under 37 CFR 1.114. See MPEP § 706.07(b). 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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/RICARDO D MORALES/Primary Examiner, Art Unit 1738
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