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
Applicant’s amendment filed 23 January 2026 has been acknowledged. Accordingly, the 35 U.S.C. 112 rejections of claims 28-29, 31, and 37-41 have been withdrawn. Claims 23-44 remain pending in this application and are under full consideration.
Response to Arguments
Applicant's arguments filed 23 January 2026 have been fully considered but they are not persuasive. The respective arguments are addressed below:
Applicant argued that Zardi does not disclose 3 technological features, the technological features in question being: (i) the effluent traversing the recovery heat exchanger first, (ii) the input gas being a makeup gas, and (iii) said at least one integrated recovery heat exchanger and said inter-bed heat exchanger are arranged to be traversed in sequence by the hot process gas effluent from said catalytic bed. In response, Examiner reminds Applicant that one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). In this case, the rejection relied on Humphreys as disclosing these features. Applicant further argues that technological feature (iii) is not disclosed by Humphreys because the claimed recovery heat exchanger is “not arranged in an inter-bed location”. Examiner respectfully disagrees, as the feature of the recovery heat exchanger being arranged in an inter-bed location is not recited in the rejected claim. Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). Applicant further argues that Zardi teaches away from claim 23. This is not persuasive because a reference does not teach away merely because it describes one feature as important, preferred, or even the “main feature of the invention”. A reference teaches away only when it criticizes, discredits, or otherwise discourages the path taken by the claim. The MPEP states that a mere disclosure of alternatives does not amount to teaching away unless the reference actually discourages the claimed solution.
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.
Claims 23-32, 34-37, and 40-44 are rejected under 35 U.S.C. 103 as being unpatentable over Zardi et al. (US-5171543-A), hereinafter “Zardi” in view of Humphreys & Glasgow LTD (GB-2075859-A), hereinafter “Humphreys”.
Regarding Claim 23, Zardi discloses an ammonia converter (converter; see Col. 3 Line 27 and ammonia; see Col. 4 Line 40), comprising:
a plurality of catalytic beds (three catalytic beds (6, 7, and 13); see Col. 3 Line 55) for converting an input gas into an ammonia- containing product gas (gas reacted on the first bed; see Col. 1 Line 43 and ammonia; see Col. 4 Line 40);
wherein:
the plurality of catalytic beds have a cylindrical annular shape delimited by an outer cylindrical wall and an inner cylindrical wall (Fig. 1 shows parts 6, 7, and 13 as being cylinders);
the plurality of catalytic beds are arranged in a pressure vessel (see Fig. 1 and Col. 1 Lines 16-17; “pressure-resistant external shell”) of the ammonia converter sequentially from a first catalytic bed to a last catalytic bed according to a path of the gaseous flow from an inlet to an outlet of the ammonia converter (Fig. 1 shows beds 6, 7, and 13 arranged from top to bottom, and gas runs through bed 6, then 7, then 13; see Col. 3 Lines 31-50), so that for each pair of consecutive beds the effluent gas of an upstream bed of the pair is further processed in the downstream bed of the pair (the gas reacted on the first bed… goes to penetrate the second bed; see (Col. 3 Lines 43-45);
at least one integrated recovery heat exchanger (a first heat exchanger located in the upper end of the shell for recovering heat; see Col. 5 lines 5-6) having a first side arranged to be traversed by reacted process gas effluent from at least one of the catalytic beds (the heat exchanger for said reacted gas; see Col. 3 Lines 65-66) and a second side arranged to be traversed by a heat exchange medium which is not a reactive stream directed to any of the catalytic beds of the ammonia converter (can be a preheater for water; see Col. 3 Lines 66-67); and
a respective inter-bed heat exchanger or a quench system operatively placed between each pair of consecutive catalytic beds of the plurality of catalytic beds contained in the ammonia converter so that, for each pair, the inlet temperature of the downstream bed can be independently controlled (a second heat exchanger connected to the quench gas introducing means and located within the upper most catalyst bed for exchanging heat between the quench gas and hot reacted gas exiting a catalyst bed superimposed between the uppermost catalyst bed and the lowermost catalyst bed; see Col. 5 Lines 9-16);
wherein said at least one integrated recovery heat exchanger and said inter-bed heat exchanger are arranged to be traversed in sequence by the hot process gas effluent from said catalytic bed (“heat exchanger which is situated centrally through the first and second bed”; see Col. 3 Lines 56-58 and “gas reacted on the third bed… is sent… to the upper end… where the heat exchanger for reacted gas is situated”; see Col. 3 Lines 63-66).
Zardi does not explicitly teach the effluent traversing the recovery heat exchanger first. However, Humphreys discloses the effluent of said bed traverses the recovery heat exchanger (RHE) first and then the inter-bed heat exchanger. Specifically, Humphreys discloses two inter-bed heat exchanger sections, both of which can be considered useful in heat recovery due to the fact that the cooling medium is water, so the heat from the effluent heats the water in both heat exchangers to create steam (see Pg. 3 Lines 111-123). The exchangers are disposed so that the effluent traverses the first heat exchanger, or recovery heat exchanger, (in step 6 the gas passes over the first section of the heat exchanger; see Pg. 3 Lines 79-80) and then the second heat exchanger, or the interbed heat exchanger (In step 8 the gas passes over the second section of the heat exchanger in a manner similar to step 6; see Pg. 3 Lines 86-87). Further, Zardi does not explicitly teach the input gas being a makeup gas, but Humphreys does (high pressure make-up gas is fed… contains some inert gases; see Pg. 3 Lines 60-63). Using makeup gas would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention because it would help in controlling the gas temperature rise (see Pg. 1 Lines 44-45).
Zardi and Humphreys are both considered to be analogous to the claimed invention because they are in the same field of multi bed catalytic reactors. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have modified Zardi by incorporating the teachings of Humphreys and disposing the exchangers in a way that forces the effluent to traverse an exchanger for heat recovery prior to the effluent traversing an interbed exchanger. Doing so would generate steam that can be used in steam turbines (see Humphreys Pg. 3 Lines 121-122).
Regarding Claim 24, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Zardi further discloses the integrated recovery heat exchanger contained within a shell (see Col. 5 Lines 5-6), wherein the first side is a region within the shell, and not necessarily within the heat exchange element(s) (the gas reacted on the third bed… is sent… to the upper end of shell, where the heat exchanger for reacted gas is situated; see Col. 3 Lines 62-66). Further, Zardi discloses water entering the exchanger (see Col. 3 Line 67, Fig. 1 Part A) and steam leaving the exchanger (see Col. 3 Line 68, Fig. 1 Part V). Figure 1 of Zardi clearly depicts the recovery heat exchanger as a shell and tube heat exchanger with a plurality of tubes (see Fig. 1, Parts RC, A, and V). The limitations claiming, “a plurality of heat exchange elements and a shell around the plurality of heat exchange elements, said first side is a region around the plurality of heat exchange elements and said second side is an inside of the plurality of heat exchange elements” is a description of a shell-and-tube heat exchanger, which is what Zardi depicts in Figure 1. Additionally, Zardi discloses the recovery heat exchanger being a boiler (see Col. 3 Lines 66-68) and the boiler being a bayonet or hairpins type (see Col. 4 Line 27), which meets the claimed limitation by definition.
Regarding Claim 25, Zardi and Humphreys together discloses the ammonia converter according to claim 24. Zardi further discloses said at least one integrated recovery heat exchanger being a tube heat exchanger (see Fig. 1 Part RC, and “bayonet or hairpins type”; see Col. 4 Line 27) with a bundle of U-tubes (see Fig. 1 Part RC and “hairpins type”; see Col. 4 Line 27) or bayonet tubes (“bayonet type”; see Col. 4 Line 27) connected to a tube sheet (see Fig. 1 Parts RC, A, and V), the tube sheet being on top of the heat exchanger (see Fig. 1 Parts RC, A, V) and the bundle of tubes extending downwards from the tube sheet (see Fig. 1, Part RC).
Regarding Claim 26, Zardi and Humphreys together discloses the ammonia converter according to claim 25. Zardi further discloses said tube sheet of the at least one integrated recovery heat exchanger being located above a top cover of the pressure vessel of the ammonia converter (see Fig. 1, part 1, annotated below).
PNG
media_image1.png
256
399
media_image1.png
Greyscale
Regarding Claim 27, Zardi and Humphreys together discloses the ammonia converter according to claim 23. Zardi further discloses the pressure vessel having a top cover that includes a shell of the at least one integrated recovery heat exchanger (see Fig. 1 annotated above, where the top/end of pressure vessel is a top cover as it is clearly a portion of the shell (part 1)).
Regarding Claim 28, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Humphreys further discloses said at least one integrated recovery heat exchanger being at least partially accommodated in a central cavity of at least one of the catalytic beds (the catalyst in at least one, preferably fixed, bed within the pressure vessel and by making the gas passing through the or each bed flow-by a particular route through an internal, tubular heat exchanger. The heat exchanger is usually divided into sections (with a plurality of catalyst beds, generally one less than the number of beds) by intermediate tube-sheets; see Pg. 2 Line 125 – Pg. 3 Line 2). As explained in the claim 23 rejection, all of the heat exchangers of Humphreys operate both as recovery heat exchangers and inter-bed exchangers. It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have modified Zardi by disposing the recovery heat exchanger at least partially in the cavity of the catalytic beds, as taught by Humphreys, because it would have overcome the limitations of high pressure drop and high unit cost (see Humphreys Pg. 2 Lines 121-125).
Regarding Claim 29, Zardi and Humphreys together disclose the ammonia converter according to claim 28. Zardi further discloses the central cavity of at least one catalytic bed accommodating an inter-bed heat exchanger (a heat exchanger which is situated centrally through the first and second bed; see Col. 3 Lines 56-58) arranged to transfer heat from the hot effluent of the catalytic bed to a reactant gas stream directed to the same or another catalytic bed (gas reacted in the second bed collects in an internal annular zone X2. From here, after exchanging heat with fresh gas in exchanger; see Col. 3 Lines 47-49). Humphreys further discloses the central cavity of at least one catalytic bed accommodating at least a portion of said at least one integrated recovery heat exchanger, as explained in the claim 28 rejection. Please refer to the claim 28 rejection as the rejection for this limitation follows the same rationale.
Regarding Claim 30, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Zardi further discloses the at least one recovery heat exchanger including a recovery heat exchanger which is located above the first catalytic bed of the ammonia converter (see Fig. 1 Parts RC and 6). Humphreys further discloses the recovery heat exchanger being arranged so that the first side of the recovery heat exchanger is traversed by the effluent of said first catalytic bed (In step 5 the gas passes over the first bed of synthesis catalyst… In step 6 the gas passes over the first section of the heat exchanger; see Pg. 3 Lines 74-80). It would have been obvious to a person of ordinary skill in the art to send the effluent from the first catalytic bed through the recovery heat exchanger because it would have cooled the gas (see Humphreys Pg. 3 Lines 80).
Regarding Claim 31, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Humphreys further discloses the at least one integrated recovery heat exchanger including a heat recovery exchanger that is placed downstream the second catalytic bed of the ammonia converter (see Fig. 1 Parts 7 and 8) so that the first side of the at least one integrated recovery heat exchanger is traversed by the effluent of said second catalytic bed (In step 7 the gas passes over the second catalyst bed… In step 8 the gas passes over the second section of the heat exchanger; see Pg. 3 Lines 83-86). It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to arrange the recovery heat exchanger in such a way because it would cool the gas again (see Humphreys Pg. 3 Line 88).
Regarding Claim 32, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Zardi further discloses said heat exchange medium being water or steam (RC can be a pre-heater for water or a boiler for generating steam; see Col. 3 Lines 66-68). While it is understood that the recovery heat exchanger of Zardi would be connected to a steam system, Zardi does not explicitly teach this. However, Humphreys does disclose the recovery heat exchanger being arranged for connection to a steam system (water for the reactor heat exchanger in step 6 and 8 is fed from the steam drum; see Pg. 3 Lines 111-112).
Regarding Claim 34, Zardi and Humphreys together disclose the ammonia converter according to claim 32. Zardi further discloses the at least one integrated recovery heat exchanger including a boiler (RC can be a pre-heater for water or a boiler generating steam; see Col. 3 Lines 66-68).
Regarding Claim 35, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Zardi further discloses wherein said at least one integrated recovery heat exchanger has a shell having a diameter smaller than a diameter of the plurality of catalyst beds (the shell comprises a major cylindrical portion having a constant diameter for containing the catalyst baskets and a minor portion having a diameter smaller than the diameter of the major portion for containing the heat exchanger; see Col. 6 Lines 13-17).
Regarding Claim 36, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Humphreys further discloses said at least one integrated recovery heat exchanger being equipped with a level measurement to monitor a loss of the heat exchange medium inside the pressure vessel. Specifically, Humphreys teaches “Boiler water is fed to the steam drum in step 17 in order to maintain the water level in the steam drum” (see Pg. 3 Lines 118-119). It is understood by those of ordinary skill in the art that this phrase necessitates some sort of level measurement system because it indicates an active response to changes in water level, which cannot occur without a level measurement system. Further, even though the steam drum is separate from the pressure vessel, a level measurement system for the steam drum would also reflect losses inside the heat exchanger, and therefore inside the pressure vessel, because the steam drum and heat exchanger are hydraulically and thermodynamically connected, as they function as a single, closed-volume loop in terms of water/steam mass balance as exemplified in Figure 1 of Humphreys (part 16) and by the teaching that the “Water for the reactor heat exchanger in step 6 and 8 is fed from the steam drum in step 16 where steam is separated from the water. The water flows through the tubes of the heat exchanger in steps 6 and 8 by natural circulation. In this embodiment, the water flows downwards and the mixture of water and steam flow upwards” (see Pg. 3 Lines 111-117). It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to use a level measurement system in order to maintain the water level (see Humphreys Pg. 3 Line 119).
Regarding Claim 37, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Zardi further discloses the pressure of the heat exchange medium in the second side of said at least one integrated recovery heat exchanger being lower than the pressure of the reactant process stream (“a reactor according to this invention… at a pressure of 140 bar abs”; see Col. 4 Lines 34-35 and “steam at 110 ata”; see Col. 4 Line 40). Further, this limitation refers only to a pressure differential, which is a result of system operation, not a structural difference in the apparatus. The Courts have held that apparatus claims must be structurally distinguishable from the prior art in terms of structure, not function. See In re Danley, 120 USPQ 528, 531 (CCPA 1959); and Hewlett-Packard Co. V. Bausch and Lomb, Inc., 15 USPQ2d 1525, 1528 (Fed. Cir. 1990) (see MPEP §§ 2114 and 2173.05(g)).
Regarding Claim 40, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Zardi further discloses the interbed heat exchanger, which is operated with an external fluid, located between two consecutive catalytic beds (a heat exchanger which is situated centrally through the first and second bed and is fed with fresh gas; see Col. 3 Lines 56-58); a heat exchanger or a quench system (quench gas introducing means; see Col. 6 Lines 4-5) that is separate from said heat exchanger operated with an external fluid (the annular central zone being in fluid communication with the quench gas introducing means; see Col. 6 Lines 8-10), and is arranged to adjust the temperature (quenching does this by definition) of the process stream entering the downstream bed of said two consecutive catalytic beds (the gas reacted on the first bed collects in the annular central zone and from here goes to penetrate the second bed; see Col. 3 Lines 43-45).
Regarding Claim 41, Zardi and Humphreys together disclose the ammonia converter according to claim 23. Zardi further discloses the interbed heat exchanger, which is operated with an external fluid, located between two consecutive catalytic beds (a heat exchanger which is situated centrally through the first and second bed and is fed with fresh gas; see Col. 3 Lines 56-58); at least another heat exchanger (alternatively, two exchangers; see Col. 4 Line 26), which is a gas pre-heater, arranged to transfer heat from a reacted gas withdrawn from at least one catalytic bed to a stream of a fresh reactive gas (The gas reacted on the second bed collects in internal annular zone X2. From here, after exchanging heat with fresh gas in exchanger; see Col. 3 Lines 47-49; it is understood that the fresh gas is being heated, making this a pre-heater, because the reacted gas is referred to as “hot reacted gas”; see Col. 5 Line 13), the ammonia converter being internally arranged so that an input of fresh gas is passed over the internal surface of the pressure vessel of the ammonia converter before admission thereof to said gas pre-heater, so that the pressure vessel is cooled by the fresh gas (fresh gas entering from the bottom of the reactor an running though from bottom to top of the airspace between the shell internal wall and the cartridge external wall, for the purpose of reducing to a minimum temperature of the shell; see Col. 3 Lines 31-35).
Regarding Claim 42, Humphreys discloses a plant (each reactor for this plant; see Pg. 5 Line 8) for the synthesis of ammonia (formation of ammonia; see Pg. 2 Lines 106-107), the plant comprising: the ammonia converter according to claim 23 (disclosed by Zardi and Humphreys as explained in the claim 23 rejection); and a steam system (steam drum in step 16 where steam is separated from the water; see Pg. 3 Lines 112-113); wherein an input and an output of the second side of the at least one integrated recovery heat exchanger integrated in the ammonia converter are connected to the steam system (Water for the reactor heat exchanger in step 6 and 8 is fed from the steam drum… water flows downwards and the mixture of water and steam flow upwards; see Pg. 3 Lines 111-112 and Fig. 1 Part 16). Using a steam system with the reactor would have been obvious to a person of ordinary skill in the art before the effective fling date of the claimed invention because it would enable steam to be used in steam turbines, steam heaters, as process steam, etc. (see Humphreys Pg. 3 Lines 121-123).
Regarding Claim 43, Zardi discloses a process of synthesis of ammonia (“a process for exothermic heterogeneous synthesis”; see Col. 1 Lines 7-8 and “can be achieved of 634,000Kcal/MT of ammonia”; see Col. 4 Line 39), the process comprising: passing a gas through a plurality of annular (annular; see Col. 3 Line 44) catalytic beds (gas flows over a series of catalytic beds; see Col. 1 Lines 8-9) arranged inside a pressure vessel of an ammonia converter (consisting of a pressure-resistant external shell; see Col. 1 Lines 16-17 and Fig. 1 Parts 1, 6, 7, and 13), including at least a first bed and a second bed (first bed; see Col. 3 Line 43 and second bed; see Col. 3 Line 45), wherein said plurality of annular catalytic beds are arranged sequentially so that a partially reacted gas effluent from the first bed is further reacted in the second bed (The gas reacted on the first bed… and from here goes to penetrate the second bed… the gas reacted on the second bed; see Col. 3 Lines 43-47); transferring heat from the effluent of at least one of said catalytic beds to a heat exchange medium (The gas reacted on the second bed… From here, after exchanging heat with fresh gas; see Col. 3 Lines 47-49).
Zardi does not explicitly disclose this heat transfer happening in a recovery heat exchanger or the medium being a non-reactive stream. However, Humphreys discloses said transfer of heat being performed in a recovery heat exchanger which is integrated in the ammonia converter according to claim 23 (please refer to the rejection of claim 23 as the rejection of this limitation follows the same rationale); said heat exchange medium is not a reactive stream of the ammonia synthesis process (water for the reactor heat exchanger in step 6; see Pg. 3 Line 111). It would have been obvious to a person of ordinary skill in the art to use a recovery heat exchanger in this way, and to use a non-reactive stream as the heat medium (steam) because doing so would generate steam that can be used in steam turbines (see Humphreys Pg. 3 Lines 121-122).
Further, Zardi does not explicitly disclose the feed gas being a make-up gas containing hydrogen and nitrogen. However, Humphreys does disclose using a make-up gas (see Pg. 3 Lines 60-63) containing nitrogen and hydrogen (see Pg. 3 Lines 60-64 and “formation of ammonia from hydrogen and nitrogen”; see Pg. 2 Lines 106-107). This composition would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention because it would have enabled ammonia formation (see Humphreys Pg. 2 Lines 106-107) and would help control the gas temperature rise (see Pg. 1 Lines 44-45).
Regarding Claim 44, Zardi and Humphreys together disclose the process according to claim 43. Zardi further discloses the heat exchange medium being water or steam (RC can be a pre-heater for water or a boiler generating steam; see Col. 3 Lines 66-68) and the process includes the production of steam (generating steam; see Col. 3 Lines 68) in said at least one integrated recovery heat exchanger (RC can be a boiler generating steam (see Col. 3 Lines 66-68). Humphreys also discloses said heat exchange medium being water or steam (water for the reactor heat exchanger in step 6; see Pg. 3 Line 111) and the process includes the production of steam (“water and steam flow upwards”; see Pg. 3 Lines 116-117 and “steam leaves the steam drum”; see Pg. 3 Line 120) or of superheated steam (steam, which is then superheated; see Pg. 5 Line 11) in said at least one integrated recovery heat exchanger (water and steam flow upwards; see Pg. 3 Lines 116-117 and Fig. 1 Part 16). It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have used this steam system taught by Humphreys because this steam could be used in steam turbines, steam heaters, as process steam, etc. (see Humphreys Pg. 3 Lines 121-123).
Claim 33 is rejected under 35 U.S.C. 103 as being unpatentable over Zardi et al. (US-5171543-A), hereinafter “Zardi” in view of Humphreys & Glasgow LTD (GB-2075859-A), hereinafter “Humphreys” and further in view of Steammain.com (Superheated steam introduction).
Regarding Claim 33, Zardi and Humphreys together disclose the ammonia converter according to claim 32. Humphreys further discloses said at least one integrated recovery heat exchanger including a steam superheater (steam, 56, which is then superheated in a heater; see Pg. 5 Line 11). It would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have included a steam superheater because it is well known in the art that superheated steam is more thermodynamically efficient than saturated steam, as taught by Steammain.com (see Paragraph 2, Uses for superheated steam?).
Claim 38 is rejected under 35 U.S.C. 103 as being unpatentable over Zardi et al. (US-5171543-A), hereinafter “Zardi” in view of Humphreys & Glasgow LTD (GB-2075859-A), hereinafter “Humphreys” and Czuppon (EP-0994072-B1).
Regarding Claim 38, Zardi and Humphreys together disclose the ammonia converter according to claim 23.
Modified Zardi does not explicitly teach the pressure of the heat exchange medium in the second side of said at least one integrated recovery heat exchanger being higher than the pressure of the reactant process stream. However, Czuppon discloses a shell and tube reactor (see [0010]) in which the pressure of the side containing the heat exchange medium (water) is from 60 to 150 bar (see [0010]) and the pressure of the side containing the reactant process stream (synthesis loop purge gas to the inlet of the tubes; see [0011]) is 60 to 210 bar (see [0013]) indicating that the heat exchange medium can be at a higher pressure than the reactant process stream.
Zardi and Czuppon are both considered to be analogous to the claimed invention because they are in the same field of ammonia synthesis reactors. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have used a heat exchange medium at higher pressure than the process gas. Doing so minimizes the temperature difference between the tube and shell sides (see [0024]).
Claim 39 is rejected under 35 U.S.C. 103 as being unpatentable over Zardi et al. (US-5171543-A), hereinafter “Zardi” in view of Humphreys & Glasgow LTD (GB-2075859-A), hereinafter “Humphreys” and Malmali et al. (US-20170152149-A1), hereinafter “Malmali”.
Regarding Claim 39, Zardi and Humphreys together disclose the ammonia converter according to claim 23.
Modified Zardi does not explicitly teach a control system. However, Malmali discloses a control system (reactor control system; see Abstract) that is configured to operate a shutdown of the ammonia converter according to a shutdown procedure (by shutting off the recirculation pump 44. The shutdown of one or both of the reactant gases through the gas feeds; see [0089]), wherein the shutdown procedure involves pressure control (“by shutting off the recirculation pump”; see [0089] and “control system controls one or both of a temperature and pressure”; see Abstract).
Regarding the limitation claiming “wherein in the shutdown procedure a pressure of the heat exchange medium traversing the at least one integrated recovery heat exchanger is maintained below a pressure of the reactant gas in the ammonia converter”, the limitation of the heat exchange medium being at a lower pressure than the reactant gas is disclosed by Zardi, as explained in the claim 37 rejection. It is well known and understood by those of ordinary skill in the art that the fluid in the low-pressure side of an exchanger should remain at a lower pressure than the fluid in the high-pressure side. This is due to safety and mechanical integrity based on principals of thermodynamics and fluid dynamics. In this case, the intended low-pressure side is the heat exchange medium, and the high-pressure side is the process gas. If the low-pressure side fails and there is a leak or rupture, fluid moves from high pressure to low pressure according to Navier-Stokes and Bernoulli principal. So, if the heat exchange medium rises above the pressure of the process gas, this would result in the heat exchange medium flowing into the high-pressure side, which in the case of Zardi and Humphreys, is the shell side. This would result in water (the heat exchange medium as disclosed by Zardi (see Col. 3 Line 67) and Humphreys (see Pg. 3 Line 111)) entering the process gas loop, which would result in unintentional mixing, and very likely destroying catalyst and causing corrosion. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to always maintain the fluid in the low-pressure side of the exchanger at a lower pressure than that of the high-pressure side.
Zardi and Malmali are both considered to be analogous to the claimed invention because they are in the same field of ammonia synthesis. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have modified Zardi by incorporating the teachings of Malmali and including a control system and shutdown procedure. Doing so would enable temporary ceasing of ammonia production (see Malmali [0089]).
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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALYSSA LEE KUYKENDALL whose telephone number is (571)270-3806. The examiner can normally be reached Monday- Friday 9:00am-5:00pm.
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, Claire Wang can be reached at 571-270-1051. 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.
/A.L.K./Examiner, Art Unit 1774
/CLAIRE X WANG/Supervisory Patent Examiner, Art Unit 1774