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
Claims 1-10 and 12-15 of L. Porro et al., US 18/682,550 (May 30, 2022) are pending. Claims 12-15, to non-elected invention of Group (II) are withdrawn from consideration pursuant to 37 CFR 1.142(b). Claims 1-10 are under examination on the merits and are rejected.
Election/Restrictions
Applicant elected Group (I), claims 1-10, without traverse in the Reply to Restriction Requirement filed on August 10, 2026. Claims 12-15, to non-elected invention of Group (II) are withdrawn from consideration pursuant to 37 CFR 1.142(b). The restriction is made FINAL.
Rejections 35 U.S.C. 112(b)
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION. — The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
Pursuant to 35 U.S.C. 112(b), the claim must apprise one of ordinary skill in the art of its scope so as to provide clear warning to others as to what constitutes infringement. MPEP 2173.02(II); Solomon v. Kimberly-Clark Corp., 216 F.3d 1372, 1379, 55 USPQ2d 1279, 1283 (Fed. Cir. 2000). A claim is indefinite when it contains words or phrases whose meaning is unclear. MPEP § 2173.05(e) (citing In re Packard, 751 F.3d 1307, 1314, 110 USPQ2d 1785, 1789 (Fed. Cir. 2014)).
Unclear Claim Language
Claim 8 is rejected under 35 U.S.C. 112(b) as being indefinite because certain parameters required (e.g., time) to calculate whether claim 8 is met are not defined. Claim 8 recites:
8. (Currently Amended) The method according to claim 1, wherein an amount of nitrogen comprised in the SNCR/SCR solution represents from 0.5 to 10 % of the amount of nitrogen, introduced as ammonia, in a urea-producing plant.
First note that the specification and the art teach that the claim 1 reaction occurs in two steps, where the second step of ammonium carbamate (NH2C(O)ONH4) conversion to urea is an equilibrium1:
2NH3 + CO2 [Symbol font/0xAE] NH2C(O)ONH4 [Symbol font/0xAB] (NH2)2CO + H2O + NH2C(O)ONH4
Specification at page 3, lines 30-35; J. Meessen, 86 Chemie Ingenieur Technik, 2180-2189 (2014) (“Meessen”) (see page 2181); J. Meessen, 37 Ulmann’s Encyclopedia of Industrial Chemistry, 657-695 (2012). The specification teaches that the gist of claim 1 is that the operator can either: (1) per the prior art, recycle the ammonium carbamate fraction (which may comprise other ammonium salts)2 back to the urea synthesis or simply discard it; or (2) per claim 1 step c), dilute the separated ammonium carbamate fraction so as to form a SNCR/SCR solution. Specification at page 4, lines 24-35. The specification and art teach that a problem with recycling the ammonium carbamate/water fraction back to the urea reactor is that the water adversely affects the urea-forming equilibrium. Specification at page 4, lines 25-27; Meessen at page 2184, col. 1.
With this background in mind, the claim 8 “amount of nitrogen, introduced as ammonia, in a urea-producing plant” is interpreted in view of the specification. The specification teaches:
In one embodiment, the amount of nitrogen comprised in the SNCR/SCR solution obtained in step c) represents from 0.5% to 10%, from 0.5% to 8%, from 0.% to 6%, or from 0.5% to 4.0% of the amount of nitrogen introduced, as ammonia, in a urea-producing plant.
The amount of nitrogen comprised in the aqueous composition obtained in step c) may represent an amount of the total nitrogen introduced in the plant that varies over time, as this may depend on factors external to the plant, such as demand in urea-based products and demand in solution for SNCR/SCR.
Specification at page 7, lines 9-14 (emphasis added). Thus, the specification teaches that the amount of introduced nitrogen referenced is that employed that “varies over time”. And the claim 8 practitioner decides (based on demand) whether to: (1) recycle the ammonium carbamate fraction back to the urea reactor or simply discard it, or (2) per claim 1 step c, dilute the ammonium carbamate fraction (per the invention of claim 1) to form the claimed SNCR/SCR solution. Specification at page 7, lines 9-14.
Clam 8 is indefinite because “the amount of nitrogen, introduced as ammonia, in a urea-producing plant” is not defined by a particular time of operation. It is unclear whether one of skill calculates the introduced amount of ammonia, for example, from the plant’s inception or over some other time period, for example, a month in which there was a demand for SNCR/SCR solution and the plant operator decided not to recycle the ammonium carbamate fraction back to urea synthesis.
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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under AIA 35 U.S.C. 103(a) 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.
Claims 1-10 are rejected under AIA 35 U.S.C. 103 as being unpatentable over primary references J. Meessen, 86 Chemie Ingenieur Technik, 2180-2189 (2014) (“Meessen”) and/or J. Mennen, US 10,633,331 (2020) (“Mennen”) in view of J. Hofmann et al., US 4,997,631 (1991) (“Hofmann”) and J. Hofmann, WO 96/06674 (1996) (“Hofmann-2”).
J. Meessen, 86 Chemie Ingenieur Technik, 2180-2189 (2014) (“Meessen”)
Meessen teaches that the reaction of carbon dioxide with ammonia may be split into two parts. Meessen at page 2180. In (1) a first fast, exothermic step, ammonium carbamate is formed from ammonia and carbon dioxide, which reaction will run essentially to completion; (2) in a second, slow, endothermic equilibrium reaction, ammonium carbamate dehydrates to form urea and water, the yield of urea being limited by the underlying reaction thermodynamics; the reaction only runs in the liquid phase, and there is no known catalyst to speed it up.
(step 1) 2NH3 + CO2 [Symbol font/0xAE] NH2C(O)ONH4 (Reaction 2)
(step 2) NH2C(O)ONH4 [Symbol font/0xAB] (NH2)2CO + H2O (Reaction 3)
Meessen at page 2180.
Meessen teaches that ammonium carbamate can also hydrate to form ammonium carbonate (NH4)2CO3, which in turn may split off ammonia to form ammonium bicarbonate (NH4)HCO3. Meessen at page 2181, col. 1. So, upon mixing the pure components NH3, CO2 and H2O, a mixture is obtained that contains all of the abovementioned species, including the ionic forms of the salts involved, where the exact composition of such a mixture will depend on the initial amounts of NH3, CO2 and H2O, on temperature and, to some extent, on residence time. Meessen at page 2181, col. 1.
Meessen teaches that since the urea yield per pass is limited, the only way it is possible to achieve full conversion of the feed materials (ammonia and carbon dioxide) to urea is to recycle unconverted material. Meessen at page 2183, col. 1.
Meessen teaches that in conventional stripping processes, the initial urea solution (comprising an equilibrium mixture of desired urea and by-product ammonium carbamate, NH3 and CO2) is treated by adjustment of temperature and/or pressure to decompose the ammonium carbamate back to ammonia and carbon dioxide; and upon distillation a top product of pure ammonia and a bottom product of ammonium carbamate/water. Meessen at page 2183, col. 2. The condensed ammonia and bottom aqueous solution of ammonium carbamate in water, are recycled to the synthesis reactor via high-pressure (HP) carbamate pumps. Meessen at page 2183, col. 2 to 2184, col. 1.
Meessen thus teaches claim 1 steps a) and b):
Claim 1 . . . a) reacting ammonia and carbon dioxide in a reactor, thereby obtaining an aqueous composition comprising urea and ammonium salts;
b) processing the aqueous composition obtained in step a), thereby obtaining
a first aqueous solution comprising urea, and
a second aqueous solution comprising ammonium salts . . .
Meessen teaches that the recycled ammonium carbamate is unavoidably associated with the recycle of water to the synthesis section, and the water in the reactor has a very detrimental effect on the achievable urea yield per pass because reaction step 2 is an equilibrium. Meessen at page 2184, col. 1.
Meessen teaches that various improvements to the stripping/recycling were subsequently developed. Meessen at page 2184 et seq. In a first development, the mixture of urea, water, and unconverted material (ammonium carbamate, surplus ammonia and carbon dioxide), called urea synthesis solution, is led to the stripping stage, where ammonium carbamate is decomposed by medium pressure steam and transformed into a gaseous (supercritical) phase (i.e., ammonia and carbon dioxide). Meessen at page 2184, col. 2. The ammonia and carbon dioxide (off-gases) from the stripping stage are then led to a carbamate condensation stage, to reform the ammonium carbamate (now separated from the urea solution). Meessen at page 2184, col. 2. The separated ammonium carbamate (now with low water content) can be recycled for urea synthesis according to Reaction (3).
J. Mennen, US 10,633,331 (2020) (“Mennen”)
Mennen teaches production of solid urea suitable. Mennen at col. 1, lines 15-23. Mennen teaches improvement on in prior art processes, where, in the process of the invention, the urea-comprising aqueous stream obtained as described above, is subjected to flash crystallization. Therein the solution is subjected to flashing so as to obtain a solid crystallized urea containing product and an ammonia and water containing vapor. Mennen at col. 6, lines 15-20.
In the portion relevant to the § 103 rejection and aimilar to Meessen, Mennen teaches that urea is generally produced by introducing an ammonia excess together with carbon dioxide at a pressure between 12 and 40 MPa and at a temperature between 150° C. and 250° C into a urea synthesis zone according to two consecutive reaction steps. Mennen at col. 4 lines 27-41. Mennen teaches that the urea synthesis solution substantially consists of urea, water, unbound ammonia and ammonium carbamate, where the ammonium carbamate and the ammonia are removed from the solution and are generally returned to the urea synthesis zone. Mennen at col. 4, lines 44-48.
Mennen teaches separation of a urea solution and an ammonium carbamate solution as follows:
Mennen teaches that a recovery section usually comprises a heater, a liquid/gas separation section and a condenser. The urea solution entering a recovery section is heated to vaporize the volatile components ammonia and carbon dioxide from that solution. The heating agent used in the heater is usually steam. The formed vapor in said heater is separated from the aqueous urea solution in the liquid/gas after which said vapor is condensed in the condenser to form a carbamate solution. The released condensation heat is usually dissipated in cooling water. The formed carbamate solution in that recovery section operated at a lower pressure than the pressure in the synthesis section is preferably returned to the urea synthesis section operating at synthesis pressure.
Mennen at col. 5, lines 19-32.
Mennen thus teaches claim 1 steps a) and b):
Claim 1 . . . a) reacting ammonia and carbon dioxide in a reactor, thereby obtaining an aqueous composition comprising urea and ammonium salts;
b) processing the aqueous composition obtained in step a), thereby obtaining
a first aqueous solution comprising urea, and
a second aqueous solution comprising ammonium salts . . .
Difference between Meessen and Mennen from Claim 1
Neither of primary references Meessen or Mennen teach the claim 1 step of:
c) diluting the second aqueous solution comprising ammonium salts obtained in step b) with a third aqueous solution, thereby producing the SNCR/SCR solution.
That is, while Meessen/Mennen teach obtaining the second aqueous exactly as per claim 1, step a) and step b), they do not teach diluting this stream.
J. Hofmann et al., US 4,997,631 (1991) (“Hofmann”)
Hofmann teaches a process for reducing nitrogen oxides in the effluent from the combustion of a carbonaceous fuel without generating a substantial amount of nitrous oxide comprises introducing into the effluent from the combustion of a carbonaceous fuel a treatment agent comprising ammonium carbamate. Hofmann at col. 2, lines 35-50. Hofmann teaches that nitrogen oxides are troublesome pollutants in the combustion streams of boilers and comprise a major irritant in smog. Hofmann at col. 1, lines 29-31. Hofmann teaches that selective non-catalytic reduction (SNCR) processes, which are temperature dependent, generally utilize a nitrogenous substance such as urea or ammonia. Hofmann at col. 1, lines 52-54.
Hofmann teaches that preferably, the treatment agent (i.e., ammonium carbamate) is injected into the effluent as an aqueous solution in the range from saturated to dilute. Hofmann at col. 4, lines 38-43.
Hofmann teaches that the level of ammonium carbamate present in the solution is in the range of about 0.5% to about 50% by weight, preferably about 5% to about 30% by weight. Hofmann at col. 4, lines 48-51.
J. Hofmann, WO 96/06674 (1996) (“Hofmann-2”)
Hofmann-2 teaches a process for the catalytic reduction of nitrogen oxides in a combustion 5 effluent comprising: (a) directing the effluent through a passage including a catalysis zone containing a catalyst effective for reducing NOx in the presence of ammonia and oxygen; (b) introducing into the passage, an aqueous solution of a NOx-reducing agent consisting essentially of ammonium carbamate. Hofmann-2 at page 5, lines 4-10.
Hofman-2 teaches that, in the preferred embodiment, the carbamate is produced in equipment conventional for urea synthesis, but under conditions effective to maximize the production of ammonium carbamate and minimize the production of urea. Hofmann-2 at page 5, lines 19-23. Hofmann-2 teaches that preferably, the combined amount of urea and other nitrogenous species such as ammonium carbonate, ammonium bicarbonate, and the double salt of ammonium carbonate (often called commercial ammonium carbonate, NH4HCO2-NH2COONH4), is maintained at a level of less than about 10%, more preferably, less than 6%, and most preferably less than 2%. Hofmann-2 at page 5, lines 23-27. Hofmann-2 teaches that also, preferably, the carbamate is recovered from the process in the form of a solid. Hofmann-2 at page 6, lines 1-2.
Hofmann-2 teaches that in the preferred process, the carbamate is produced by combining liquid ammonia and liquid carbon dioxide at a pressure preferably above the critical pressure of ammonia, e.g., of from about 120 to about 200 atmospheres at a temperature of from about 135° to about 200°C, and then recovering the ammonium carbamate. Hofmann-2 at page 8, lines 3-7.
Hofmann-2 teaches that a solution of ammonium carbamate (aqueous solution) is introduced into the effluent at an effluent temperature wherein the ammonium carbamate readily converts to ammonia in order to facilitate the catalytic reduction of nitrogen oxides. Hofmann-2 at page 9, lines 1-3.
Obviousness Rationale
Claim 1 is obvious because one of ordinary skill is motivated to manufacture urea by reacting ammonia with carbon dioxide as taught by Meessen and/or Mennen to give a reaction product comprising the equilibrium ratio of urea and ammonium carbamate. Meessen at page 2180. One of ordinary skill thereby meets the claim 1 limitation of:
Claim 1 . . . a) reacting ammonia and carbon dioxide in a reactor, thereby obtaining an aqueous composition comprising urea and ammonium salts . . .
One of ordinary skill is further motivated to employ the conventional stripping process of Meessen and/or Mennen to separate the ammonium carbamate from the urea to give, per claim 1, a first aqueous solution comprising urea, and a second aqueous solution comprising ammonium salts. In this regard, Meessen teaches that in conventional stripping processes, the initial urea solution (comprising an equilibrium mixture of desired urea and by-product ammonium carbamate, NH3 and CO2) is treated by adjustment of temperature and/or pressure to decompose the ammonium carbamate back to ammonia and carbon dioxide; and upon distillation a top product of pure ammonia and a bottom product of ammonium carbamate/water. Meessen at page 2183, col. 2.
One of ordinary skill thereby meets the claim 1 limitations of:
Claim 1 . . . b) processing the aqueous composition obtained in step a), thereby obtaining
a first aqueous solution comprising urea, and
a second aqueous solution comprising ammonium salts . . .
Claim 1 step c) is obvious because rather than following the Meessen/Mennen teaching wherein condensed ammonia and bottom aqueous solution of ammonium carbamate in water, are recycled to the synthesis reactor via high-pressure (HP) carbamate pumps (Meessen at page 2183, col. 2 to 2184, col. 1) ,one of ordinary skill is motivated by Hoffman and/or Hoffman-2 to employ the separated aqueous solution of ammonium carbamate in water as a selective non-catalytic reduction (SNCR) solution to remove NOx species from the effluent from the combustion of a carbonaceous fuel. Hofmann at col. 2, lines 35-50. One of ordinary skill is so motivated because this aqueous ammonium carbamate stream represents a suitable source of ammonium carbamate. Further, while Meessen/Mennen teach that this aqueous ammonium carbamate stream can be recycled back to urea synthesis; however, Meessen also teaches that the recycled ammonium carbamate is unavoidably associated with the recycle water to the synthesis section, and the water in the urea reactor has a very detrimental effect on the achievable urea yield per pass because reaction step 2 is an equilibrium. Meessen at page 2184, col. 1. Thus, rather than Meessen’s possible recycle, the aqueous ammonium carbamate stream can be put to use as a selective non-catalytic reduction (SNCR) solution as taught by Hofmann and/or Hofmann-2.
One of ordinary skill is motivated to further dilute the Meessen/Mennen aqueous ammonium carbamate stream with water for use in Hofmann’s non-catalytic reduction (SNCR) process to the appropriate level, where Hofman teaches the treatment agent (i.e., ammonium carbamate) is injected into the effluent as an aqueous solution in the range from saturated to dilute (Hofmann at col. 4, lines 38-43) and that the level of ammonium carbamate present in the solution is in the range of about 0.5% to about 50% by weight, preferably about 5% to about 30% by weight. Hofmann at col. 4, lines 48-51. One of ordinary skill thereby meets the following limitation of claim 1.
Claim 1 . . . c) diluting the second aqueous solution comprising ammonium salts obtained in step b) with a third aqueous solution, thereby producing the SNCR/SCR solution.
Every limitation of claim 1 is met by the combination of Meessen and Hofmann and claim 1 is therefore obvious in view of this reference combination.
Claim 2 recites:
2. The method according to claim 1, wherein the aqueous composition obtained in step c) comprises from 10 to 40 weight% of nitrogen, expressed as ammonia.
The claim 1, step c) composition, as proposed above, comprises primarily ammonium salts, and possible some free ammonia. Specification at page 4, lines 4-7. The specification teaches that the three possible salts are ammonium bicarbonate (NH4H(O3), ammonium carbonate ((NH4)2(O3), and ammonium carbamate (NH2CO3NH4). Specification at page 4, lines 3-4. Consistent with the specification, the claim 2 weight percent is interpreted as calculated by determining the total weight of NH3 (as an additive weight from any of NH3, NH2, and NH4 species) and dividing this by the total weight of the solution Specification at page 5, lines 10-23.3 For example, 10 g of ammonium carbamate (NH2CO3NH4, 78.071 g/mol) in 90 g of water has 4.36 grams of NH3 for a “weight% of nitrogen, expressed as ammonia” of 4.36g/100g [Symbol font/0xB4] 100% = 4.36 wt%. Hofmann teaches that the level of ammonium carbamate present in the solution is in the range of about 0.5% to about 50% by weight, preferably about 5% to about 30% by weight. Hofmann at col. 4, lines 48-51. Hofmann’s weight% ranges expressed as ammonium carbamate convert to the following ranges of nitrogen, expressed as ammonia 0.21% to about 21% by weight, preferably about 2.1% to about 13% by weight. Hofmann’s weight% ranges of ammonium carbamate, expressed as ammonia, therefore overlap with the claim 2 ranges and prima facie case of obviousness is established. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP § 2144.05(I).
Respecting clam 3, Hofmann’s weight% ranges expressed as ammonium carbamate (NH2CO3NH4, 78.071 g/mol) convert to the following ranges of carbon, expressed as carbon dioxide (CO2, 44.01 g/mol) 0.28% to about 28% by weight, preferably about 2.8% to about 17% by weight. Hofmann’s weight% ranges of ammonium carbamate, calculated for carbon, expressed as carbon dioxide, therefore overlap with the claim 3 ranges and prima facie case of obviousness is established. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists. MPEP § 2144.05(I).
Respecting claim 4, Hofmann’s aqueous composition of ammonium carbamate is essentially the same composition in claim 1, step c), produced according to the same method and will exhibit the claimed functional characteristics. In any case, ammonium carbonate is “is extremely soluble in water”. Chemical Book, Uses and Reactions of Ammonium Carbamate (2024). Therefore, Hofmann’s aqueous composition of ammonium carbamate meets the claim 4 functional language of “does not form crystals above 15 °C”.
Respecting claim 5, Hofmann’s aqueous composition of ammonium carbamate is essentially the same composition in claim 1, step c), produced according to the same method and will exhibit the claimed functional characteristics. In any case, Hofmann’s aqueous composition of ammonium carbamate will have a boiling point of at least 35 °C since it is an aqueous composition with no ammonia, where water boils at 100 °C. See specification at page 6, lines 12-16.
Claim 6 recites:
6. The method according to claim 1, wherein step b) comprises
generating the first aqueous solution comprising urea and a gaseous stream comprising water, ammonia, and carbon dioxide, from the aqueous composition comprising urea and ammonium salts obtained in step a), and
condensing the gaseous stream comprising water, ammonia, and carbon dioxide into the second aqueous solution comprising ammonium salts.
These additional limitations are clearly met by primary references Meessen/Mennen, which teaches these steps exactly. That is, Meessen teaches that in conventional stripping processes, the initial urea solution (comprising an equilibrium mixture of desired urea and by-product ammonium carbamate, NH3 and CO2) is treated by adjustment of temperature and/or pressure to decompose the ammonium carbamate back to ammonia and carbon dioxide; and upon distillation a top product of pure ammonia and a bottom product of ammonium carbamate/water is obtained. Meessen at page 2183, col. 2.
Claim 7 recites:
7. The method according to claim 6, wherein
generating the first aqueous solution comprising urea and a gaseous stream comprising water, ammonia, and carbon dioxide, from the aqueous composition comprising urea and ammonium salts obtained in step a), is achieved by heating up the aqueous composition comprising urea and ammonium salts.
Again, Meessen/Mennen teaches these exact steps. That is, Meessen teaches the initial urea solution (comprising an equilibrium mixture of desired urea and by-product ammonium carbamate, NH3 and CO2) is treated by adjustment of temperature and/or pressure to decompose the ammonium carbamate back to ammonia and carbon dioxide. Meessen at page 2183, col. 2.
Claim 8 recites:
8. (Currently Amended) The method according to claim 1, wherein an amount of nitrogen comprised in the SNCR/SCR solution represents from 0.5 to 10 % of the amount of nitrogen, introduced as ammonia, in a urea-producing plant.
Claim 8 was discussed and interpreted above in the § 112(b) rejection. Here, the claimed amount of “nitrogen comprised in the SNCR/SCR solution” must be “0.5 to 10 % of the amount of nitrogen, introduced as ammonia, in a urea-producing plant”. As discussed above, to calculate this value, one of ordinary skill must know the amount of nitrogen introduced as a reactant in a urea producing plant over an undefined time period.
As discussed above in the § 112(b) rejection, the specification teaches that the amount of introduced nitrogen referenced is that employed that “varies over time”. And the claim 8 practitioner decides (based on demand) whether to: (1) recycle the ammonium carbamate fraction back to the urea reactor or simply discard it, or (2) per claim 1 step c), dilute the ammonium carbamate fraction (per the invention of claim 1) to form the claimed SNCR/SCR solution. Specification at page 7, lines 9-14.
Claim 8 is obvious because, based on demand, where the plant is commissioned to provide an ammonium carbamate fraction (for SNCR/SCR use) as well as urea, one of ordinary skill is motivated by Meessen in view of Hofmann to convert that portion of the ammonium carbamate fraction to SNCR/SCR solution (per claim 1, step c)) by dilution with a third aqueous solution that is commensurate with the demand for the SNCR/SCR solution. The claim 8 recitations do not provide a patentable distinction from the cited art because, per the specification, the “amount of nitrogen comprised in the SNCR/SCR solution” is simply a function of the arbitrary demand, at a particular time, for the SNCR/SCR solution.
Claim 9 is obvious for the following reasons. Claim 9 recites:
9. The method according to claim 1, wherein the aqueous composition obtained in step c) comprises from 0.01 to 5.0 weight% of urea.
Meessen does not state, per claim 9, that bottom aqueous solution of ammonium carbamate in water has a percentage of urea. However, per the rationale below, practice of the cited art as proposed inherently results in the claim 9 limitation of “comprises from 0.01 to 5.0 weight% of urea”. MPEP § 2112(V).
In this regard, the specification teaches that Figure 1 is a schematic representation of a urea-producing plant based on the Stamicarbon technology. Specification at page 10, lines 28-29. The specification teaches that the low-pressure section 2 also generates an aqueous solution comprising ammonium salts, that is re-injected in the synthesis section. Specification at page 11, lines 2-3. As discussed above, the gist of claim 1 is that rather than recycle the aqueous solution comprising ammonium salts, it is diluted, per claim 1, step c) to form a SNCR/SCR solution.
The specification process is the same process taught by Meessen/Mennen and clearly the cited specification portion is discussing the prior art. That is, Meessen teaches that in conventional stripping processes, the initial urea solution (comprising an equilibrium mixture of desired urea and by-product ammonium carbamate, NH3 and CO2) is treated by adjustment of temperature and/or pressure to decompose the ammonium carbamate back to ammonia and carbon dioxide; and upon distillation a top product of pure ammonia and a bottom product of ammonium carbamate/water. Meessen at page 2183, col. 2. And, per the above § 103 rejection, one of ordinary skill is motivated to dilute Meessen’s aqueous ammonium carbamate stream with water for use in Hofmann’s non-catalytic reduction (SNCR) process to the appropriate level. Hofmann at col. 4, lines 38-43.
Regarding the claim 9 limitation of “from 0.01 to 5.0 weight% of urea”, the specification teaches:
In one embodiment, the aqueous composition obtained in step c) comprises urea, in particular from 0.01 to 5.0 weight%, from 0.01 to 2.0 weight% or from 0.01 to 1.0 weight% of urea. The aqueous composition for SNCR/SCR obtained in step c) may comprise urea.
Some equipment used to remove ammonium salts from aqueous solutions comprising urea and ammonium salts may not be completely selective and may remove some urea along with ammonia and carbon dioxide. Urea may also be formed during the separation of ammonia and carbon dioxide from aqueous solutions.
Specification at page 7, lines 19-24 (emphasis added). Thus, the specification effectively teaches that in the proposed practice of Meessen’s process, the bottom aqueous solution of ammonium carbamate in water has a percentage of urea. All the limitations of claim 9 are met by practice of the cited art as proposed because, per the specification,4 one of ordinary skill practicing Meessen in view of Hoffman (i.e., by diluting Meessen’s aqueous ammonium carbamate stream with water for use in Hofmann’s non-catalytic reduction (SNCR) process to the appropriate level) inherently arrives at the claim 9 composition comprising “from 0.01 to 5.0 weight% of urea”, because the required urea percentage is already naturally present. Once a reference teaching product appearing to be substantially identical is made the basis of a rejection, and the examiner presents evidence or reasoning to show inherency, the burden of production shifts to the applicant. MPEP § 2112(V) (citing In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433-34 (CCPA 1977).
Claim 10 is obvious because one of ordinary skill is motivated to employ demineralized water as a diluent to maintain purity as the SNCR/SCR solution will be used to treat effluent.
Conclusion
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ALEXANDER R. PAGANO
Examiner
Art Unit 1692
/ALEXANDER R PAGANO/Primary Examiner, Art Unit 1692
1 In the second-step carbamate decomposition the conversion is to the order of 70%; for every 100 kg of carbamate that is formed, only 70 kg go on to form urea and the rest must be permanently and continuously recycled to reach a complete conversion. R. Lagarrigue, US 2018/0208551 (2018), at pages 2-3, [0053]-[0054].
2 The specification teaches that the three possible salts are ammonium bicarbonate (NH4H(O3), ammonium carbonate ((NH4)2(O3), and ammonium carbamate (NH2CO3NH4). Specification at page 4, lines 3-4.
3 With respect to the claim 2 weight % of nitrogen, expressed as ammonia, the specification teaches:
In one embodiment, the aqueous composition obtained in step c) comprises from 10 to 40 weight%, from 10 to 35 weight%, from 10 to 30 weight%, from 12 to 40 weight%, from 12 to 35 weight%, from 12 to 30 weight%, from 15 to 40 weight%, from 15 to 35 weight%, or from 15 to 30 weight% of nitrogen, expressed as ammonia.
It was found that a nitrogen content of from 10 to 40 weight%, expressed as ammonia, was a suitable SNCR/SCR solution. Furthermore, this content can be obtained from a large majority of streams produced in a plant producing urea.
Specification at page 5, lines 27-32 (emphasis added).
4 It is appropriate to look to the instant specification for evidence that a claimed feature is inherent in the prior art. See, MPEP § 2112.02(I) (discussing Ex parte Novitski, 26 USPQ2d 1389 (Bd. Pat. App. & Inter. 1993) (In Ex parte Novitski the Board rejected a claim directed to a method for protecting a plant from plant pathogenic nematodes by inoculating the plant with a nematode inhibiting strain of P. cepacia. A U.S. patent to Dart disclosed inoculation using P. cepacia type Wisconsin 526 bacteria for protecting the plant from fungal disease. Dart was silent as to nematode inhibition but the Board concluded that nematode inhibition was an inherent property of the bacteria. The Board noted that applicant had stated in the specification that Wisconsin 526 possesses an 18% nematode inhibition rating).
Prosecution Insights