US3232985A - Urea synthesis process - Google Patents

Urea synthesis process Download PDF

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US3232985A
US3232985A US246747A US24674762A US3232985A US 3232985 A US3232985 A US 3232985A US 246747 A US246747 A US 246747A US 24674762 A US24674762 A US 24674762A US 3232985 A US3232985 A US 3232985A
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pressure
steam
combined
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Lucien H Cook
Marovic Ivo
Rubin Bernard
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Chemical Construction Corp
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Chemical Construction Corp
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Priority to NL302169D priority Critical patent/NL302169A/xx
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Priority to US246747A priority patent/US3232985A/en
Priority to GB49100/63A priority patent/GB1032440A/en
Priority to NL63302169A priority patent/NL138774B/xx
Priority to FR957879A priority patent/FR1386540A/fr
Priority to ES294808A priority patent/ES294808A1/es
Priority to DE1443623A priority patent/DE1443623C3/de
Priority to BE641762D priority patent/BE641762A/xx
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
    • C07C273/02—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds
    • C07C273/04—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds from carbon dioxide and ammonia
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/10—Process efficiency
    • Y02P20/129—Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/141—Feedstock
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/582—Recycling of unreacted starting or intermediate materials

Definitions

  • This invention relates to the synthesis of urea from ammania and carbon dioxide.
  • An improved and more efficent method for total recycle of unconverted reactants has been developed, which accomplishes direct recycle of the unconverted reactants as a hot gas stream by compression in a multi-stage sequence at an elevated temperature and while in heat exchange with steam.
  • the recycling mixed gas stream is compressed by means of an axial or centrifugal compressor or series of compressors.
  • the gas stream is preferably cooled during compression by heat exchange with process steam, which has been previously bon dioxide are added, and the mixed process stream is cooled by heat exchange with liquid water, mentioned supra, during which a portion of the mixed process stream reacts to form urea under the process conditions of elevated pressure and temperature.
  • the resulting process stream is then passed to a lower pressure level, and a mixed off-gas stream containing ammonia, carbon dioxide and Water vapor is separated from the product aqueous urea solution.
  • the mixed off-gas stream is then recycled to the compressor.
  • one novel aspect of the process of the present invention involves the provision of a plurality of stages of carbamate decomposition and offgas generation at different pressure levels, together with a plurality of compressors having inlet pressures equal to these pressurelevels and outlet pressures corresponding to the next higher pressure level.
  • the off-gas is thus compressed in a cumulative manner in succeeding compressors, until final discharge at urea synthesis pressure.
  • cooling the compressed gas stream in the steam superheater serves to prevent possible ammonia decomposition due to high temperature.
  • the conventional ammonium carbarnate absorption and recycle equipment of the prior art such as high pressure absorption equipment and the carbamate solution recycle pump, have now been eliminated.
  • the extremely large urea synthesis autoclave or reactor of the prior art has also been eliminated, since at high temperature the urea synthesis reaction proceeds rapidly and sufficient retention time is provided in the heat exchanger.
  • the prior art with respect to ammonium carbamate recycle involved heating of the process stream to generate off-gas, which was subsequently condensed to ammonium carbamate using cooling water. The heat of condensation was thereby wasted and in addition cooling water was required.
  • the off-gas is not condensed but instead the gas stream is directly recycled via compression. with external cooling via heat exchange with process steam.
  • the heat of condensation is also recovered at a high temperature level via steam generation from condensate water. Cooling water previously needed for carbamate condensation is no longer required.
  • the generated steam is subsequently superheated via cooling of compressor gas and is expanded through the power recovery steam turbine. External steam requirements are eliminated.
  • Another object is to produce urea in a process in which reaction heat and heat generated through gas compression are recovered as usable high pressure steam.
  • a further object is to synthesize urea in a complete recycle process which achieves substantially complete recovery of heat of reaction and gas compression heating values at usable temperature levels.
  • An additional object is to recycle theoti-gas from a urea synthesis process in an improved and more efficient manner.
  • Still another object is to provide a complete recycle urea process in which outside utility requirements for steam, electricity and cooling Water are substantially reduced or eliminated.
  • ammonia feed stream 1 is compressed by pump 2 to urea synthesis pressure, usually in the range of 2000 p.s.i.g. to'6000 p.s.i.g. Since ammonia at its highest enthalpy state is generally prefenable, the ammonia feed stream 3 may be heated in vaporizer-preheater 4 to provide heated gaseous am monia stream 5 at urea synthesis pressure. Heating the ammonia serves to increase the heat liberated in the autoclave. Thus, the amount of steam generated by heat exchange is thereby increased.
  • Unit 4- will usually be steam heated, with steam entry via 6 and removal of condensate and uncondensed steam via 7.
  • Ammonia stream 5 is added to recycle gas stream 8 to form a mixed process stream 9.
  • Stream 8 is derived from steam superheater 70 at an elevated temperature, and the addition of stream 5 serves to immediately quench stream 8 to a lower temperature level, thereby preventing the decomposition of ammonia in stream 8.
  • Gaseous carbon dioxide feed stream 11 is compressed in compressor 12 to urea synthesis pressure, and the resulting compressed gas 13 is added to stream 9 to form a mixed urea synthesis process stream 14.
  • Stream 14 is thus formed at an elevated pressure in the range of 2000 p.s.i.g. to 6000 p.s.i.g. and a temperature preferably in the range of 350 F. to 500 F.
  • Stream 14 is now passed into heat exchange-reactor unit 15, in which urea synthesis takes place.
  • Unit 15 may be of any suitable design. Thus unit 15 may consist of a tubular heat exchange or boiler, or unit 15 may simply consist of a vessel as shown, provided with an internal coil through which process stream 14 is passed.
  • stream 14 may be formed inside the coil by separate additions of streams 9 and 13, so as to prevent premature urea formation.
  • Stream 14 is cooled in unit 15, to a temperature preferably in the range of 300 F. to 400 F., and leaves as stream 16.
  • stream 16 contains urea, ammonium carbamate, excess ammonia and water.
  • Liquid condensate water is passed into unit 15 via 17 for heat exchange with the process stream, and leaves via 18 as high temperature steam.
  • Stream 16 is now processed so as to recover product aqueous urea solution.
  • inerts are removed from stream 16 in a separator unit of novel design and operation.
  • Stream 16 is passed directly from autoclave unit 15 to inerts separator unit 71, which is a high pressure vessel in which a pressure level is maintained equal to or greater than the autogenous pressure of the liquid stream 16.
  • inerts separator unit 71 which is a high pressure vessel in which a pressure level is maintained equal to or greater than the autogenous pressure of the liquid stream 16.
  • a gaseous stream of inerts plus ammonia, carbon dioxide and water vapor rises from the liquid phase in unit 71.
  • the rising gaseous stream is cooled in packed section 72, provided with cooling jacket 73. Cooling Water is admitted via 74 and discharged via 75.
  • stream 79 is passed through pressure reducing valve 19, leaving as stream 20 at a pressure typically in the range of 12 00 p.s.i.g. to 1700 p.s.i.g.
  • Stream 20 is passed to cyclonic flash separator 21, which is any suitable vessel for separating evolved off-gas from the residual liquid solution.
  • the oft-gas, which is evolved due to pressure reduction is removed from vessel 21 via 22.
  • the residual liquid solution leaves vessel 21 via 23, and is passed through pressure reducing valve 24, leaving as stream 25 at a pressure typically in the range of 600 p.s.i.g. to 850 p.s.i.g.
  • Stream 25 is passed into ammonium carbamate decomposer unit 26, where decomposition of a portion of the ammonium carbamate in the stream is attained by suitable heating.
  • Unit 26 may be of any suitable configuration, with one typical arrangement being shown in the figure.
  • Stream 25 is heated while passing upward through the lower steam-jacketed section of the unit, by steam passing into the jacket via 27 with condensate removal via 28.
  • a portion of the ammonium carbamate present is decomposed to ammonia and carbon dioxide, and further off-gas is separated from residual liquid solution in the upper section of unit 26.
  • the off-gas is removed via 29, while the residual liquid stream with lowered ammonium carbamate content is withdrawn via 30, and is passed through pressure reducing valve 31, leaving as stream 32 at a pressure typically in the range of 275 p.s.i.g. to 500 p.s.i.g.
  • Stream 32 is combined with aqueous recycle stream 33, which is derived in a manner to be described infra.
  • the combined stream 34 is passed into ammonium carbamate decomposer unit 35, Where decomposition of a further portion of the ammonium carbamate in the stream is attained by suitable heating.
  • Unit 35 is similar to unit 26 described supra.
  • stream 34 rises through the lower steam jacketed section of unit 35, which is heated by steam admitted via 36 with condensate removal via 37. The decomposition of most of the remaining ammonium carbamate present in the liquid stream is thus achieved.
  • the mixed off-gas generated in unit 35 is removed via 38, and the residual liquid stream with minor ammonium carbamate content is withdrawn via 39, and is passed through pressure reducing valve 40, leaving as stream 4-1 at a pressure typically in the range of 5 p.s.i.g. to 50 p.s.i.g.
  • Stream 41 is now passed to cyclonic separator 42, which is a unit similar to vessel 21 described supra. Due to the lower pressure level and elevated temperature of the process stream in unit 42, the balance of contained ammonium carbamate is decomposed and evolved via 43 as a mixed oil-gas.
  • the residual liquid stream consisting of product aqueous urea solution is withdrawn via 44 and passed to product utilization.
  • Final off-gas stream 43 is now passed to absorber 45, which is provided with a packed section 46 or other gasliquid contact means.
  • a circulating stream 47 consisting of aqueous absorbent solution is passed into unit above packed section 46, and passes downward countercurrent to the rising gas stream. Ammonia and carbon dioxide from stream 43 are absorbed into the liquid solution.
  • a small stream 40 consisting of makeup water is admitted into the top of unit 45.
  • Stream 49 may be omitted in some cases, depending on the relative proportion of Water in stream 43.
  • the scrubbing solution is removed via 50 from the bottom of unit 45, suitably cooled in cooler 51, removed via 52, and partially recycled via 47 to unit 45.
  • stream 52 is passed via 53 to pump 54, and is compressed to a pressure in the range of 275 p.s.i.g. to 500 p.s.i.g. for recycle via 33.
  • the ammonia and carbon dioxide content of stream 33 is thus recycled to urea synthesis via 38.
  • stream 43 may alternatively be recycled to urea synthesis by gas recompression, as is the case with streams 22, 29 and 38 to be described infra. This alternative is less desirable because of high compression cost for recompression from the low pressure level of stream 43.
  • mixed off-gas stream 38 is passed to unit 55, which is an axial or ccn trifugal compressor of conventional design.
  • the ottgas is compressed to an elevated pressure level equal to that of the off-gas generated in the next higher stage of carbamate decomposition.
  • the resulting compressed olfgas stream 56 is thus combined with off-gas stream 29 produced from unit 26.
  • the combined off-gas stream 57 at a pressure level in the range of 600 p.s.i.g. to 850 p.s.i.g., is now passed into compressor unit 58, which is similar to unit 55 described supra.
  • the resulting compressed oftgas stream 59 is discharged at a pressure level in the range of 1200 p.s.i.g. to 1700 p.s.i.g., and is combined with oilgas stream 22 drived from unit 21.
  • the final combined off-gas stream 60 is now passed into the final compressor unit 10, which is similar to unit 55 described supra.
  • the total combined off-gas stream is compressed to final urea synthesis pressure in the range of 2000 p.s.i.g. to 6000 p.s.i.g.
  • the final compressed oil-gas is discharged via 80, cooled in steam superheater 70, and is recycled to urea synthetsis via 8 in a manner described supra.
  • the general method of gas temperature control during recompression combined with power recovery forms another significant aspect of the present invention.
  • the saturated steam 18 generated by heat exchange with the process stream in synthesis unit is employed to provide both temperature control and power recovery.
  • Steam produced via 18 is passed through unit 58, in heat exchange with the mixed gas stream during compression.
  • the steam is superheated, and serves to lower the temperature of the oil-gas during compression.
  • the steam now leaves unit 58 via 65, and is further superheated by heat exchange with the oil-gas stream in compressor It).
  • the resulting superheated steam is removed from unit 10 via 81, and is further superheated by heat exchange with hot process gas stream in superheater unit '70.
  • condensate may be directly injected into stream to reduce superheat.
  • stream 65 may be desuperheated by heat exchange with condensate.
  • a portion of stream 81 may be diverted for various process heating usages, not shown, such as carbamate decomposition via 2'7 and 36, or for steam tracing.
  • a major portion of stream 81 is superheated in unit 70, removed via 66, and utilized as an energy source in power recovery.
  • stream 66 is expanded through power recovery steam turbine 67, which is linked by shaft coupling 68 with compressor 10.
  • unit 67 serves to provide the required power for operation of unit 10.
  • some smaller power users could be driven by unit 67, not shown.
  • the expanded steam is removed from turbine 67 via 69
  • the steam 69 may be used via 6 to preheat the ammonia feed stream, prior to condensation with cooling water.
  • the resulting condensate water streams 7, 28 and 37, together with condensate derived by condensation of the bal ance of stream 69, are recycled to the steam circuit as condensate water via 17 and 49.
  • off-gas compression sequence described supra is a preferred embodiment of the present invention and forms the most advantageous mode of practice of the process.
  • other compression sequences could also be adapted.
  • streams 3%, 29 and 2;. could be separately compressed up to the final urea synthesis pressure of stream 8, and then combined to form stream 3.
  • This alternative is less advantageous, since the individual compressors must operate over a much greater pressure range and thus are less efficient.
  • the cooling of individual compressors, particularly those compressing low pressure oil-gas could not be satisfactorily accomplished using steam because of the large pressure changes involved.
  • unit 21 and its function may be omitted if desired or replaced by an ammonium carbamate decomposer unit similar to 726.
  • the omission of unit 21 is relatively less desirable, because the extra gas evolution in the steam-jacketed section of unit 26 reduces the heat transfer coefficient thus making unit 26 less efilcient.
  • this variation is also less desirable because proportionatcly more water vapor will be present in the recycling oil-gas stream.
  • stream 8 may be first combined with stream 13, and then with stream 5.
  • Final off-gas stream 43 may also be recycled in difi erent ways.
  • Absorber 45 and its function may alternatively be carried out by means of the process described in U.S. Patent No. 3,038,285, in which case pump 54 may also be omitted.
  • stream 43 may be passed to an off-gas compressor, compressed to the pressure level of stream 38, combined therewith and thus recycled via unit 5'5.
  • Example A urea synthesis process was designed for operation in accordance with the present invention.
  • Basis of the plant sizing was an output of mols/hour of urea.
  • all stream compositions will begiven on the basis of mols/hour of component, based on a plant output of 100 mols/ hour of urea.
  • the urea synthesis feed stream consisted of carbon dioxide, 378 ammonia and 21 water, and was passed into the synthesis reactor unit at 3000 p.s.i.g. Urea synthesis took place while the process stream was in heat exchange with condensate water, thus saturated steam was produced at p.s.i.g. (380 F.)
  • the synthesis melt was discharged at 400 F., and contained 100 urea, 35 carbon dioxide, 178 ammonia and 121 water. Inerts were separated at 3000 p.s.i.g. by vaporization, followed by internal condensation and reflux of carbamate solution. The melt was flashed down to 1500 p.s.i.g. and 350 F, and an oil-gas containing carbon dioxide, 50 ammonia and 3 water was removed at this 1500 p.s.i.g. pressure level. The residual liquid phase, consisting of 100 urea, 25 carbon dioxide, 128 ammonia and 118 water, was now passed to the first stage of steam heated ammonium carbarnate decomposition at 340 F. and 750 p.s.i.g.
  • An off-gas containing carbon dioxide, 77 ammonia and 8 water was removed at this 750 p.s.i.g. pressure stage.
  • the residual liquid phase consisting of 100 urea, 10 carbon dioxide, 51 ammonia and 110 water was reduced in pressure to 375 p.s.i.g. and combined with an aqueous recycle solution containing 2 carbon dioxide, 10 ammonia and 14- water.
  • the combined stream was passed to the second stage of steam heated ammonium carbamate decomposition at 340 F, and 375 p.s.i.g.
  • An olf-gas containing 1.0 carbon dioxide, 51 ammonia and 10 water was removed at this 375 p.s.i.g. pressure stage.
  • the residual liquid phase consisting of 100 urea, 2 carbon dioxide, 10 ammonia and 114 water was now passed to the final stage of ammonium carbamate decomposition and oii-gas removal at 15 p.s.i.g. and 250 F.
  • a product aqueous urea solution containing 100 urea and 100 water was produced at 250 F.
  • the residual final oft-gas produced at 15 p.s.i.g. and 250 F. and containing 2 carbon dioxide, 10 ammonia and 14 water was contacted with an aqueous scrub solution containing these components in the same relative proportion.
  • the recirculating liquid phase was cooled to 100 F. in an external cooler and heated to 125 F. in contact with the condensing off-gas.
  • a portion of the recirculating liquid phase was withdrawn, pressurized from an initial pressure of 15 p.s.i.g. to 375 p.s.i.g. and returned to the process as the aqueous recycle solution described supra.
  • the 375 p.s.i.g. off-gas was compressed to 750 p.s.i.g. and heated from 340 F. inlet to 527 F. outlet in a first compressor.
  • the compressor operated at 72% eificiency with 141,000 Btu/hour work input.
  • the compressed ofi-gas was combined with the 750 p.s.i.g. stage off-gas to give a combined gas stream at 417 F. and 750 p.s.i.g. containing carbon dioxide, 128 ammonia and 18 water.
  • This gas stream was compressed to 1500 p.s.i.g. and heated from 417 F. to 610 F. in a second compressor provided with case cooling, which employed the saturated steam produced at 180 p.s.i.g. in the urea synthesis unit as the cooling medium. Thus an increment of superheat was added to the steam.
  • the compressor operated at 72% efficiency with 430,000 Btu/hour work input.
  • the compressed off-gas was combined with the 1500 p.s.i.g. stage off-gas, to give a combined gas stream at 540 F. and 1500 p.s.i.g. containing carbon dioxide, 178 ammonia and 21 water.
  • This gas stream was compressed to urea synthesis pressure of 3000 p.s.i.g. and heated from 540 F. to 750 F. in a third compressor provided with case cooling.
  • the superheated steam produced by heat exchange in the second compressor was desuperheated by the addition of condensate water, and was then employed as the cooling medium in the third compressor.
  • the final steam produced from the third compressor was obtained at 150 p.s.i.g. and 414 F.
  • the third compressor operated at 72% efliciency with 580,000 Btu/hour work input.
  • the final recycle off-gas stream produced at 3000 p.s.i.g. and 750 F. from the third compressor was cooled to 500 F. in a steam superheater, which served to superheat the steam produced from the third compressor to 720 F.
  • the off-gas stream was then passed to urea synthesis as described supra.
  • Urea synthesis process with total recycle of unconverted process components which comprises compressing input streams of ammonia and carbon dioxide to elevated urea synthesis pressure, combining said input streams with a gaseous recycle stream whereby said recycle stream is quenched and a combined urea synthesis stream is formed at elevated pressure, cooling said combined stream in heat exchange with liquid water whereby said water is vaporized to steam and a portion of said combined stream is converted to urea, heating the resulting stream at reduced pressure to decompose ammonium carbamate, removing off-gas comprising unconverted ammonia and carbon dioxide together with water vapor, recovering a final process stream comprising productaqueous urea solution, compressing said off-gas to urea synthesis pressure in compression means while in heat exchange with said steam, whereby said steam is superheated and said off-gas is also heated to elevated temperature, recycling the compressed ofl-gas stream as said gaseous recycle stream, and expanding said superheated steam through power generating means combined with said compression means whereby power derived from steam expansion is
  • Urea synthesis process with total recycle of unconverted process components which comprises compressing input streams of ammonia and carbon dioxide to elevated urea synthesis pressure, combining said input streams with a gaseous recycle stream whereby said recycle stream is quenched and a combined urea synthesis stream is formed at elevated pressure, cooling said combined stream in heat exchange with liquid water whereby said water is vaporized to steam and a portion of said combined stream is converted to urea, decomposing ammonium carbamate in the resulting stream in a plurality of stages at successively lower pressure, removing off-gas streams comprising unconverted ammonia and carbon dioxide together with water vapor from each stage, recovering a final process stream comprising product aqueous urea solution, compressing said off-gas streams to urea synthesis pressure in compression means while in heat exchange with said steam, whereby said steam is superheated, said oligas streams being combined and heated to elevated temperature, recycling the compressed combined oii-gas stream as said gaseous recycle stream, and expanding said superheated steam through power
  • Urea synthesis process with total recycle of unconverted process components which comprises compressing input streams of ammonia and carbon dioxide to elevated urea synthesis pressure, combining said input streams with a gaseous recycle stream whereby said recycle stream is quenched and a combined urea synthesis stream is formed at elevated pressure, cooling said combined stream in heat exchange with liquid water whereby said water is vaporized to steam and a portion of said combined stream is converted to urea, reducing the pressure of the resulting stream to an intermediate level, removing a first ofi-gas comprising ammonia, carbon dioxide and water vapor,
  • Urea synthesis process with total recycle of unconverted process components which comprises compression input streams of ammonia and carbon dioxide to urea synthesis pressure in the range of 2000 p.s.i.g. to 6000 p.s.i.g., combining said input streams with a gaseous recycle stream whereby said recycle stream is quenched and a combined urea synthesis stream is formed at a temperature in the range of 350 F. to 600 F., cooling said combined stream in heat exchange with liquid water to a temperature in the range of 300 F. to 400 F., whereby said water is vaporized to steam and a portion of said combined stream is converted to urea, reducing the pressure of the resulting stream to the range of 1200 p.s.i.g.
  • NICHOLAS S. RIZZO Primary Examiner.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US246747A 1962-12-24 1962-12-24 Urea synthesis process Expired - Lifetime US3232985A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
NL302169D NL302169A (OSRAM) 1962-12-24
US246747A US3232985A (en) 1962-12-24 1962-12-24 Urea synthesis process
GB49100/63A GB1032440A (en) 1962-12-24 1963-12-12 Urea synthesis process
NL63302169A NL138774B (nl) 1962-12-24 1963-12-18 Werkwijze voor het bereiden van ureum uit ammoniak en kooldioxyde.
FR957879A FR1386540A (fr) 1962-12-24 1963-12-20 Procédé de synthèse de l'urée
ES294808A ES294808A1 (es) 1962-12-24 1963-12-23 Un procedimiento para la síntesis de urea
DE1443623A DE1443623C3 (de) 1962-12-24 1963-12-23 Verfahren zur Herstellung von Harnstoff
BE641762D BE641762A (OSRAM) 1962-12-24 1963-12-24

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BE (1) BE641762A (OSRAM)
DE (1) DE1443623C3 (OSRAM)
ES (1) ES294808A1 (OSRAM)
GB (1) GB1032440A (OSRAM)
NL (2) NL138774B (OSRAM)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3357901A (en) * 1964-10-16 1967-12-12 Toyo Koatsu Ind Inc Ammonia, carbon dioxide recovery from urea synthesis utilizing an ejector
US3506710A (en) * 1966-10-14 1970-04-14 Toyo Koatsu Ind Inc Urea synthesis process with solution recycle
US3593491A (en) * 1969-05-21 1971-07-20 Fluor Corp Ammonia plant carbon dioxide absorption and compression

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110590605B (zh) * 2019-10-11 2021-08-24 重庆化工职业学院 一种氨基甲酸甲酯的生产方法

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1429483A (en) * 1920-07-09 1922-09-19 Basf Ag Process of manufacturing urea
FR58503E (fr) * 1945-03-15 1954-01-27 Gobey Lab Procédé d'isomérisation de corps appartenant à la série du phénylchromane
US3155722A (en) * 1960-01-29 1964-11-03 Chemical Construction Corp Recovery of residual ammonia and carbon dioxide in the synthesis of urea

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1429483A (en) * 1920-07-09 1922-09-19 Basf Ag Process of manufacturing urea
FR58503E (fr) * 1945-03-15 1954-01-27 Gobey Lab Procédé d'isomérisation de corps appartenant à la série du phénylchromane
US3155722A (en) * 1960-01-29 1964-11-03 Chemical Construction Corp Recovery of residual ammonia and carbon dioxide in the synthesis of urea

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3357901A (en) * 1964-10-16 1967-12-12 Toyo Koatsu Ind Inc Ammonia, carbon dioxide recovery from urea synthesis utilizing an ejector
US3506710A (en) * 1966-10-14 1970-04-14 Toyo Koatsu Ind Inc Urea synthesis process with solution recycle
US3593491A (en) * 1969-05-21 1971-07-20 Fluor Corp Ammonia plant carbon dioxide absorption and compression

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Publication number Publication date
BE641762A (OSRAM) 1964-06-24
DE1443623A1 (de) 1968-10-31
DE1443623B2 (de) 1973-07-26
NL302169A (OSRAM) 1900-01-01
GB1032440A (en) 1966-06-08
NL138774B (nl) 1973-05-15
DE1443623C3 (de) 1974-02-28
ES294808A1 (es) 1964-06-01

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