US20070032650A1 - Integrated process for urea and melamine production - Google Patents

Integrated process for urea and melamine production Download PDF

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Publication number
US20070032650A1
US20070032650A1 US10/595,349 US59534904A US2007032650A1 US 20070032650 A1 US20070032650 A1 US 20070032650A1 US 59534904 A US59534904 A US 59534904A US 2007032650 A1 US2007032650 A1 US 2007032650A1
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US
United States
Prior art keywords
urea
section
melamine
aqueous solution
plant
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US10/595,349
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English (en)
Inventor
Paolo Brunengo
Federico Zardi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Casale SA
Koninklijke Philips NV
Original Assignee
Urea Casale SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Urea Casale SA filed Critical Urea Casale SA
Assigned to KONINKLIJKE PHILIPS ELECTRONICS N.V. reassignment KONINKLIJKE PHILIPS ELECTRONICS N.V. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KOHLER, THOMAS, NIELSEN, TIM
Assigned to UREA CASALE S.A. reassignment UREA CASALE S.A. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BRUNENGO, PAOLO, ZARDI, FEDERICO
Publication of US20070032650A1 publication Critical patent/US20070032650A1/en
Priority to US11/777,842 priority Critical patent/US7414130B2/en
Abandoned legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D251/00—Heterocyclic compounds containing 1,3,5-triazine rings
    • C07D251/02—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings
    • C07D251/12—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members
    • C07D251/26—Heterocyclic compounds containing 1,3,5-triazine rings not condensed with other rings having three double bonds between ring members or between ring members and non-ring members with only hetero atoms directly attached to ring carbon atoms
    • C07D251/40—Nitrogen atoms
    • C07D251/54—Three nitrogen atoms
    • C07D251/56—Preparation of melamine
    • C07D251/60—Preparation of melamine from urea or from carbon dioxide and ammonia
    • 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
    • C07C273/12—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 combined with the synthesis of melamine
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00002—Chemical plants
    • B01J2219/00004—Scale aspects
    • B01J2219/00006—Large-scale industrial plants
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
    • B01J2219/00092—Tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2219/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J2219/00049—Controlling or regulating processes
    • B01J2219/00051—Controlling the temperature
    • B01J2219/00074—Controlling the temperature by indirect heating or cooling employing heat exchange fluids
    • B01J2219/00087—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor
    • B01J2219/00103—Controlling the temperature by indirect heating or cooling employing heat exchange fluids with heat exchange elements outside the reactor in a heat exchanger separate from the reactor
    • 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
    • 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

  • the present invention relates to a process for the integrated production of urea and melamine.
  • the present invention concerns a process of the above-identified type, wherein urea is produced in a urea plant comprising a high pressure urea synthesis section and a urea recovery section and wherein the off-gases resulting as by-products of the melamine synthesis are recycled to said high pressure urea synthesis section.
  • high pressure urea synthesis section it is intended to mean a section operated at a pressure of at least about 120 bar, generally between 130-260 bar.
  • the process according to the present invention is of the type wherein the off-gases to be recycled have a pressure of at least 2 bar, generally between 2 and 30 bar.
  • the present invention is also concerned with an integrated plant for carrying out such a process.
  • melamine is produced in a plant, so called melamine plant, using—as raw materials (reactants)—NH 3 and urea, the latter being produced in a plant for urea production, so called urea plant, to which the off-gases coming from the melamine plant and substantially containing NH 3 and CO 2 , are recycled as raw materials (reactants).
  • the off-gases are appropriately treated before being fed into the urea plant.
  • the off-gases are condensed, at a pressure equal or lower than their discharge pressure, with a weak ammonia aqueous solution (ammonia concentration comprised between 0 to 15% by weight).
  • a weak ammonia aqueous solution ammonia concentration comprised between 0 to 15% by weight.
  • the so obtained off-gas liquid solution is then fed to a waste water treatment section of the urea plant, generally operated at a pressure of about 2-5 bar, where NH 3 and CO 2 are recovered from the aqueous solution and recycled to the high pressure urea synthesis section, through the low pressure urea recovery section of the urea plant.
  • the technical problem underlying the present invention is to provide an integrated process for urea and melamine production having functional features such as to fully overcome the drawbacks set forth with respect to the prior art, wherein urea is produced at higher conversion yield and with lower energy consumption.
  • urea is produced in a urea plant comprising a high pressure urea synthesis section and a urea recovery section for separating urea from a carbamate aqueous solution
  • melamine is produced in a melamine plant wherein off-gases resulting as by-products of the melamine synthesis are discharged therefrom at a pressure of at least 2 bar and recycled to said high pressure urea synthesis section
  • the process being characterized in that it further comprises the steps of:
  • the process according to the present invention advantageously further comprises the step of:—compressing said carbamate aqueous solution coming from said urea recovery section to a pressure substantially corresponding to the operating pressure of said off-gas condensation section, previous to feeding it in such a section.
  • the process according to the present invention advantageously further comprises the step of:—compressing said concentrated carbamate aqueous solution coming from said off-gas condensation section to a pressure substantially corresponding to the operating pressure of said high pressure urea synthesis section, previous to feeding it in such a section.
  • the main advantage resulting by the process according to the present invention is that condensation of the off-gases is performed by exploiting the low amount of water already contained in the carbamate aqueous solution obtained in the urea recovery section of the urea plant and which is anyway recycled to the high pressure urea synthesis section. Therefore, contrary to the processes of the prior art—no additional amount of water is added to the off-gasses when recycling them from the melamine plant to the urea plant.
  • FIG. 1 schematically shows an integrated plant for urea and melamine production according to the process of the present invention
  • FIG. 2 schematically shows a detail of the integrated plant for urea and melamine production of FIG. 1 .
  • the integrated plant 10 comprises a plant 11 for the production of melamine and a plant 12 for the production of urea
  • the melamine plant 11 of the present invention can be of the catalytic low pressure type (up to 70 bar) or of the non-catalytic high pressure type (above 70 bar), provided that the off-gases discharged from the melamine plant have a pressure of at least 2 bar.
  • the plant 11 comprises a low pressure or high pressure melamine synthesis section 13 .
  • the melamine plant 11 is of the non-catalytic high pressure type, wherein the off-gases discharged as by-products of the melamine synthesis have a pressure comprised between 3 and 30 bar, preferably between 20 and 25 bar.
  • the off-gasses discharged from the melamine plant according to the present invention can also have a much higher pressure, depending on the pressure at which melamine is produced.
  • the urea plant 12 of the present invention is of the total recycle type, wherein urea is produced at a pressure of at least 120 bar, generally at about 130-260 bar, in a high pressure urea synthesis section 15 in fluid communication with a urea recovery section 16 .
  • the urea recovery section 16 comprises (not shown) a medium pressure recovery section, operating at a pressure of about 15-30 bar and/or a low pressure recovery section, operating at a pressure of about 2-10 bar.
  • the urea plant 12 is of the so called CO 2 or ammonia stripping type, with the high pressure urea synthesis section 15 operated at about 130-170 bar and comprising at least one urea synthesis reactor, stripper and carbamate condenser (not shown), connected one to the other so as to form a substantially isobaric loop.
  • the high pressure urea synthesis section 15 operated at about 130-170 bar and comprising at least one urea synthesis reactor, stripper and carbamate condenser (not shown), connected one to the other so as to form a substantially isobaric loop.
  • the urea plant 12 of the present invention is of the CO 2 stripping type and the urea recovery section 16 only includes the low pressure section.
  • the integrated plant 10 further comprises an off-gas condensation section 17 arranged between the plant 11 for melamine production and the plant 12 for urea production.
  • the off-gas condensation section 17 is in fluid communication with the melamine synthesis section 13 , the urea recovery section 16 and the high pressure synthesis section 15 .
  • the off gas condensation section 17 comprises at lest one condenser apparatus 40 , which in the present example comprises a tube bundle 41 heat exchanger.
  • the integrated plant 10 of the invention optionally further comprises a first compression section 18 , arranged between and in fluid communication with the urea recovery section 16 and the off-gas condensation section 17 , and a second compression section 19 , arranged between and in fluid communication with the off-gas condensation section 17 and the high pressure urea synthesis section 15 .
  • Compression sections 18 and 19 generally comprise at least one compressor or pump (not shown) for liquid flow of the conventional type.
  • CO2 and ammonia are fed to the high pressure urea synthesis section 15 of the urea plant 12 through flow line 30 .
  • Section 15 is also fed with a flow of concentrated carbamate aqueous solution, which will be described in greater details in the following description, through flow line 31 .
  • the above reactants are made to react and a urea solution comprising urea, ammonium carbamate, free ammonia and water is obtained.
  • the urea solution leaves section 15 through flow line 32 and is fed to the urea recovery section 16 , where it is further treated in order to separate urea from the other components of the solution (mainly water and unconverted reactants).
  • a concentrated urea solution for instance comprising about 70% by weight of urea, is then discharged, through line 33 , from the urea recovery section 16 and at least in part used as reactant in the plant 11 for melamine production.
  • urea is fed to the melamine synthesis section 13 of the melamine plant 11 in the form of melt urea coming from a urea finishing section (not shown) provided downstream to the urea recovery section 16 .
  • the concentrated urea solution, or a portion thereof, is fed, through line 34 , to the melamine synthesis section 13 .
  • the concentrated urea solution is fed, through line 35 , to a concentration section (not shown) of the urea plant 12 for further urea purification in order to produce for instance urea prills or granules.
  • section 13 can optionally also be fed with an additional flow of ammonia, indicated in FIG. 1 by flow line 14 .
  • a melamine solution is discharged, through line 36 , for further processing such as cooling (not shown), where melamine is converted into a powder and exits the plant 11 .
  • CO 2 and NH 3 off-gases are also obtained in section 13 , as by-products of the melamine synthesis and leaves section 13 through flow line 37 .
  • the off-gases are suitably washed (scrubbed), not shown, with the feed concentrated urea solution in order to remove possible liquid melamine entrained in such gases.
  • the so obtained off-gases are then fed, through flow line 37 , to the off-gas condensation section 17 of the integrated plant 10 of the present invention.
  • the off-gas condensation section 17 is further advantageously fed with a carbamate aqueous solution coming from the urea recovery section 16 of the urea plant 12 , through a flow line 38 .
  • This carbamate aqueous solution comprises at least part of the above-mentioned water and the unconverted reactants that have been separated from the urea solution in the urea recovery section 16 .
  • a solution is commonly called recycle carbamate solution since it is the solution that is recycled (suitably compressed) to the high pressure urea synthesis section.
  • An example of composition of the carbamate aqueous solution according to the present invention comprises: 20-40% by weight of ammonia, 20-40% by weight of CO 2 and the rest water. The amounts of these components can vary depending on the urea synthesis process.
  • the off-gas condensation section 17 is operated at substantially the same pressure as the pressure of the off-gases leaving the melamine synthesis section 13 .
  • the latter is advantageously compressed in the first compression section 18 to the pressure of such off-gases i.e. to the operating pressure of the off-gas condensation section 17 .
  • the off-gases coming from the melamine synthesis section 13 and the carbamate aqueous solution coming from the urea recovery section are mixed together and fed through line 39 to the condenser apparatus 40 .
  • the condenser apparatus 40 the off-gases are completely condensed (apart for a negligible amount of inert components non condensable) in the carbamate aqueous solution by indirect heat exchange with a cooling fluid (such as water), thus advantageously obtaining a concentrated carbamate aqueous solution.
  • the mixture of off-gases and carbamate aqueous solution fed to the condenser apparatus 40 is made to flow on the external side of the tube bundle 41 (mantel side), while the cooling fluid, which is fed to the condenser apparatus 40 through line 42 and is discharged therefrom through line 43 , is made to flow within the tube bundle 41 (tube side).
  • the off-gases and the carbamate aqueous solution can be mixed together before being fed to the off-gas condensation section 17 or they can be fed directly and separately to the condenser apparatus 40 , without being previously mixed.
  • the so obtained concentrated carbamate aqueous solution is then recycled to the high pressure synthesis section 15 through flow line 31 , while the negligible amount of uncondensed inert components exits the condenser apparatus 40 through line 44 .
  • the concentrated carbamate aqueous solution is recycled to one of the unit presents in the high pressure synthesis section 15 , such as the synthesis reactor, the stripper or the carbamate condenser.
  • the operating pressure of the high pressure synthesis section 15 be higher than the operating pressure of the off-gas condensation section 17 , then the concentrated carbamate aqueous solution leaving such a condensation section 17 is advantageously compressed in the second compression section 19 to the operating pressure of the urea synthesis section 15 .
  • the flow lines indicated in FIGS. 1 and 2 by reference signs 14 , 30 - 39 , 42 - 44 schematically represent connecting ducts or pipes of conventional type.
  • the plant 10 described above is particularly suitable for carrying out the integrated process for urea and melamine production according to the present invention, wherein urea is produced in the urea plant 12 comprising the high pressure urea synthesis section 15 and the urea recovery section 16 for separating urea from a carbamate aqueous solution, and melamine is produced in the melamine plant 11 wherein off-gases resulting as by-products of the melamine synthesis are discharged therefrom at a pressure of at least 2 bar and recycled to said high pressure urea synthesis section 15 , the process being characterized in that it further comprises the steps of:
  • the present process can be suitable carried out also for the revamping or retrofitting of pre-existing urea and melamine plants as well as for the modification of pre-existing integrated plants for urea and melamine production.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US10/595,349 2004-02-20 2004-08-10 Integrated process for urea and melamine production Abandoned US20070032650A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US11/777,842 US7414130B2 (en) 2004-02-20 2007-07-13 Integrated process for urea and melamine production

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP2004001718 2004-02-20
EP2004/001718 2004-02-20
PCT/EP2004/008943 WO2005080321A1 (en) 2004-02-20 2004-08-10 Integrated process for urea and melamine production

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2004/008943 A-371-Of-International WO2005080321A1 (en) 2004-02-20 2004-08-10 Integrated process for urea and melamine production

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US11/777,842 Continuation US7414130B2 (en) 2004-02-20 2007-07-13 Integrated process for urea and melamine production

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US20070032650A1 true US20070032650A1 (en) 2007-02-08

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US10/595,349 Abandoned US20070032650A1 (en) 2004-02-20 2004-08-10 Integrated process for urea and melamine production
US11/777,842 Active 2024-09-05 US7414130B2 (en) 2004-02-20 2007-07-13 Integrated process for urea and melamine production

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US (2) US20070032650A1 (ar)
EP (1) EP1716111B2 (ar)
CN (1) CN1902163B (ar)
CA (1) CA2553794A1 (ar)
RU (1) RU2344125C2 (ar)
SA (1) SA05260022B1 (ar)
UA (1) UA87133C2 (ar)
WO (1) WO2005080321A1 (ar)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100069631A1 (en) * 2006-11-04 2010-03-18 Urea Casale S.A. Integrated Process for Urea and Melamine Production

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2606784C (en) * 2005-05-13 2013-07-30 Dsm Ip Assets B.V. Method for concentrating an aqueous ammonium carbamate stream
US7897568B2 (en) * 2006-03-03 2011-03-01 Vinay K. Singh Compositions for treatment of cancer
EP2098516A1 (en) * 2008-03-04 2009-09-09 Urea Casale S.A. Process for the production of high purity melamine from urea
EP2107051A1 (en) * 2008-04-02 2009-10-07 DSM IP Assets B.V. Process for inreasing the capacity of an existing urea plant
EP2502905A1 (en) * 2011-03-24 2012-09-26 Borealis Agrolinz Melamine GmbH Method for treating offgases from a melamine plant
EP2940006A1 (en) * 2014-04-28 2015-11-04 Casale Sa Process and plant for the synthesis of urea and melamine
EP3053915A1 (en) * 2015-02-06 2016-08-10 Casale SA Method for revamping a high pressure melamine plant
WO2016171562A1 (en) 2015-04-23 2016-10-27 Stamicarbon B.V. Method and system for the integrated production of urea and melamine
EP4098356A1 (en) * 2018-01-26 2022-12-07 Casale Sa Plant and process for the synthesis of melamine with offgas recovery in a tied-in urea plant
EP3766865A1 (en) 2019-07-18 2021-01-20 Casale Sa A process for the synthesis of urea
CN114573482A (zh) 2020-11-30 2022-06-03 欧洲技术三聚氰氨股份公司 三聚氰胺和尿素生产的一体化方法
WO2024080874A1 (en) 2022-10-14 2024-04-18 Stamicarbon B.V. Urea and melamine production

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US6114579A (en) * 1996-08-30 2000-09-05 Dsm. N.V. Process for the preparation of urea
US6586629B1 (en) * 1998-12-03 2003-07-01 Agrolinz Melamin Gmbh Method of introducing melamine off-gases into a urea plant
US7094927B2 (en) * 2002-07-29 2006-08-22 Dsm Ip Assets B.V. Process for increasing the capacity of a urea plant

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BE615692A (ar) * 1961-03-29 1900-01-01
GB1148767A (en) * 1965-10-25 1969-04-16 Nissan Chemical Ind Ltd Process for the production of melamine
DE2053358A1 (en) * 1970-10-30 1972-05-04 Badische Anilin & Soda Fabrik AG, 6700 Ludwigshafen Supply of waste gases for ureau synthesis - using a controlled ammonia to carbon dioxide ratio
TW385307B (en) * 1996-08-30 2000-03-21 Dsm Nv Process for the preparation of urea
ITMI20021026A1 (it) 2002-05-14 2003-11-14 Eurotecnica Dev & Licensing S Processo di produzione di melammina da urea e particolarmente per ottenere off-gas privi di melammina nello stadio di prima separazione

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
US6114579A (en) * 1996-08-30 2000-09-05 Dsm. N.V. Process for the preparation of urea
US6586629B1 (en) * 1998-12-03 2003-07-01 Agrolinz Melamin Gmbh Method of introducing melamine off-gases into a urea plant
US7094927B2 (en) * 2002-07-29 2006-08-22 Dsm Ip Assets B.V. Process for increasing the capacity of a urea plant

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100069631A1 (en) * 2006-11-04 2010-03-18 Urea Casale S.A. Integrated Process for Urea and Melamine Production
US9765041B2 (en) 2006-11-04 2017-09-19 Casale Sa Integrated process for urea and melamine production

Also Published As

Publication number Publication date
UA87133C2 (ru) 2009-06-25
CN1902163B (zh) 2010-05-26
SA05260022B1 (ar) 2009-10-26
EP1716111A1 (en) 2006-11-02
US7414130B2 (en) 2008-08-19
CA2553794A1 (en) 2005-09-01
CN1902163A (zh) 2007-01-24
US20070282102A1 (en) 2007-12-06
RU2344125C2 (ru) 2009-01-20
WO2005080321A1 (en) 2005-09-01
RU2006133459A (ru) 2008-03-27
EP1716111B1 (en) 2013-12-18
EP1716111B2 (en) 2022-06-08

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AS Assignment

Owner name: KONINKLIJKE PHILIPS ELECTRONICS N.V., NETHERLANDS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NIELSEN, TIM;KOHLER, THOMAS;REEL/FRAME:017451/0291

Effective date: 20041006

AS Assignment

Owner name: UREA CASALE S.A., SWITZERLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BRUNENGO, PAOLO;ZARDI, FEDERICO;REEL/FRAME:017845/0061

Effective date: 20060615

STCB Information on status: application discontinuation

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