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8927770 High-yield process for the synthesis of urea  
A process for the direct synthesis of urea from ammonia and carbon dioxide at high pressures and temperatures, with the formation of ammonium carbamate as intermediate, comprising a decomposition...
8481786 Systems and methods for integrated ammonia-urea process  
Methods for producing urea are provided. A method for producing urea can include exchanging heat from a syngas comprising hydrogen and carbon dioxide to a urea solution comprising urea and...
8383856 Process for urea production and related plant  
A process for urea production from ammonia and carbon dioxide, made to react at a predetermined high pressure in an appropriate synthesis reactor (112), from the reaction between NH3 and CO2 being...
8377399 Process for increasing the capacity of an existing urea plant  
Process for increasing the capacity of an existing urea plant comprising a high-pressure urea synthesis section and one or more recovery sections, wherein next to the existing urea plant a urea...
7732640 Process for urea production from ammonia and carbon dioxide  
A process for urea production comprises a first process step in which ammonia (7) and carbon dioxide (6) are obtained, subjecting natural gas (1) to reforming treatments (12, 14), and a second...
7674933 Method for modernizing a urea production plant  
A method for modernizing a urea production plant including a urea synthesis reactor, a stripping unit and at least one condensation unit. The method includes providing: means in the condensation...
7642377 Systems and methods for integrated ammonia-urea process  
Systems and methods for producing urea are provided. A method for producing urea can include exchanging heat from a syngas comprising hydrogen and carbon dioxide to a urea solution comprising urea...
7619114 Method for the modernization of a urea production plant  
A method for revamping a urea plant of the type comprising a synthesis section (2) having a urea synthesis reactor (5), a thermal stripping unit (7) and at least one horizontal condensation unit...
7279599 Carbamate condensation method and unit for carrying out such a method  
Method for carbamate condensation of a carbon dioxide/ammonia gaseous phase in a liquid phase in a condensation unit of the so-called submerged type comprising a heat exchange tube bundle having a...
7220882 Process for urea production and plant  
In a process for urea production of the type comprising the reaction between ammonia and carbon dioxide in a high-pressure reactor followed by an autothermal stripping of the resulting reaction...
7094927 Process for increasing the capacity of a urea plant  
Process for increasing the capacity of a urea plant comprising a compression section, a high-pressure synthesis section, a urea recovery section, in which a urea melt is formed, and optionally a...
6855846 Process for the preparation of urea  
Process for the preparation of urea from ammonia and carbon dioxide in which all or part of the liquid ammonia needed for the process is supplied to the high-pressure scrubber in such a way that...
6730811 Process for the preparation of urea  
The invention relates to a process for the preparation of urea from ammonia and carbon dioxide in which the low-pressure carbamate stream formed in the further upgrading of the urea synthesis...
6696026 Process for combined production of ammonia and urea  
A process for the combined production of ammonia and urea of the type comprising an ammonia synthesis reactor (2), a urea synthesis reactor (5) and a urea recovery section (21) stands out for the...
6680407 Installation and process for the preparation of urea  
The invention relates to an installation for the preparation of urea from ammonia and carbon dioxide, the installation comprising two reactor sections in a vertically placed combined reactor and a...
6649795 Process for decomposing a carbamate aqueous solution coming from the urea recovery section of a urea production plant  
In a process for decomposing a carbamate aqueous solution coming from a urea recovery section of a urea production plant at a predetermined temperature by indirect heat exchange with a heating...
6552224 Process and plant for the production of urea  
A process for urea production in a synthesis loop based on CO2 stripping is distinguished by the fact that at least part of a flow recycle carbamate is sent to a treatment of carbamate...
6538157 Method for the preparation of urea  
A method for the preparation of urea in a reactor using ammonia and carbon dioxide as starting materials, includes a) bringing the ammonia and carbon dioxide into contact in the reactor under...
6344588 Process for the preparation of urea  
In the present process for the preparation of urea, an off-gas stream released during the synthesis of melamine in a high-pressure melamine process which consists predominantly of ammonia and...
6287525 Process and plant for urea production with reaction spaces having differentiated yields  
In a process for urea production, substantially pure ammonia and carbon dioxide are reacted in a main reaction space from which outgoes a reaction mixture subjected to stripping to obtain a...
6118023 Method for increasing the capacity of an existing urea process  
Method for increasing the capacity of an existing urea process, the existing urea process comprising a reactor (R), a pressure-reduction section (SC) and a urea-recovery section (U), characterized...
5767313 Method for the preparation of urea  
The present invention relates to a process and apparatus for the preparation of urea, and in particular for urea obtained from ammonium carbamate formulated from carbon dioxide and ammonia at a...
5750780 Process for the synthesis of urea comprising two separate reaction zones  
A process for the synthesis of urea starting from ammonia and carbon dioxide, comprising a reaction step carried out in at least two distinct operating zones basically at the same pressure, but...
5597454 Process for producing urea  
A urea production process combining lower pressure urea concentration and carbamate recovery steps into a single non-vacuum operation. Following high pressure stripping wherein a bulk of unreacted...
5523482 Process and plant for the production of urea in reaction spaces with different yields  
In a process of producing urea in which ammonia and carbon dioxide are reacted in a first reaction space (E-1, R-1) the unreacted carbamate present in the reaction mixture is subjected to a...
5359140 Urea production process of high energy efficiency  
A urea production process in which the urea solution produced in the reaction zone is treated in sequence with a first thermal decomposer at the same pressure as the reaction, to decompose part of...
5316554 Method for processing crystalline ammonium carbamate  
Ammonium carbamate, in solution with urea, water and ammonia and under high temperature and pressure is cooled to below its crystallization temperature while being subjected to an elevated...
4988491 Flexible integration of the production of ammonia and urea  
The process of the present invention which produces the flexible integration for the production of ammonia and urea uses adiabatic reforming of the carbonaceous feedstock such as natural gas. With...
4613697 Process for the displacement to the gaseous phase of the excess of NH3  
A process for the displacement to the gaseous phase, at 80-250 Kg/cm2, of the excess NH3 contained in an aqueous urea solution, coming, at 150°-230° C., from a former stripping, isobaric with the...
4382800 Free amine-containing polymeric dyes  
Soluble polymeric colorants composed of free amine groups and chromophoric groups covalently bonded to an organic backbone are disclosed. The number of free amine groups is not less than one-half...
4320103 Flexible integrated method for the production of ammonia and urea  
In an integrated flexible installation for producing ammonia and urea, the improved method which consists in that a portion of the gaseous stream comprising carbon dioxide, hydrogen and nitrogen...
4291006 Combined process for the production of urea and ammonia  
In an integrated or combined process for the production of ammonia and urea, the improvement consisting in that the absorption of CO2 from the raw gas going to the synthesis reactor for ammonia is...
4154760 Process for controlling the temperature during urea synthesis  
A urea synthesis process for converting ammonia and carbon dioxide to urea is improved by providing an easy means of maintaining the urea synthesis zone in the process at a constant temperature....
4138434 Integrated ammonia-urea producing process, for the production of urea  
An improvement of the SNAM ammonia-stripper integrated urea process is disclosed, wherein a gaseous stream obtained by decomposing hydrocarbons is fed to an adiabatic ammonia stripper placed...
4094903 Urea synthesis with improved heat recovery and conversion  
Heat recovery and conversion of reactants to urea are improved in adiabatic and in isothermal urea synthesis systems. Ammonia and carbon dioxide reactor feed streams are charged to a first heat...
4087513 Method of hydrolyzing urea contained in waste water streams  
A process for hydrolyzing urea in waste water streams which comprises introducing a waste water stream containing urea into a carbon dioxide recovery system such as used in connection with the...
4066693 Process for the preparation of urea  
A process for preparing urea by the intermediate formation of ammonium carbamate is disclosed, wherein the process involves reduced use of high pressure steam, and the reduced production, as a...
4061675 Process for the synthesis of urea from carbon dioxide and ammonia  
Urea is produced from ammonia synthesis effluent containing hydrogen, nitrogen, methane and argon, which is reacted with carbon dioxide to form ammonium carbamate. The hot ammonia synthesis...
4042626 Integrated two-stage urea synthesis  
Urea synthesis in two stages, in which the first stage of ammonium carbamate formation is in indirect heat exchange with the second stage of ammonium carbamate dehydration to synthesize urea....
4012443 Integrated urea-ammonia process  
Improved integrated process for simultaneous synthesis of ammonia and urea. Improved yields of urea in purified form are obtained by a simple process which curtails the addition of external water...
4001320 Method for controlling the ammonia and CO2 ratios in a urea manufacturing process  
A process for urea manufacture is described wherein the molar ratio of unreacted NH3 to CO2 (including NH3 and CO2 in the form of ammonium carbamate) in the carbamate reaction liquid phase is...
3708536 RECYCLING MELAMINE SYNTHESIS OFFGAS TO UREA SYNTHESIS  
3544628 UREA SYNTHESIS  
3539627 PROCESS FOR PRODUCTION OF UREA  
3524722 REMOVAL OF CARBON DIOXIDE FROM NATURAL GAS  
3356723 Preparation of urea  
3349126 Integrated ammonia and urea process  
3270051 Dual step urea production  
3105093 Process and apparatus for preparing urea from nh3 and co2  
3072721 Production of urea from ammonia and co2  

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