| Patent application number | Description | Published |
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| 20080286188 | Process for the Preparation of a Urea-Comprising Aqueous Stream - The invention relates to a process for the preparation of a urea-comprising aqueous stream, that is suitable for use in a unit for the reduction of NO | 11-20-2008 |
| 20110118506 | PROCESS FOR THE PRODUCTION OF UREA FROM AMMONIA AND CARBON DIOXIDE - Process for the production of urea from ammonia and carbon dioxide in a urea plant containing a high-pressure synthesis section comprising at least one reactor section, a stripper and a condenser wherein all the high-pressure equipment is placed in a low position, wherein the height of the high-pressure section is less than 35 m from ground level and at least one of the reactor sections comprises means for the separate distribution of ammonia in the bottom of the reactor section. | 05-19-2011 |
| 20110160486 | PROCESS FOR THE PRODUCTION OF UREA FROM AMMONIA AND CARBON DIOXIDE - Process for the production of urea from ammonia and carbon dioxide in a urea plant containing a high-pressure synthesis section comprising two reactor sections, a stripper and a condenser, and a recovery section, wherein in the first reactor section a first synthesis solution is formed that is fed to the second reactor section; fresh carbon dioxide is fed to the second reactor section and in the second reactor section a second synthesis solution is formed that is fed to the stripper, wherein the second synthesis solution is stripped with the use of carbon dioxide as stripping gas and the mixed gas stream obtained in the stripper is sent to the condenser together with fresh ammonia and a carbamate stream, whereafter the condensate that is formed in the condenser is fed to the first reactor section and the urea stream that is obtained in the stripper is further purified in the recovery section, wherein the flow of the first synthesis solution from the first reactor section to the second reactor section, the flow of the second synthesis solution from the second reactor section to the stripper, the flow of the mixed gas stream from the stripper to the condenser and of the condensate from the condenser to the first reactor section is a gravity flow. | 06-30-2011 |
| Patent application number | Description | Published |
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| 20080293601 | Method for Preparing an Imidized Polymer - The invention relates to a process for preparing an imidized polymer in a mixing or kneading device, by a reaction of a mixture, comprising a polymer, containing anhydride groups or derivatives thereof and an aromatic polyamine compound, wherein the reaction is carried out in the presence of an acid. With this process an imidized polymer can be obtained with a reduced amount of incomplete reacted anhydride groups with respect to the anhydride groups originally present in the polymer as well as a low amount of free and amid-bound aromatic polyamine. The invention further relates to a solid compound, and in particular a solid multifunctional viscosity modifier comprising a polymer comprising between 0.1 and 10 functional groups per 1000 C-atoms, the functional groups comprising aromatic amine based imide groups, wherein the ratio of imide groups with respect to the functional groups is more than 0.85, preferably more than 0.90 and most preferably more than 0.95 and to a lubricating oil, comprising the multifunctional viscosity modifier according to the invention, wherein the amount of low molecular weight aromatic polyamine in the oil is smaller than 10 ppm. | 11-27-2008 |
| 20100093575 | GRAFT COPOLYMER - The invention relates to a graft copolymer comprising the reaction product of maleic anhydride and a backbone polymer wherein said graft copolymer comprises between 0.50 and 5.0 weight percent of maleic anhydride, wherein said backbone polymer is selected from the group consisting of poly-olefins and copolymers of ethylene and α-olefins with 3 to 8 carbon atoms, the graft copolymer has a MFI of more than 50 dg/min (@190° C., 2.16 kg), and more than 25% of the graft copolymer chains have a chain-end unsaturation. These graft copolymers are suitable as processing aids in e.g. extrusion of high molecular weight polymers. The invention relater also to a method for grafting maleic anhydride to polymers, comprising the steps of: melting an ethylene polymer by heating and down-shearing the polymer in a co- rotating, twin-screw extruder while injecting maleic anhydride and a free radical initiator into a polymer filled, pressurized section of the extruder; and mixing the polymer and the maleic anhydride in the extruder for sufficient time to graft the maleic anhydride wherein the free radical initiator is an organic peroxide that has a half-life (t | 04-15-2010 |
| 20100113315 | Additive composition comprising an amidized or imidized polymer - The invention relates to a process for an additive composition comprising an amidized or imidized polymer. The invention further relates to a highly grafted, multi-functional lubricant additive useful to improve the viscosity index and dispersancy properties of a lubricating oil composition. The present invention also relates to a method of extending lubricant drain intervals and improving fuel economy and fuel economy durability. The additive composition is prepared by: (A) reacting an olefin copolymer of ethylene and at least one C3 to C23 &agr;-olefin comprising from about 15 to 80 mole percent of ethylene, from about 20 to 85 mole percent of said C3 to C23 &agr;-olefin and from about 0 to 15 wt percent of a polyene, said copolymer having a number average molecular weight ranging from 1,000 to 500,000, with an olefinic carboxylic acid acylating agent, said process comprising heating said polymer to a molten condition at a temperature in the range of 60° C. to 240° C., grafting, in a first extruder or a first mixing device, said olefinic carboxylic acylating agent onto said copolymer, optionally subsequently reducing the molecular weight of said copolymer at a temperature in the range of 250° C. to 350° C., thereby producing a grafted, reduced molecular weight acylated copolymer having a number average molecular weight ranging from 1,000 to 80,000 and having at least 0.2-20 molecules of said carboxylic acid acylating agent grafted per 1000 C atoms of said olefin copolymer, and (B) reacting, in a second extruder or a second mixing device, said acylated copolymer made in (A) with a polyamine. | 05-06-2010 |
| 20110021700 | EXTRUSION PROCESS FOR GRAFTING RUBBERS - The invention relates to a process for producing a grafted rubber comprising: a) providing an ethylene propylene rubber having a weight average molecular weight (Mw) of at least 80 kg/mol in a continuous extrusion reactor by feeding the rubber in a slab/melt dosing unit and transporting the rubber to the continuous extrusion reactor by a melt pump; b) drying the rubber in the continuous extrusion reactor to a moisture content of between about 0.2 and about 0.5 wt %; c) providing the dried rubber to a first injection zone of the continuous extrusion reactor at a temperature of between 190 and 250° C., d) in the first injection zone, providing successively a first amount of maleic anhydride and a first free-radical initiator to the dried rubber; e) reacting maleic anhydride with the rubber in a first reaction zone of the continuous extrusion reactor to produce a grafted rubber; f) in a second injection zone, providing successively a second amount of maleic anhydride and a second free-radical initiator, the first and the second free radical initiator is an organic peroxide with a half-life (ty2) of more than 1 second if measured in mono-chlorobenzene at 220° C. g) applying shear to the grafted rubber in a second reaction zone of the continuous extrusion reactor, the shear sufficient to reduce the weight average molecular weight (Mw) of the grafted rubber by a factor of at least 2. | 01-27-2011 |
