Class 159/47.2 - Involving urea

Subclass of Class 159 - Concentrating evaporators
Definition: Processes wherein an urea containing material is concentrated.
No. of patents: 20
Last issue date: 11/06/2012

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Number	Title	Issue Date
8303766	Method and device for evaporating a fluid A method and device for evaporating a predeterminable volume of fluid includes successive addition of partial volumes of the predeterminable volume to a supply line at different adding rates, at least partially evaporating the partial volumes forming vapor film betw...	11/06/2012
6528594	Flowable glanulates A process for the manufacture of a flowable granulate by means of spray granulation, which comprises using as starting material a formulation in liquid form comprising (a) a substance or a mixture of substances that is in the form of a waxy or cohesive so...	03/04/2003
6334984	Hydrolysis reactor for removal of urea, ammonia and carbon dioxide from a liquid phase comprising urea in aqueous solution A hydrolysis reactor for removal of urea, ammonia and carbon dioxide from a liquid phase comprising urea in aqueous solution advantageously comprises a dividing baffle extending horizontally at a preset height in the reactor in which it defines a first an...	01/01/2002
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 partially purified mixture sent to a urea recovery section. From ...	09/11/2001
6165315	Reactor for the synthesis of urea A reactor for the synthesis of urea from ammonia and carbon dioxide at elevated temperature and pressure is provided with perforated reactor trays in which at least a pair of spaced part perforated reactor trays each have at least one opening at least a d...	12/26/2000
5744009	Method and apparatus for recovering condensables in vapor from a urea vacuum evaporator An improved urea recovery process is presented. In the improved process, multiple vacuum rated surface condensers used to condense water vapor evolved during urea vacuum evaporation/concentration are replaced by a direct contact cooler/absorber to obtain ...	04/28/1998
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 carbamate is recovered from the reaction effluent, remaini...	01/28/1997
5273623	Process for concentrating urea solution under vacuum Process for vacuum-concentrating urea solutions in which the final step of evaporation of the urea solution under vacuum is carried out within the injection of overheated water vapor in the overhead portion of the concentrator, in order to counteract the ...	12/28/1993
5176800	Process for the modernization of existing urea plants and a modernized urea plant A process to modernize existing urea plants which use a stripping with carbon dioxide, and to increase urea yields and flexibility under overload conditions while at the same time reducing energy consumption, corrosion phenomena and possible risks of expl...	01/05/1993
4758311	Method for avoiding the corrosion of the strippers in the urea manufacturing plants A method for passivating the surface of the strippers of the urea plants, where the temperatures are very high, where the pressures range from 120 to 240 Kg/cm2 and where the effluent process flow from the synthesis reactor undergoes one or mor...	07/19/1988
4747915	Falling-film process for the cocurrent evaporation of a solution A falling-film process and apparatus for the cocurrent evaporation of a solution is disclosed. The process utilizes a tube-bundle heat exchanger in which the upper ends of the individual tubes of the tube-bundle are closed. Apertures, preferably in the fo...	05/31/1988
4701353	Process for the preparation of granules Preparation of granules by making nuclei grow, in a fluidized bed, by causing a liquid material to solidify thereon. The liquid material is sprayed in the bed upwards, with the aid of a spraying device provided with a central channel through which the liq...	10/20/1987
4619843	Process for the preparation of granules Preparation of granules by making solid nuclei grow in a fluidized bed, by causing a liquid material to solidify thereon, the liquid material being introduced into the bed from the bottom upwards with the aid of a feeding device provided with a central ch...	10/28/1986
4568417	Control system for prilling towers An apparatus and method for controlling the moisture content of prilled products which are produced by air drying a spray of the liquid product, comprises a vessel for receiving a flow of air and a flow of the liquid product (10), a supply line for supply...	02/04/1986
4539077	Process for the preparation of urea An improved process for the preparation of urea from carbon dioxide and excess ammonia at elevated temperature and pressure. The urea solution from the urea synthesis zone is heated and stripped at an elevated pressure to decompose a portion of the ammoni...	09/03/1985
4316767	Process for concentrating aqueous urea solutions Disclosed is a process for concentrating aqueous urea solutions in which an aqueous urea solution is allowed to flow as a falling film in countercurrent contact with a stream of hot inert gas to concentrate it to 95-99% by weight and the aqueous urea solu...	02/23/1982
4231839	After-treatment processes and apparatus, especially for urea and ammonium nitrate plants Disclosed are after-treatment processes and apparatus for synthesis plants, particularly urea and ammonium nitrate plants, but applicable also to various other plants in which the synthesis reaction does not go to substantial completion. In such plants pr...	11/04/1980
4219589	Process for urea granulation Urea granules are prepared by spraying an aqueous urea solution having a urea concentration of 70-99.9% by weight on to fluidized urea nuclei in the form of droplets having a mean drop diameter of 20-120 μm at a temperature at which the water is evaporat...	08/26/1980
4069253	Process for the production of water-free molten urea An aqueous urea solution is concentrated to a substantially water-free molten urea by conducting successively a first step of concentrating said aqueous urea solution under the conditions forming a urea slurry and a second step of concentrating said urea ...	01/17/1978
3992372	Processing polycaprolactam extraction liquors A process for processing polycaprolactam extraction liquors by evaporation of water and distillation of the residue in which the evaporation of water is carried out in a plurality of stages and the evaporation energy for the removal of the bulk of the wat...	11/16/1976

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Class 159/47.2 - Involving urea