Urea Casale Sa

Casale Sa

Ammonia Casale Sa

Ureaecasale S.a.

Federico Zardi

Giorgio Pagani

Paolo Brunengo

Paolo Silva

Ermanno Filippi

Andrea Scotto

Domenico Romiti

Paolo Sticchi

Enrico Rizzi

Mirco Tarozzo

Raffaele Ostuni

Marco Badano

Sergio Debernardi

The present invention regards a process for the production of an aqueous solution comprising urea for use in the removal of nitrogen oxides from combustion gas or fumes, the process being characterized in that it comprises the steps of: &#x2014;subjecting at least a part of a urea-concentrated aqueous solution comprising residual free ammonia, obtained directly from or downstream of a recovery section of a plant for the production of urea, to washing with carbon dioxide, so obtaining a first vapor phase comprising carbon dioxide and optionally ammonia and a urea-concentrated aqueous solution comprising carbamate and essentially lacking in free ammonia, and &#x2014;diluting said urea-concentrated aqueous solution comprising carbamate and essentially lacking in free ammonia with water until the desired concentration of urea in aqueous solution is reached.

Process and plant for the production of an aqueous solution comprising urea

In an integrated process for urea and melamine production, urea is produced in a urea plant () comprising a high pressure urea synthesis section () from which an aqueous solution comprising urea, ammonium carbamate and ammonia is obtained and a urea recovery section () operating at low pressure, and melamine is produced in a melamine plant () wherein off-gases resulting as by-products of the melamine synthesis are discharged from said plant at a medium pressure and recycled to the high-pressure urea synthesis section ().

Integrated process for urea and melamine production

A process for ammonia-urea production where: liquid ammonia produced in an ammonia section is fed to a urea section directly at the ammonia synthesis pressure, and where the liquid ammonia is purified at high pressure with the steps of: cooling the liquid ammonia () obtaining a cooled liquid ammonia stream (), separating a gaseous fraction () comprising hydrogen and nitrogen from said cooled liquid ammonia, obtaining purified liquid ammonia () at a high pressure, and reheating said purified liquid ammonia () after separation of said gaseous fraction, obtaining a reheated purified ammonia () having a temperature suitable for feeding to the urea synthesis process. The application also deals with an ammonia-urea plant comprising an ammonia cooler, a liquid-gas separator and an ammonia re-heater and with a method for revamping existing ammonia-urea plants.

Process and plant for ammonia-urea production

A method for regulation of an ammonia plant where a purge gas () containing inerts is extracted from ammonia synthesis loop (SL), and where the ammonia plant is operated at a partial load by keeping the ammonia synthesis loop at a nominal high pressure, and reducing the purge rate in order to increase concentration of inerts in the ammonia synthesis loop and avoid overheating of the ammonia reactor; preferably a water electrolysis section (WE) produces a hydrogen feed () and an air separator produces a nitrogen feed (); hydrogen and nitrogen are mixed to form a make up gas () which is reacted at a high-pressure in said ammonia synthesis loop (SL).

Method for load regulation of an ammonia plant

Plant for urea production from ammonia and carbon dioxide having a so-called high-pressure section which comprises a synthesis reactor and a condensation unit () positioned inside the reactor, all substantially operating at the same pressure.

Plant for urea production

A process for producing urea is disclosed, wherein liquid ammonia and carbon dioxide are reacted in a high-pressure synthesis section (), and at least part of the carbon dioxide is fed to said synthesis section () in liquid phase. A plant operating according to said process and a method for modernizing existing plants accordingly are also disclosed.

Process and plant for urea production

A method for revamping a conventional self-stripping urea plant is disclosed, where a minor portion () of the carbon dioxide feed is fed to the stripper () and used as a stripping agent. In further embodiments, another carbamate condenser is installed, or the conventional horizontal shell-and-tube carbamate condenser () is replaced with a vertical submerged unit.

Method for the modernization of a urea production plant

A process and a related plant layout for producing urea are disclosed, wherein the high-pressure loop () comprises a synthesis reactor (), a thermal stripper (), a condenser (), and an adiabatic COstripper () disposed upstream said thermal stripper, separating a vapour phase () containing ammonia from the urea solution () discharged from the reactor, and recycling said vapour phase to the reactor. The adiabatic stripper () can be incorporated in a reactor () having a top reaction zone and a bottom adiabatic stripping zone. A revamping method for a conventional urea plant in accordance with the inventive process is also disclosed.

High-pressure loop in a process for synthesis of urea

A process for urea production from ammonia and carbon dioxide, in which part of the aqueous solution comprising urea, ammonium carbamate and ammonia obtained in a urea synthesis section is subjected to dissociation in a treatment section operating at a predetermined medium pressure for the recovery of the ammonium carbamate and of the ammonia contained in it, comprises the steps of subjecting the urea aqueous solution resulting from the aforementioned dissociation step to decomposition in a low pressure urea recovery section and of using at least a part of the condensed steam, obtained by indirect thermal exchange with a second part of said aqueous solution comprising urea, ammonium carbmate and ammonia in a high-pressure stripping unit, as a heating fluid for the dissociation of the first part of the aqueous solution comprising urea, ammonium carbmate and ammonia in the medium-pressure treatment section.

Process for urea production and related 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 unit for substantially condensing at least a portion of a flow comprising ammonia and carbon dioxide in vapor phase leaving the stripping unit; a second stripping unit; means for feeding a first portion of a reaction mixture flow comprising urea, carbamate and free ammonia in aqueous solution leaving the reactor to the first stripping unit; means for feeding a second portion of the reaction mixture flow leaving the reactor to the second stripping unit; and means for feeding at least a portion of a flow comprising ammonia and carbon dioxide in vapor phase leaving the second stripping unit directly to the synthesis reactor. A de-bottlenecking of the high-pressure section downstream of the synthesis reactor may be achieved, improving production capacity.

Method for modernizing a urea production plant

A process for urea production from ammonia and carbon dioxide, in which part of the aqueous solution comprising urea, ammonium carbamate and ammonia obtained in a urea synthesis section is subjected to dissociation in a treatment section operating at a predetermined medium pressure for the recovery of the ammonium carbamate and of the ammonia contained in it, comprises the step of subjecting the urea aqueous solution resulting from the aforementioned dissociation step to decomposition in a low pressure urea recovery section.

A carbamate condensation unit of the submerged type for synthesis urea production plants comprising a tube bundle for the condensation of gaseous compounds, is distinguished in that it further comprises a duct, structurally independent from the tube bundle, for the circulation of part of the condensed gaseous compounds inside the condensation unit.

Carbamate condensation unit

In an integrated process for urea and melamine production, 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, and melamine is produced in a melamine plant () wherein off-gases resulting as byproducts of the melamine synthesis are discharged therefrom at a pressure of at least 2 bar and recycled to the high pressure urea synthesis section ().

A process for the separation and recovery of carbon dioxide from waste gases produced by combustible oxidation is described comprising the steps of feeding a flow of waste gas to a gas semipermeable material, separating a gaseous flow comprising high concentrated carbon dioxide from said flow of waste gas through the gas semipermeable material, and employing at least a portion of the gaseous flow comprising high concentrated carbon dioxide as feed raw material in an industrial production plant and/or stockpiling at least a portion of the gaseous flow comprising carbon dioxide.

Process for the preparation and recovery of carbon dioxide from waste gas or fumes produced by combustible oxidation

A process for urea production comprises the steps of:&#x2014;performing a reaction between ammonia and carbon dioxide in a reaction space to obtain a reaction mixture comprising urea, carbamate and free ammonia in aqueous solution,&#x2014;subjecting said mixture to a stripping treatment with carbon dioxide feed as a stripping agent to obtain a first flow comprising ammonia and carbon dioxide in vapor phase and a flow comprising urea and residual carbamate in aqueous solution,&#x2014;feeding said flow comprising urea and residual carbamate in aqueoue solution to a urea recovery section,&#x2014;separating in said recovery section said residual carbamate from the urea to obtain a first flow of carbamate in aqueous solution.

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Breganzona, Switzerland

Federico Zardi