Casale Sa

Urea Casale Sa

Paolo Bertini

Leonardo Marrone

Matteo Fumagalli

Andrea Scotto

Serena Gabbiadini

Alberto Benedetti

Gabriele Di Carlo

A process for purifying a urea-containing aqueous stream, such as the aqueous stream from the recovery section of a urea plant, comprising a step of removing biuret from the urea-containing stream by reverse osmosis in one or more reverse osmosis stages.

Process for producing low-biuret urea

Process for the preparation of urea granules comprising the steps of obtaining an aqueous urea solution from one or more synthesis and recovery steps wherein ammonia and carbon dioxide are reacted together, subjecting the aqueous urea solution to an evaporation step wherein water is removed to obtain a urea melt (), processing and treating said urea melt in a granulation step () and optionally in a cooling section () to obtain solid urea granules (); the process further comprises a scrubbing step () of granulation offgas and an atmospheric evaporation step () to recover a urea solution () and a water-saturated air stream (): the water-saturated air stream is fed back to the scrubbing section () without condensation, and the recovered urea solution is conveyed to the granulation step ().

Urea production process and plant

A process for synthesis of urea from ammonia and carbon dioxide wherein: the urea synthesis is performed with a stripping process in a synthesis loop including at least a reactor (), a stripper () and a condenser (); the reactor effluent is treated in the stripper to remove unreacted ammonia and carbon dioxide; the urea solution () from the stripper is sent to a low-pressure recovery section (); the stripper vapours are split into a first portion () directed to the reactor and a second portion () sent to the condenser; the condenser () is a shell-and-tube kettle condenser where condensation of stripper vapours is performed in the tube side (); a carbamate-containing effluent () from the condenser is returned to the reactor.

Process and plant for the synthesis of urea

A process for synthesis of urea from ammonia and carbon dioxide comprising the synthesis of urea in parallel in a first urea reactor () at a first urea synthesis pressure and in a second urea reactor () at a second and lower urea synthesis pressure; a stripping step of the reaction effluent of the first reactor, which is performed in a stripper () operating at a stripping pressure lower than the first urea synthesis pressure; the reaction effluent () of the second reactor () and the stripper liquid effluent () are sent to a recovery section () where a carbamate-containing recycle solution () is produced, and said recycle solution () is sent partly to said first reactor and partly to said second reactor.

Process for the synthesis of urea

Plant for the synthesis of urea comprising: a synthesis section (), wherein ammonia () and carbon dioxide () react to give an aqueous solution () containing urea and ammonium carbamate; at least one recovery section fed with said depressurized aqueous solution and in a two-phase state, said recovery section comprising a separator () which processes said two-phase solution; a pre-decomposer (), a decomposer () and a condenser (), wherein the gaseous streams obtained in the separator and in the decomposer are condensed in said condenser of the recovery section.

A process for the finishing of urea comprising: (a) removing water from an aqueous urea solution in a first evaporation and condensation section, obtaining a urea melt; (b) subjecting said urea melt to a finishing treatment comprising granulation and resulting in solid urea and air contaminated with urea dust and ammonia; (c) subjecting said contaminated air to acid scrubbing, producing an aqueous solution comprising urea and ammonium salts; (d) subjecting at least part of said aqueous solution to evaporation in a second evaporation section, obtaining a liquid stream comprising urea and ammonium salts and a gaseous stream; (e) condensing said gaseous stream in a second condensation section, obtaining a recycle aqueous stream; (f) using at least a part of said recycle aqueous stream for the scrubbing of contaminated air; (g) converting at least a portion of said liquid stream comprising urea and ammonium salts into solid particles, and (h) using said solid particles as seeds for the granulation; a corresponding urea plant and method of revamping a urea plant are also disclosed.

Urea finishing process with acid scrubbing

An integrated process for the synthesis of urea and melamine, wherein: urea is synthesized with a stripping process in a high-pressure synthesis loop comprising a reactor, a stripper and a carbamate condenser, and the urea solution leaving said stripper is sent to a recovery section to produce a concentrated urea product and a recovered carbamate solution; at least part of said urea product is converted to melamine, and the off-gas from the synthesis of melamine are recycled to the urea synthesis by mixing with the gas phase from the stripper and with said recovered carbamate solution, thus forming a mixed flow which is then condensed in said carbamate condenser, and the condensate is eventually directed to the reactor.

Process and plant for the synthesis of urea and melamine

A method for revamping a self-stripping urea plant comprising the installation of a new CO2-stripping synthesis section (), wherein at least part of the aqueous urea solution () leaving said new section () is directed to the existing low pressure recovery section () of the self-stripping plant, by-passing the existing self-stripping high-pressure section () and medium pressure treatment section ().

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Lugano, Switzerland

Paolo Bertini