Integrated production of urea and melamine
AssigneeStamicarbon B.V.
InventorJohannes Henricus MENNEN
Life of this patent
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Abstract
Disclosed is a process for the integrated production of urea and melamine. A urea production zone produces a urea synthesis stream comprising urea, water and ammonium carbamate. This stream is subjected to processing, preferably involving stripping, so as to separate an aqueous urea stream from residual dissociated carbamate vapor comprising ammonia, carbon dioxide, and water. The urea is fed to a melamine synthesis zone and subjected to melamine forming conditions so as to form melamine and off-gas comprising carbon dioxide and ammonia. The dissociated carbamate vapor and the melamine off-gas are subjected to combined condensation so as to form a dilute melamine off-gas condensate.
Claims10
A process for the integrated production of urea and melamine, the process comprising subjecting carbon dioxide and ammonia to urea forming conditions in a urea production zone, so as to form a urea synthesis stream comprising urea, water and ammonium carbamate;
- subjecting the urea synthesis stream to processing so as to obtain an aqueous urea stream and a vapor comprising ammonia, carbon dioxide, and water;
- feeding urea to a melamine production zone;
- subjecting the urea fed to the melamine production zone to melamine forming conditions so as to form melamine and melamine off-gas comprising carbon dioxide and ammonia;
- feeding the off-gas to the urea production zone;
- subjecting the vapor and the melamine off-gas to condensation;
- forming a combined stream of the condensate of the vapor and the condensate of the off-gas, so as to provide a dilute melamine off-gas condensate, and using said dilute melamine off-gas condensate as a fluid in indirect heat-exchange.
A method for reducing the energy consumption of a urea production zone of a pre-existing facility for the integrated production of urea and melamine, said facility comprising a urea production zone and a melamine production zone;
- the urea production zone comprising a urea synthesis section and a carbamate recirculation section comprising a liquid/gas separation section;
- the melamine production zone comprising a melamine synthesis section and an off-gas separation section, the method comprising adding a concentrator to the urea production zone, said concentrator comprising an evaporation chamber for liquid to be heated and evaporated, said evaporation chamber comprising a gas outlet for evaporated liquid and being in heat-exchanging communication with a chamber for indirect heat exchange;
- providing a transport line for liquid feed from the liquid/gas separation section of the urea plant to said evaporation chamber;
- providing a gas flow-line from the liquid/gas separation section of the urea plant to a condensation system, said condensation system comprising a liquid outlet in fluid communication with the chamber for indirect heat exchange;
- and, providing a gas flow-line from the off-gas separation section of the melamine production zone to the condensation system.
A method of increasing the plant capacity of the melamine production zone of a pre-existing facility for the integrated production of urea and melamine, said facility comprising a urea production zone and a melamine production zone;
- the urea production zone comprising a urea synthesis section and a carbamate recirculation section comprising a liquid/gas separation section;
- the melamine production zone comprising a melamine synthesis section and an off-gas separation section, the method comprising expanding the melamine synthesis capacity of the melamine synthesis section;
- adding a concentrator to the urea production zone, said concentrator comprising an evaporation chamber for liquid to be heated and evaporated, said evaporation chamber comprising a gas outlet for evaporated liquid and being in heat-exchanging communication with a chamber for indirect heat exchange;
- providing a transport line for liquid feed from the liquid/gas separation section of the urea plant to said evaporation chamber;
- providing a gas flow-line from the liquid/gas separation section of the urea plant to a condensation system, said condensation system comprising a liquid outlet in fluid communication with the chamber for indirect heat exchange;
- and, providing a gas flow-line from the off-gas separation section of the melamine production zone to the condensation system.
Dependencies are inferred from the claim text.