Reactor for the synthesis of melamine from urea, in accordance with the high-pressure non-catalytic process, comprising: a vertical reactor body (1), at least one inlet (2) for the urea melt, a set of heating elements (3), and a central duct (7), said set of heating elements (3) being arranged inside said central duct.

Disclosed is an integrated process for the production of urea and melamine, as well as a system for carrying out the process. The invention thereby pertains to an integrated process of the type wherein off-gas obtained from the production of melamine is entered into the process for the production of melamine, by condensation in the presence of water. A typical embodiment thereof is the condensation in the presence of an aqueous carbamate solution obtained from urea recovery. In accordance with the invention, said condensation takes place at a substantially lower pressure than the pressure at which the melamine off-gas is obtained. To this end, the pressure of the off-gas is reduced typically by 2-10 bar. In connection herewith, the system of the invention comprises a pressure reducing unit downstream of an outlet for the melamine off-gas, and upstream of a section for the condensation of the off-gas. The invention also includes a method for the modernization of an integrated system for the production of melamine and urea. This is accomplished by adding the aforementioned pressure reducing unit to a pre-existing system.

A reactor and associated process for the high-pressure synthesis of melamine from urea, comprising a primary step of conversion of the urea into crude melamine inside a first chamber delimited by a shell inside a reactor body and a secondary step of stripping said crude melamine melt inside a second reaction chamber, which is coaxial with and situated outside said first chamber, inside the same reactor body.

A reactor and associated process for the high-pressure synthesis of melamine from urea, comprising a primary step of conversion of the urea into crude melamine inside a first chamber delimited by a shell inside a reactor body and a secondary step of stripping said crude melamine melt inside a second reaction chamber, which is coaxial with and situated outside said first chamber, inside the same reactor body.

The disclosure pertains to a coupled plant process for the production of urea and melamine, with a urea synthesis section with HP CO.sub.2 stripping, and with a part of the CO.sub.2 feed supplied to a recovery section.

The disclosure pertains to a coupled plant process for the production of urea and melamine, with a urea synthesis section with HP CO.sub.2 stripping, and with a part of the CO.sub.2 feed supplied to a recovery section.

Reactor for the synthesis of melamine from urea, in accordance with the high-pressure non-catalytic process, comprising: a vertical reactor body (1), at least one inlet (2) for the urea melt, a set of heating elements (3), and a central duct (7), said set of heating elements (3) being arranged inside said central duct.

Reactor for the synthesis of melamine from urea, in accordance with the high-pressure non-catalytic process, comprising: a vertical reactor body (1), at least one inlet (2) for the urea melt, a set of heating elements (3), and a central duct (7), said set of heating elements (3) being arranged inside said central duct.

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.

A reactor and associated process for the high-pressure synthesis of melamine from urea, comprising a primary step of conversion of the urea into crude melamine inside a first chamber delimited by a shell inside a reactor body and a secondary step of stripping said crude melamine melt inside a second reaction chamber, which is coaxial with and situated outside said first chamber, inside the same reactor body.