The disclosure pertains to a process for the production of urea and melamine, wherein off-has from a high pressure melamine plant is combined with a urea liquid obtained from flashing of a urea synthesis solution. Also disclosed is a system for the combined production, and the modification of an existing plant or system.

The disclosure pertains to a process for the production of urea and melamine, wherein off-has from a high pressure melamine plant is combined with a urea liquid obtained from flashing of a urea synthesis solution. Also disclosed is a system for the combined production, and the modification of an existing plant or system.

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.

A process for the synthesis of urea and melamine, wherein urea synthesized in a urea plant is used to produce melamine in a melamine plant connected to the urea plant, according to a high-pressure non-catalytic melamine synthesis process, and offgas (16) liberated during the synthesis of melamine are returned to the urea plant after offgas processing (8) which includes a condensation and a urea formation step so that a urea-containing recycle stream (19) is returned to the synthesis section of the urea plant.

A process for the synthesis of urea and melamine, wherein urea synthesized in a urea plant is used to produce melamine in a melamine plant connected to the urea plant, according to a high-pressure non-catalytic melamine synthesis process, and offgas (16) liberated during the synthesis of melamine are returned to the urea plant after offgas processing (8) which includes a condensation and a urea formation step so that a urea-containing recycle stream (19) is returned to the synthesis section of the urea plant.

Embodiments pertain to a urea plant and to the operation of a urea plant in a reduced load mode. In embodiments, two evaporators in parallel are used, connected to a finishing section respectively to a melamine plant.

Embodiments pertain to a urea plant and to the operation of a urea plant in a reduced load mode. In embodiments, two evaporators in parallel are used, connected to a finishing section respectively to a melamine plant.

The disclosure pertains to urea production with, in series, an MP carbamate condenser for condensing at least urea synthesis section off-gas, gas/liquid separation giving a gas stream and a liquid stream, and a second carbamate condenser receiving off-gas from melamine production and said liquid stream.

The disclosure pertains to urea production with, in series, an MP carbamate condenser for condensing at least urea synthesis section off-gas, gas/liquid separation giving a gas stream and a liquid stream, and a second carbamate condenser receiving off-gas from melamine production and said liquid stream.