Patent ID: 8431696
Filing Date: 2013-04-30
Classification: C07D

Abstract:
1. A process for the continuous production of melamine, wherein in a fluidized-bed reactor, in the presence of a catalyst, by supplying heat and by adding ammonia, the liquid urea used as starting material is converted into a process gas, chiefly consisting of melamine, ammonia, carbon dioxide, the intermediate product isocyanic acid and by-products, and wherein this process gas, after the by-products and the melamine have been separated therefrom, is passed into a scrubber in which it is washed with liquid urea and liberated from the isocyanic acid content, wherein the process gas, after leaving the scrubber, in part is used as fluidizing gas in the fluidized-bed reactor, in part is used as cooling gas in the crystallizer, and in part is discharged from the process gas circuit, wherein in flow direction before the scrubber a partial stream is branched off from the process gas stream, guided past the scrubber, and in flow direction before the fluidized-bed reactor introduced into the process gas stream serving for fluidization and treated in the scrubber.