Patent ID: 6815545
Filing Date: 2004-11-09
Classification: B01J,C07D

Abstract:
A process for the production of melamine by pyrolysis of urea in a high-pressure reactor having a vertical central pipe with formation of a melamine melt, comprising:mixing melamine melt circulating in the reactor in the lower region of the reactor with a urea melt introduced into the reactor from below and optionally with introduced NH3 to form a reaction mixture comprising melamine, NH3, CO2 and optionally reaction intermediates, wherein the reaction mixture flows upwards from below in the central pipe and emerges from the upper part of the central pipe; separating melamine and off-gas at the top of the reactor above the central pipe, wherein part of the melamine emerging above from the central pipe flows downwards in an annular space between the central pipe and reactor wall and the remainder is expelled for further work-up; and continuously expelling the off-gases at the top of the reactor.