METHOD FOR PREPARING MELAMINE

摘要

Method for preparing melamine from urea via a high-pressure process in which solid melamine is obtained by transferring the melamine melt coming from the reactor to an expansion vessel where the melamine melt is cooled by incorporated ammonia. The melamine melt coming from the reactor is fed into a gas/liquid separator where additional ammonia is added to remove oxygen-containing compounds. The purified melamine melt is then fed into a vaporizer where the melamine melt is vaporized. The melamine vapour, along with ammonia gas, is then fed into a quench vessel where the melamine vapour is cooled and solidified by mixing with a cooling fluid such as liquid ammonia. The melamine vapour is thereby directly converted into melamine powder after which the melamine powder is cooled further and the ammonia pressure is released.