| 摘要 |
The invention relates to a process for the preparation of melamine from urea comprising the steps of: a) introducing urea melt and hot ammonia gas into a melamine reactor having a pressure within the range 50-150 bar and a temperature within the range 360-470° C., to obtain a melamine melt and off-gases; b) separating said off-gases from said melamine melt; c) introducing said melamine melt and ammonia gas into an evaporator having a pressure within the range 1-15 bar and a temperature within the range 290-520° C., to obtain a melamine-containing gas mixture; and d) introducing said melamine-containing gas mixture into a cooler having a pressure within the range 1-15 bar and a temperature within the range 0-250° C., to convert the gaseous melamine to solid high purity melamine.
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