Associated melamine from carbon ammonium through technique of two-step method under normal pressure

Abstract

This invention discloses a two-step process for producing melamine from urea under normal pressure. The method comprises: (1) blowing urea with ammonia into a reactor, mixing with ammonia from a circulation machine, preheating and blowing the catalyst from the bottom of the reactor to fluidize; (2) discharging the reactant from the top of the reactor, removing the catalyst dust by an outer filter, introducing into a collector, cooling naturally and condensing to obtain melamine; (3) purifying the circulation gas from the collector with an absorbing column to absorb carbon dioxide; (4) reacting the mother liquor obtained in step 3 and carbon dioxide obtained by the decarbonization of ammonium bicarbonate to obtain ammonium carbonate; (5) cooling the purified circulation gas, introducing into the circulation machine, concentrating, and passing into the reactor. Compared with present techniques, the method has such advantages as low raw material cost, high profit, easy control, simple process and reliable operation.

Description

technical field [0001] The invention belongs to the technical field of preparing melamine from urea, and in particular relates to a two-step normal-pressure ammonium bicarbonate co-production process for melamine. Background technique [0002] Melamine, also known as melamine (melamine), is an important organic chemical intermediate product, and its main industrial use is to polycondensate with formaldehyde to produce melamine-formaldehyde resin. The production method of melamine is divided into dicyandiamide method and urea method according to raw materials. The raw material of the dicyandiamide method starts with calcium carbide, which consumes a large amount of electric energy, and the source of raw materials is difficult. This method has now been eliminated. [0003] At present, urea is used as raw material in domestic melamine production, and most of its technological process adopts atmospheric pressure dry capture and refining method. The process is generally divided...

AI Technical Summary

Problems solved by technology

The disadvantage is that the concentrated ammonia water generated after absorption is circulated into the carbonization tower, and the ammonia gas coming out of the carbonization tower still needs to be absorbed by the purification tower, and the operation process is relatively complicated.

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