Process for coproducing melamine and ammonium sulfate

Abstract

The invention relates to a process for coproducing melamine and ammonium sulfate. The process comprises the following steps of: melting urea serving as a raw material in a urea fusion tank to form liquid urea, conveying the liquid urea into a reactor by a liquid urea washing tower, filtering reacted gas to remove impurities, condensing melamine to form a solid by a crystallizer, and conveying the solid into a cyclone separator for a finished product along with the mixed gas, discharging, cooling and packaging to obtain the melamine; and pressurizing tail gas exhausted from the top of the cyclone separator by a cold air fan to enter the liquid urea washing tower, and dividing the tail gas into three paths, wherein the first path of tail gas is pressurized by a gas carrying compressor, is used as fluidized bed carrier gas and enters the reactor; a second path of tail gas returns to the crystallizer circularly to be used as quenching gas; the third path of tail gas is separated from the gas carrying compressor, enters an ammonium sulfate saturator and reacts with sulfuric acid to generate an ammonium sulfate crystal, and the ammonium sulfate crystal is separated by a centrifugal machine to obtain an ammonium sulfate finished product; and an ammonium sulfate mother solution returns to a mother solution circulating tank to be recycled. The ammonium sulfate is large in crystalline particles, and the process is simple, easy to operate and environment-friendly, and has an obvious economic benefit.

Description

technical field [0001] The invention relates to a process for preparing ammonium sulfate, in particular to a process for co-producing ammonium sulfate with melamine. Background technique [0002] The scientific name of melamine is 2,4,6-triamino-1,3,5-triazine, also known as melamine or cyanuramide, and its English name is Melamine. It is an important organic chemical intermediate product, mainly used in the production of melamine-formaldehyde resin ( MF resin). At present, melamine is produced with urea as the raw material in the world. The industry is used to dividing the urea process into high-pressure method and low-pressure method, and most of its technological process adopts gas-phase quenching method. However, no matter the high-pressure method or the low-pressure method, the whole process includes three processes: reaction synthesis, separation and purification, and tail gas treatment. Among them, tail gas treatment is the focus of current research, and how to make...

AI Technical Summary

Problems solved by technology

The existing ammonium sulfate production technology is mainly the production of ammonium sulfate from coke oven gas clean ammonia, the production of ammonium sulfate from ammonia flue gas desulfurization, and the production of ammonium sulfate from waste ammonia water. However, the traditional ammonia gas production of ammonium sulfate has a large amount of steam and production costs. high

At the same time, the steam entrains ammonia gas and acid mist, causing serious environmental pollution

Images