Energy-saving process for producing melamine

Abstract

The invention relates to an energy-saving process for producing melamine, comprising the following steps: using urea as the raw material, and producing melamine, ammonia and carbon dioxide in a reactor under the catalytic function of a catalyst at 350-420 degrees centigrade and a pressure of 0-1.5 MPa through reaction, wherein material gas from the reactor enters a hot-gas cooler, and the cooled hot technological gas enters a filter to be filtered, and the filtered technological gas containing melamine enters a crystallizer, and the melamine after crystallization enters a cyclone separator, and the separated solid triamine is sent to a storage bin to be packaged, and the gas coming out from the cyclone separator enters a heat exchanger; cooling the gas containing ammonia and carbon dioxide at about 200-220 degrees centigrade by water to about 30-145 degrees centigrade, and purifying the technological gas in an urine liquid washing tower; separating urine liquid fog drops carried in the purified gas by a separator, wherein the gas after separation is divided into three ways: one way gas is compressed into the reactor by the compressing machine, and one way gas enters the crystallizer by a cool air fan through pressure boosting to be used as cool air, and one way is a tail gas exhaust system for other purposes. The process disclosed by the invention has characteristics of compact equipment, simple technology, less energy consumption, cost saving and so on.

Description

technical field [0001] The invention relates to an energy-saving melamine production process. Background technique [0002] The current production process of melamine uses liquid urea as the raw material. In the fluidized bed reactor, it reacts at 350-420°C and 0-1.5MPa pressure to form melamine, ammonia and carbon dioxide. The material gas from the reactor enters the hot gas. Cooler, gasification and cooling, so that the high boiling point by-products are crystallized as solids, the cooled process material gas enters the hot gas filter to filter the solid impurities in the gas, and the filtered gas enters the crystallizer and comes from the liquid urine washing system The process cold air is reverse contact heat exchange, melamine is precipitated from the process material gas in the form of solid, and then the gas containing melamine solid is separated by the cyclone separator and sent to the packaging system. The gas from the cyclone separator is pressurized by the fan an...

AI Technical Summary

Problems solved by technology

The disadvantage of this process is that the air-conditioning fan pressurizes the high-temperature gas, which requires a large fan power and high energy consumption; the temperature difference between the liquid and urine in the liquid and urine washing tower changes greatly, and it is easy to block or form walls, block the liquid and urine nozzle, and affect the device. run cycle

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