Trimeric cyanamide joint production method using one step method

Abstract

The invention discloses a normal-pressure one-step melamine co-production method, which belongs to the melamine production method. In this method, the ammonia gas from the ammonia synthesis section is sent directly to the melamine section at a pressure of 0.10-0.15MPa, and is preheated to 350-400°C by steam and molten salt, and then used as the carrier gas ammonia of the fluidized bed; from the liquid urea scrubber The gas that comes out is divided into two branches, one is returned to the crystallizer as cold air, and the other is directly sent to the absorption post of ammonium bicarbonate / soda ash and ammonium chloride to produce ammonium bicarbonate / soda ash and ammonium chloride. It integrates the two-step melamine co-production method under normal pressure and the one-step melamine method, so the quality of melamine products is good, the consumption of raw materials is low, the labor intensity is small, the scale is large, and the investment is low; the investment is 40% lower than that of the one-step melamine method under normal pressure. , power consumption is reduced by 60%; it uses pure ammonia as the carrier gas ammonia, which improves the efficiency of equipment and catalysts by up to 30%; no new tail gas treatment device is needed, and the tail gas is economically and rationally used.

Description

technical field [0001] The invention relates to a one-step melamine method, in particular to a normal-pressure one-step melamine co-production method. Background technique [0002] At present, melamine is generally produced with urea as raw material by high pressure, low pressure or normal pressure methods. The high-pressure method and the low-pressure method have large investment, large amounts of waste water and waste residue, which are contrary to environmental protection requirements, and the total cost is high; due to the low pressure (absolute pressure 0.10-0.15MPa) of the normal-pressure method production process, it is less corrosive and has a long equipment life. The main equipment can be used for at least 15 years. Among them, the two-step production process of the normal pressure method has less investment, but the production cost is high, the labor intensity is high, and the single-set capacity is small; the two-step co-production process...

AI Technical Summary

Problems solved by technology

The high-pressure method and the low-pressure method have large investment, large amounts of waste water and waste residue, which are contrary to environmental protection requirements, and the total cost is high; due to the low pressure (absolute pressure 0.10-0.15MPa) of the normal-pressure method production process, it is less corrosive and has a long equipment life. The main equipment can be used for at least 15 years

Among them, the two-step production process of the normal pressure method has less investment, but the production cost is high, the labor intensity is high, and the single-set capacity is small; the two-step co-production process of the normal pressure method still cannot get rid of the low degree of automation of the original process and the labor intensity Large size, bad working environment, small single-set capacity, high consumption of raw materials and energy, poor tail gas purity, etc.; although the atmospheric pressure one-step method has got rid of some disadvantages of the two-step method, it shows low labor intensity, good product quality, and large single-set capacity , no waste residue and waste water discharge, but the production process has a large investment, high power consumption, and high cost, which is basically equivalent to the two-step method

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