Energy-saving technology for producing melamine by one-step method

Abstract

The invention discloses an energy-saving technology for producing melamine by a one-step method, mainly comprising the following steps: supplying heat to a fluidized bed reactor by a superconducting liquid heating furnace or a heat pipe heating furnace; cooling produced gas-state melamine and a high-temperature mixed gas of ammonia and carbon dioxide by a heat pipe exchanger; and then filtering, crystallizing and separating to obtain a finished product solid melamine, wherein the rest mixed gas of the ammonia and the carbon dioxide can be circularly used for supplying a working gas for a system after being purified and can also enter a synthesis ammonia soda ash device or a synthesis ammonia ammonium carbonate device or a synthesis ammonia nitramine device to be used for supplying a raw material for the system. Compared with the traditional one-step method, the energy-saving technology can reduce the fuel consumption by 40 percent and the electric power consumption by 30 percent.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to an energy-saving production process of melamine. Background technique [0002] At present, the production process of melamine includes normal pressure one-step method and normal pressure two-step method, and low-pressure one-step method and high-pressure one-step method. Relevant to the present invention are atmospheric pressure one-step process and low pressure one-step process. [0003] The main production process of the atmospheric pressure one-step method is to use the salt melting furnace as the heat source and urea as the raw material. The liquid urea reacts endothermicly under the action of the catalyst in the fluidized bed reactor to form a mixed gas of melamine, ammonia and carbon dioxide. The mixed gas After cooling, filtering, crystallization and separation, the finished melamine is obtained; the separated ammonia and carbon dioxide mixed gas is cooled and washed by t...

AI Technical Summary

Problems solved by technology

[0011] 1. The thermal efficiency of the molten salt heating system is low, the heat loss is large, the fuel consumption is high, and the waste heat cannot be recycled by the system, resulting in a large waste of heat; in addition, the molten salt needs to rely on power cycle, which consumes a lot of energy

[0012] 2. The liquid urine cooling and washing tower is made of stainless steel, which requires a large investment, takes up a large amount of production space, and has high operating costs such as electricity; and the liquid urine will not only cause a large amount of power consumption during the long-term forced circulation process, but also cause partial shrinkage. Urea, this part of biuret will not be converted into triamine during the reaction process, which increases the consumption of urea;

[0013] 3. The air-conditioning fan circulates on the total air path, the circulating air volume is large, and the inlet temperature is high, which makes the fan expensive and power consumption high

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