Apparatus for joint production of methanol and synthetic ammonia by using exhaust gas from methanol synthesis

Abstract

The invention discloses an apparatus for joint production of methanol and synthetic ammonia by using exhaust gas from methanol synthesis. The apparatus comprises a carbon dioxide adsorption tower, a methanol synthesis tower, a methanol cooler, a methanol separator, a methane synthesis tower, an amonia synthesis tower, an alkaline air cooling apparatus, an alkaline air separation tower and a flash evaporation tank. Devices of the methanol synthesis tower, the methanol cooler, the methanol separator, the methane synthesis tower, the amonia synthesis tower, the alkaline air cooling apparatus, the alkaline air separation tower and the flash evaporation tank are connected with each other through pipes. A liquid ammonia outlet of the flash evaporation tank is communicated with a liquid ammonia collector, and a gas outlet of the flash evaporation tank is communicated with an ammonia recovery system. According to the present invention, a industry chain of hard coke-coke oven gas-methanol producing-synthetic ammonia producing is formed and a cyclic economy route with full resource utilizing is provided, such that population problems from coking enterprises are fundamentally solved, the exhaust gas is transformed into the liquid ammonia so as to effectively raise added values of products and improve economic benefits of the enterprises.

Description

technical field [0001] The invention relates to a device for jointly producing methanol and synthetic ammonia by using methanol purge gas. Background technique [0002] my country's coke production is very large. In 2010, my country's coke production reached 250 million tons. China's coke production ranks first in the world for consecutive years, accounting for 46% of the world's total coke production. China's coke is mainly used in the domestic steel industry. The coking industry, which has developed rapidly with the huge demand for coke in the iron and steel industry, has not been rationally utilized by a large amount of by-product coke oven gas while coke production has increased significantly, resulting in a sharp deterioration of the environment in coke production areas. Many Independent coking enterprises with a single coking process "only coke but not melt", burn and release a large amount of coke oven gas by lighting sky lanterns, which not only seriously pollutes t...

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Problems solved by technology

Since the hydrogen element in coke oven gas is generally more than 70%, and the carbon element is less than 15%, and the chemical reaction hydrogen to carbon ratio of methanol synthesis is 2:1, so the carbon element is insufficient during the methanol synthesis reaction, and the coal-to-gas supplement Carbon is unrealistic, so most domestic coke oven gas to methanol processes do not have carbon replenishment devices, resulting in a high hydrogen-to-carbon ratio in the synthesis gas. Excessive hydrogen in the synthesis reaction will increase the amount of circulating gas in the methanol synthesis loop and increase the synthesis cycle. The power consumption of the compressor and the discharge of the blowdown gas make the clean hydrogen produced through multiple processes such as purification and conversion enter the fuel system as the blowdown gas and burn it, which wastes resources and increases production consumption.

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