Process and system for preparing ethylene from powdered coal by two-stage calcium carbide furnace

Abstract

The invention relates to a process and a system for preparing ethylene from powdered coal by a two-stage calcium carbide furnace. The process includes (1) two-stage calcium carbide furnace production; (2) carbon monoxide transformation and decarburization for hydrogen production; (3) acetylene generation; (4) acetylene hydrogenation reaction; and (5) cryogenic separation. According to the invention, the upper and lower two-stage calcium carbide furnace is adopted, the pyrolysis process and the calcium carbide production process are combined, the continuous calcium carbide production process and the effective utilization of heat energy are realized, so that the energy consumption of calcium carbide production is effectively reduced; and middle and low order pulverized coal with low costs is adopted as carbon materials, the costs are reduce, the raw material surface area is increased, the reactivity is increased, the calcium carbide smelting temperature is reduced, and the energy consumption is effectively reduced. Tar and pyrolysis gas by-products with high added values are obtained in the pyrolysis process, so that the overall economy of the process is improved, and in addition, the process adopts a liquid solvent to absorb acetylene, avoids the acetylene polymerization explosion hazard, and realizes high pressure reaction, so as to improve the production capacity of the device.

Description

Technical field [0001] The invention relates to a process and system for producing ethylene from pulverized coal in a two-stage calcium carbide furnace and belongs to the technical field of coal chemical industry. Background technique [0002] Ethylene is a major raw material in the petrochemical industry. The current preparation process is mainly the cracking of naphtha to olefins and coal to olefins. In 2015, the total domestic ethylene production capacity will reach about 22 million t / a. In 2020, the domestic ethylene production capacity will further increase to 32.5 million t / a. It is estimated that the domestic ethylene consumption will be 48 million tons by 2020. The demand is greater than the production capacity, which is important for oil reserves. my country, which is not rich, poses a serious strategic threat. Therefore, seeking another new source and process to prepare bulk basic organic chemical raw material-ethylene, and replacing petroleum as a raw material in the f...

AI Technical Summary

Problems solved by technology

However, this process has a long technical process, complex process, large investment, high carbon emissions, especially the large demand for water, which makes it impossible to carry out in water-scarce areas.

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