System for producing natural gas by electrolytic hydrogen production and gas synthesis from coal

Abstract

The invention relates to a system for producing natural gas by electrolytic hydrogen production and gas synthesis from coal. The system comprises a coal preparation unit, wherein the coal preparation unit is connected with a gasification furnace, a crude coal gas outlet of the gasification furnace is connected with an inlet of a first absorption tower, a main circuit of a first absorption tower outlet is connected with a low temperature methanol washing unit through a conversion unit, an auxiliary circuit of the first absorption tower outlet is connected with a power plant, and the electric energy is directly supplied to an electrolytic water hydrogen production unit; a circulating sewage outlet of the gasification furnace is connected with the electrolytic water hydrogen production unit through a second absorption tower, a hydrogen outlet of the electrolytic water hydrogenation unit is connected with a methanation unit after being combined with a low temperature methanol washing unit outlet, and an oxygen outlet of the electrolytic water hydrogen production unit is connected with a corresponding device. By adopting the system, not only can the requirement of high-purity hydrogen for the reduction of methanation catalyst be met, but also the hydrogen-carbon ratio in the synthesis gas of a conversion working section can be supplemented by adopting the hydrogen with relative high purity, the load produced by the conversion working section in the conventional coal natural gas process can be reduced, and the utilization rate of carbon can be increased.

Description

technical field [0001] The invention belongs to the technical field of natural gas, and in particular relates to a system for producing hydrogen by electrolysis and coal-to-synthesis gas to produce natural gas. Background technique [0002] In the existing coal-to-natural gas production, the crude gas after coal gasification must be adjusted through the conversion section to adjust the hydrogen-carbon ratio, which will convert a large amount of carbon monoxide into carbon dioxide, reducing the effective utilization of carbon, and also increasing the downstream low-temperature methanol washing. Unit load, resulting in a waste of energy. [0003] The coal-to-natural gas process will produce a large amount of industrial sewage, and the unrestricted discharge will not only pollute the environment, but also cause a lot of waste of water resources; at the same time, a large amount of process heat energy will be generated in the production process. Many factories choose to directly...

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Problems solved by technology

Hydrogen production by electrolysis of water has not been applied to coal-to-natural gas production

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