Methanation technology for preparing SNG from coal-based synthetic gas

Abstract

A methanation technology or preparing SNG from coal-based synthetic gas comprises the following steps: methane synthetic gas from a coal gas purifying workshop section is finely desulphurized, and the desulphurized synthetic gas is divided into four virgin gases A, B, C and D; the virgin gas A and circulation gas simultaneously enter the first segment of a first methane synthesis reactor, first segment outlet gas and the virgin gas B simultaneously enter the second segment of the first methane synthesis reactor, the outlet gas of the second segment of the first methane synthesis reactor and the virgin gas C simultaneously enter the first segment of a second methane synthesis reactor, the outlet gas of the first segment of the second methane synthesis reactor and the virgin gas B are mixed to form second segment gas, and the second segment gas enters the second segment of the second methane synthesis reactor; and the outlet gas of the second methane synthesis reactor is cooled, parts of the cooled gas is pressurized without water separation, the pressurized gas returns to the inlet of the first segment of the first methane synthesis reactor as circulation gas, the remaining gas sequentially enters a third methane synthesis reactor and a fourth methane synthesis reactor and undergoes a methane synthesis reaction, the methane dry base content of the outlet gas of the fourth methane synthesis reactor is greater than 95%, and the outlet gas of the fourth methane synthesis reactor is cooled and dehydrated to obtain the SNG.

Description

technical field [0001] The invention relates to methanation technologies such as city gas methanation and coal-based synthetic natural gas (SNG), and provides a new methanation process for preparing SNG from coal-based synthesis gas. Background technique [0002] Natural gas is an efficient and clean energy, but due to the lack of natural gas resources in my country, its supply is far from meeting market demand. Coal-to-synthetic natural gas (Synthetic Natural Gas) is an important way to alleviate the contradiction between supply and demand of natural gas, and it is a new type of coal chemical project supported by the country during the "Twelfth Five-Year Plan". [0003] A person from the China City Gas Association said that the proportion of natural gas in primary energy consumption has reached 25% in the world, while it is only 3.2% in my country. The industry has basically formed such a consensus that expanding natural gas sources will play an increasingly important role...

AI Technical Summary

Problems solved by technology

[0006] The existing coal-to-synthetic natural gas methanation technology usually uses a complex device of multiple heat exchangers and gas cyclers to control the temperature, and the amount of cycle gas used is large, which not only increases equipment investment but also greatly increases the power consumption of cycle gas

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