One-step coal-to-synthetic natural gas and its system

Abstract

The invention discloses a one-step coal-to-synthetic natural gas process and its system, including removing impurities such as H2S from normal-temperature crude gas to obtain purified gas, and the purified gas is preheated to further remove impurities such as sulfur, and then divided into two streams, The first stream of purified gas enters the adiabatic methanation reactor for methanation reaction, and the reaction gas exiting the adiabatic methanation reactor is cooled by the steam superheater and sent together with the second stream of purified gas into the isothermal methanation reactor for methanation reaction. The reaction gas exiting the isothermal methanation reactor is divided into two streams. The first stream of reaction gas is cooled and pressurized by a circulating gas compressor, and then sent to the adiabatic methanation reactor together with the first stream of purified gas, and the second stream of reaction gas is cooled. After the condensate is separated by the condensate separator, the condensate is sent to the second absorption tower of the low-temperature methanol washing device to remove CO2 and moisture to obtain synthetic natural gas; the invention has simple process, short process, low device operation and investment costs, and centralized recovery Heat energy and by-product high-quality steam.

Description

technical field [0001] The invention relates to a synthetic natural gas process and system, in particular to a one-step coal-to-synthetic natural gas process and its system. Background technique [0002] As the current smog continues to increase and environmental protection requirements continue to increase, energy conservation, emission reduction, and consumption reduction have become research hotspots in the field of coal chemical industry. As a clean and efficient energy product, natural gas has been paid more and more attention by people. In recent years, the domestic demand for natural gas has been increasing day by day. In order to meet the current domestic demand for natural gas, on the one hand, the government actively imports natural gas from abroad; Conversion, reducing transportation costs. At the same time as a strategic technical reserve to ensure my country's energy security. [0003] The traditional coal-to-natural gas process is to adjust the crude gas pr...

AI Technical Summary

Problems solved by technology

For this process, there are many high-temperature methanation equipment, the heat exchange network is complicated, and the investment cost of the device is relatively high

[0011] Based on this feature, someone proposed to use an isothermal methanation reactor to control a relatively low temperature at the outlet of the reactor by by-product saturated steam, and at the same time connect two low-temperature adiabatic methanation reactors in series. The disadvantage of this process is that it can only By-product saturated steam, the quality of which is poor and cannot be used to drive the turbine

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