Method and device for preparing synthetic natural gas

Abstract

The invention provides a method for preparing a synthetic natural gas. The method comprises the step of performing a methanation reaction on a raw material gas which contains CO, CO2 and H2 in the presence of liquid saturated water. The invention also provides a device for implementing the method. The device comprises a methanator which is provided with a raw material gas inlet, a product outlet,and a nickel-based catalysts and liquid water inlet. The method of the invention is convenient and easy, and is suitable for various raw material gases; the ratio of H2 to CO in the raw material gas is improved by a water gas shift reaction; and a great amount of heat released by the methanation reaction is removed fast by vaporizing the liquid saturated water, so that a reaction temperature is controlled effectively, high-temperature carbon deposit of a catalyst is slowed down and the service life of the catalyst is prolonged. The device of the invention has the characteristics of simple structure and convenient operation.

Description

technical field [0001] The invention relates to a method for preparing synthetic natural gas by utilizing CO-containing gas, especially a method for preparing synthetic natural gas through methanation reaction. technical background [0002] In response to the lack of natural gas in my country, especially the gas shortage in the north in the winter of 2009, the development of synthetic natural gas preparation technology has become a research focus. An important step in the process of producing synthetic natural gas is the CO / CO 2 Methanation reaction to increase CH in product gas 4 content, the reaction equation is as follows: [0003] CO+3H 2 =CH 4 +H 2 o [0004] CO 2 +4H 2 =CH 4 +2H 2 o [0005] When H in raw gas 2 When the :CO ratio is less than 3, a water vapor shift reaction is required to increase the H 2 : CO ratio, the conversion reaction equation is: [0006] CO+H 2 O=CO 2 +H 2 [0007] Among them, the methanation reaction is a strongly exothermic ...

AI Technical Summary

Problems solved by technology

However, there are few reports on the reaction process. In order to achieve the purpose of controlling the temperature rise of the reaction, the general method is to reduce the amount of reaction by reducing the content of CO in the feed gas, thereby reducing the heat of reaction and controlling the temperature rise of the reaction. For example, in the patent "A method for producing synthetic natural gas by using coke oven gas" (publication number CN1919985) adopts a dilution method and a two-stage conversion method, wherein the dilution method is to mix the methanation product back into the feed gas, and the cycle gas is relatively high, while the two-stage Imported CO and CO 2 The concentration is still relatively high; the patent "A Methanation Process for Synthetic Natural Gas Preparation Using Coke Oven Gas" (publication number CN101508922A) adopts a multi-stage methanation process, and its raw material gas is coke oven gas, H 2 : The CO ratio is much greater than 3, and there is a serious phenomenon that the product gas is back-mixed into the raw material gas in the process; the patent (publication number CN101560423A) "a method and equipment for preparing substitute natural gas" also adopts the method of mixing the product gas The method of fresh feed gas to control the temperature rise of the reaction

Images