Method and system for preparing gas by fixed bed gasifier

Abstract

The invention provides a method and a system for preparing gas by a fixed bed gasifier. The method for preparing gas comprises steps as follows: a coal lock containing feed coal is pressurized by the first part of carbon dioxide exhaust gas; the second part of the carbon dioxide exhaust gas is introduced into the fixed bed gasifier before a vapor inlet of a gasification agent pipe; an introduced gasification agent, the second part of the carbon dioxide exhaust gas and the pressurized feed coal react in the fixed bed gasifier, and crude gas and gasified ash are obtained. The carbon dioxide exhaust gas is mainly used as the raw material and introduced into the gasifier, and CO can be prepared by a reduction reaction; a heat storage type heat carrier CO2 performs gas stripping on volatile matter of coal at the dry distillation stage, and effects of thickening of a dry distillation bed and high yield of coal tar can be realized. Therefore, the system has the functions of preparation of a large amount of oil and gas, recovery of carbon dioxide exhaust gas and the like, and is beneficial to energy conservation and emission reduction.

Description

technical field [0001] The invention relates to the technical field of coal chemical industry, in particular to a method and system for gas production by a fixed-bed gasifier. Background technique [0002] In the field of coal chemical industry, coal gasifier is the main equipment of coal gasification, and it is a furnace that uses coal as gasification fuel to produce combustible gas. Typical industrial coal gasifier types include: UGI furnace, Lurgi furnace, Winkler furnace (Winkler), Texaco furnace (Texaco) and Dow Chemical coal gasifier (Dow Chemical). According to the contact mode of solid and gas, coal gasifier can be divided into four types: fixed bed, fluidized bed, entrained flow bed and molten bed. At present, the fixed-bed gasifiers in operation mainly include Lurgi gasifiers and so on. The structure of the Lurgi furnace is as follows figure 1 as shown, figure 1 It is a structural schematic diagram of some existing Lurgi furnaces. figure 1 Among them, 1 is a c...

AI Technical Summary

Problems solved by technology

For example, some large coal chemical and petrochemical plants currently emit a large amount of CO 2 Gas, especially some large-scale coal chemical enterprises that produce clean gas with low-temperature methanol washing technology, the waste gas emitted includes CO with a purity of more than 90%. 2 gas, which causes energy waste and environmental pollution

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