Gasifier, catalytic gasification system and catalytic gasification process

Abstract

The invention discloses a gasifier, a catalytic gasification system and a catalytic gasification process, relates to the technical field of coal gasification and aims to solve the problems that when hydrogen and carbon monoxide in raw coal gas are extracted and injected into the gasifier again in the prior art, a coal gasification reaction is likely to be impeded, and slag bonding on a distribution plate or explosion is caused easily. The gasifier comprises a casing, wherein a coal gasification chamber and a methanation chamber are formed in the casing; a feeding pipe, a first gas inlet pipe, a second gas inlet pipe and an exhaust pipe are connected on the casing; the feeding pipe and the first gas inlet pipe are communicated with the coal gasification chamber; an overflow structure is arranged between the coal gasification chamber and the methanation chamber; the second gas inlet pipe is communicated with the methanation chamber; the coal gasification chamber and the methanation chamber are both communicated with the exhaust pipe. The gasifier is used for increasing the content of methane in exhausted raw coal gas.

Description

technical field [0001] The invention relates to the technical field of coal gasification, in particular to a gasification furnace, a catalytic gasification system and a catalytic gasification process. Background technique [0002] Catalytic gasification belongs to the advanced third-generation gasification technology. It is an important way of clean and efficient utilization of coal, and one of the effective process methods for coal-to-natural gas. [0003] Existing catalytic gasification devices usually use a fluidized bed, adding coal, catalyst and gasification agent to the fluidized bed to simultaneously carry out two reactions of coal gasification and methanation to produce crude gas. In order to increase the methane content in the raw gas, it is necessary to extract the mixed gas composed of hydrogen and carbon monoxide from the discharged raw gas, and pass it into the fluidized bed again to carry out the methanation reaction again. [0004] However, when hydrogen and ...

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Problems solved by technology

[0004] However, when hydrogen and carbon monoxide are fed into the fluidized bed again, the content of hydrogen and carbon monoxide in the fluidized bed is relatively large, which will easily hinder the coal gasification reaction between the coal material and the gasification agent, reduce the conversion rate of carbon, and thus Prolong the solid phase residence time and reduce the gasification capacity of the gasifier

At the same time, hydrogen and carbon monoxide cannot enter the gasifier through the distribution plate together with the oxygen-containing gasification agent, otherwise a large amount of combustible gas will burn violently at the distribution plate, which will cause slagging at the distribution plate, and in severe cases, it will cause Explosion, in order to avoid this problem, hydrogen and carbon monoxide can be fed into the gasifier through the upper oxygen-free zone, and the gasification agent is still introduced from the distribution plate at the bottom. Under the premise of a certain overall gas volume, the gas volume introduced from the bottom is reduced, which affects the fluidization quality of the fluidized bed. If a certain amount of gasifying agent is added to the upper anaerobic zone, it is easy to cause gas entrainment in the crude gas. The gasification agent increases, and the gasification agent participating in the reaction decreases, thereby reducing the conversion rate of carbon

In addition, because the methanation reaction is a slow reaction, a certain gas-solid contact time is required to achieve a high methane yield when the catalyst-containing coal particles are used as the catalyst. Therefore, when hydrogen and carbon monoxide are fed into the gasifier through the upper anaerobic zone, It is necessary to increase the height of the gasifier to prolong the gas-solid contact time. However, when the height of the gasifier is large, it is easy to affect the fluidization quality in the fluidized bed, and at the same time, the temperature difference along the height direction in the fluidized bed is relatively large. Large, low gasification quality

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