Circulating fluidized bed gasification device with gasification auxiliary bed and gasification method

Abstract

The invention provides a circulating fluidized bed gasification device with a gasification auxiliary bed and a gasification method. The gasification device includes a gasification furnace (1), a gas-solid separator (2), and the gasification auxiliary bed, wherein a fuel inlet, a gasifying agent inlet, a furnace return gas inlet, a furnace discharge gas outlet, a bottom slag outlet, and a materialreturn opening are formed in the gasification furnace (1); the inlet of the gas-solid separator (2) communicates with the furnace discharge gas outlet of the gasification furnace (1), the gasificationauxiliary bed includes a circulating material inlet, the gasifying agent inlet, the furnace return gas outlet, and a furnace return carbonaceous material outlet, the circulating material inlet of thegasification auxiliary bed communicates with a solid-phase outlet of the gas-solid separator (2), the furnace return gas outlet of the gasification auxiliary bed communicates with the furnace returngas inlet of the gasification furnace (1), and the furnace return carbonaceous material outlet of the gasification auxiliary bed communicates with the material return opening of the gasification furnace (1). According to the gasification device and the gasification method, the carbon conversion rate of the gasification device can be improved.

Description

technical field [0001] The invention relates to the technical field of fuel gasification, in particular to a circulating fluidized bed gasification device with a gasification auxiliary bed and a circulating fluidized bed gasification method with a gasification auxiliary bed. Background technique [0002] Coal gasification is one of the core technologies for clean and efficient utilization of coal, and it is the basis for the development of coal chemical process industries such as coal-based chemicals, coal-based clean fuels, industrial gas and polygeneration systems. [0003] The current coal gasification technology can be divided into fixed bed gasification technology, fluidized bed gasification technology and entrained bed gasification technology according to the gas-solid flow form. The fixed bed coal gasification technology uses lump coal as raw material. There are obvious drying layers, pyrolysis layers, gasification layers and combustion layers in the gasifier. The sla...

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Problems solved by technology

In order to avoid slagging, the temperature of the lower part of the furnace should not be too high, and the temperature is limited. Therefore, the range of increasing the overall temperature of the gasifier by increasing the temperature of the lower part of the furnace is limited

In the upper part of the furnace where high temperature is required to promote the gasification reaction of carbon and carbon dioxide, the temperature is limited, resulting in low carbon conversion rate of circulating fluidized bed gasification furnace, and high carbon content in fine powder ash, which is not conducive to circulating fluidized bed coal gasification technology application

Although the temperature distribution in the height direction of the gasifier furnace can be changed through the graded air distribution, so that the operating temperature of the gasifier is no longer limited by the temperature of the lower part of the furnace, the oxygen or air introduced by the graded air distribution reacts preferentially with the coal gas instead of with the coal gas. The reaction probability of carbon in this area is very small, and the promotion effect on the gasification reaction performance of the system is not significant enough

Although the fine powder ash discharged from the gasifier can be processed into high-temperature gas and ash by building another high-temperature reaction device, another system needs to be built, which greatly increases equipment investment and operating costs, and may affect the circulating fluidized bed. Stable operation and coal type adaptability of gasifier

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