Biomass fractionation conversion and coal-fired boiler coupling electricity generating method and system based on medium and low temperature dual fluidized bed

Abstract

The invention discloses a biomass fractionation conversion and coal-fired boiler coupling electricity generating method and system based on a medium and low temperature dual fluidized bed. The methodcomprises the following steps that 1, biomass with the high water content, a high temperature bed material from a fluidized bed gasifier and a fluidizing agent are subjected to pyrolysis treatment, pyrolysis gas is generated, and meanwhile a bed material and pyrolysis charcoal mixture is obtained; 2, the obtained bed material and pyrolysis charcoal mixture, the biomass raw materials, the gasifyingagent and hot-blast air from the coal-fired power plant boiler are subjected to a high temperature gasification reaction to generate synthesis gas, and remaining inert substances gasified by the biomass raw materials form slags to be discharged; 3, the pyrolysis gas and synthesis gas are adopted as heat sources to be supplied into the coal-fired power plant boiler for combustion and heat release,generated steam is used for electricity generation, and meanwhile obtained exhaust gas is exhausted. The biomass raw materials can be subjected to classified utilization, biomass raw material pyrolysis and gasification segmentation conversion can be achieved, and products obtained in conversion sections can achieve efficient poly-generation.

Description

technical field [0001] The invention relates to the technical field of biomass conversion and utilization, in particular to a method and system for coupling power generation of biomass graded conversion and coal-fired boiler based on medium and low temperature dual fluidized beds. Background technique [0002] Under the condition of power shortage and abundant biomass energy in our country, biomass power generation has broad development prospects. Under the dual pressure of energy and the environment, vigorously developing clean and renewable energy has become a very urgent worldwide issue before governments all over the world. China is a large agricultural country with abundant agricultural and forestry biomass resources, huge quantities and diverse varieties. Under the background of favorable policies, the utilization of biomass resources has achieved considerable development in China, but at the same time there are still in-depth problems in gasification technology and eq...

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Problems solved by technology

[0004] However, the existing biomass gasification process has the problems of low gasification pressure, high tar content, poor gas quality, and complex system. Cool down, pressurize, and then transport it to the coal-fired boiler for combustion. This method has the problems of tar adhesion and heat exchanger blockage during the transport and cooling process of the syngas. Although the cooling heat exchange device in some projects uses heat transfer oil as the cooling medium , but there are still problems such as complex system, poor stability of heat transfer oil, and high price

In addition, before the synthesis gas is sent to the coal-fired boiler, it needs to be transported by a booster fan, and the booster fan has long-term reliability problems in the high-temperature environment containing dust and oil, and the frequent maintenance of the fan affects the overall reliability of the system. run

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