Two-stage down-suction biomass gasifier

Abstract

The present invention relates to a two-stage down-suction biomass gasifier, the upper part of a gasifier body is connected with a pyrolysis tube, a feed auger is arranged in the pyrolysis tube, the pyrolysis tube is provided with a pyrolysis gas outlet, one end of the pyrolysis tube is connected with a feed hopper, a side upper surface of a feed port of the pyrolysis tube is provided with a returning ash inlet, the feed hopper is internally provided with a two-stage cut-off brake valve, the other end of the pyrolysis tube is communicated with an accumulation ash carbon layer in the gasifier body by an ash falling pipe, the ash falling pipe is internally provided with a two-stage ash falling pipe cut-off brake valve and an ash falling pipe air inlet, an ash removal furnace grate, an ash retainer ring and an ash removal device are arranged under the accumulation ash carbon layer of the gasifier body, the ash removal device is connected with an ash discharge auger by an ash collection hopper, and the ash discharge auger is connected with the returning ash inlet. Tar efficient removal and biomass energy efficient conversion can be realized by pyrolysis and solid product separation and difference processing methods, and by homogeneous partial oxidation of pyrolysis components and smoldering combustion oxidation activation of solid coke, reactivity of the pyrolysis components and the solid coke are enhanced, and efficient tar removal and gasification conversion effects can be ultimately realized.

Description

technical field [0001] The invention relates to a biomass gasification furnace, in particular to a biomass gasification furnace of the direct pyrolysis stage of biomass and returned ash and the high-temperature gasification stage of active coke. Background technique [0002] Gasification is an important conversion method of biomass energy, which has the characteristics of cleanness, high efficiency, strong fuel adaptability and flexible operation, and has broad application prospects. Among various biomass gasification technologies, the downdraft gasifier has the lowest tar content in the gas produced, about 0.5g / Nm 3 ; while the suction type is the most, up to 50g / Nm 3 . Although the existing downdraft gasification technology has the lowest tar content in the produced gas, there are still problems such as poor stability of the produced gas quality, small gasification scale, and low energy utilization rate. [0003] Although the tar content of the traditional downdraft bio...

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Problems solved by technology

[0004] Since biomass itself is a poor conductor of heat, if the method of indirect heating and pyrolysis using a pyrolysis cylinder will cause a large heat transfer resistance, which is quite unfavorable to the pyrolysis process, the insufficient pyrolysis will make the tar removal process still difficult. There is tar precipitation, and the reactivity of coke is not fully activated, which is unfavorable for further removal of tar, and it is also the main reason for the low conversion rate of carbon elements

[0005] In a staged downdraft gasifier, the reactivity of coke to tar is the key factor determining the tar content in the gas produced by the downdraft gasifier. During the gasification process, a large number of pore blockages and deactivation processes occur. In order to further reduce the tar content and improve the gasification efficiency during the gasification process, other more effective methods need to be adopted.

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