A system and method for co-combustion of biomass fuel and semi-coke

Abstract

The invention discloses a biomass fuel and semi-coke mixed burning system and method. Aiming at the problems of low calorific value of biomass gasification products, difficulty of semi-coke ignition steady burning, high discharge of NOx and the like, the biomass fuel and semi-coke mixed burning method is adopted, gasification is performed on biomass fuel through a gasification furnace, flammable gaseous products are fed into an ignition area and a reburning area which are arranged inside a furnace cavity, meanwhile, solid residues are fed into a main burning area for mixed burning with semi-coke, the problem of difficulty of semi-coke ignition steady burning is solved, and by means of layering mixed burning inside the furnace, a reducing atmosphere area is formed at the upper portion of the main burning area, so that burning optimization is realized, the NOx discharge quantity is reduced at the same time, and meanwhile, part of hot air inside an air preheater is fed into the gasification furnace and a two-stage cyclone separator is adopted, so that the air fan investment is reduced, the energy utilization rate is increased, and the gasification furnace efficiency is improved.

Description

Technical field [0001] The invention relates to a system and method for mixed combustion of biomass fuel and semi-coke. Background technique [0002] Among the coal varieties in my country, low-rank coal accounts for more than 55%. The low-rank coal will obtain by-product semi-coke during the fractional conversion process. Semi-coke is a low-volatile solid carbon product obtained by dry distillation and pyrolysis of high-volatile bituminous coal with no cohesion or weak cohesion under medium and low temperature conditions. Because the chemical structure of low-rank coal has more side chains and higher hydrogen and oxygen content, the semi-coke has high fixed carbon, high calorific value, high chemical activity, low sulfur content, low volatile content, and low ash content. . When the semi-coke is burned, there is very little flue gas, and no tar is formed when heated, and the thermal efficiency of combustion is significantly higher than that of coal. However, the characterist...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method that can achieve a large proportion of mixed burning semi-coke and utilize biomass, pyrolysis and gasification of biomass, co-firing of gasification products and semi-coke, fully improving the efficiency of biomass utilization, and solving the problem of semi-coke. Focus on the difficulty of ignition and stable combustion, improve fuel adaptability, and reduce furnace outlet NO x System and method for co-combustion of concentrated biomass fuel and semi-coke

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