High oxygen concentration oxygen-enriched pulverized coal fractional combustion method and device therefor

Abstract

The invention relates to a high oxygen concentration oxygen-enriched pulverized coal fractional combustion method and a device therefor. The invention has the technical scheme that a boiler type with three stages of series connection hearths is adopted; when in combustion, the pulverized coal and oxygen are respectively put into the hearths for combustion according to the proportion in the combustion process; all recycling flue gas is pumped back into the first hearth and is blended with part of the oxygen filled in the first hearth for transmitting the pulverized coal for the first hearth; part of the flue gas generated by the first hearth is blended with part of the oxygen filled in the second hearth for transmitting the pulverized coal for the second hearth; and part of the flue gas generated by the second hearth is blended with part of the oxygen filled in the third hearth for transmitting the pulverized coal for the second hearth. The total concentration of O2 in the boiler reaches 70-80%; as the next stage of hearth adopts the flue gas generated by combustion of the previous hearth as dilute gas, the actual concentration of O2 in every stage of hearth is within the range of 30-40%. The quantity of the recycling flue gas is much less than that in the current oxygen-enriched combustion boiler, and the electricity consumption in the running of a flue gas circulation fan is obviously lowered.

Description

A method and device for staged combustion of high-oxygen-concentration oxygen-enriched pulverized coal technical field The invention relates to clean combustion of pulverized coal in a coal-fired power station, in particular to a method for graded combustion of pulverized coal with high oxygen concentration and rich oxygen, belonging to the technical field of boilers. Background technique Coal-fired power plants are a concentrated emission source of CO2, and the separation and capture of CO2 from flue gas is the key to the implementation of CO2 capture and storage (CCS) technology. At present, most boilers use air as the fuel oxidant, and the CO2 concentration in the flue gas produced by conventional air combustion is 10% to 14%, and the rest is mainly N2. Separating and capturing CO2 from N2 is energy-intensive. The oxygen-enriched combustion technology produces very little N2 in the flue gas, which is convenient for compression and cooling to obtain liquid CO2, and at t...

AI Technical Summary

Problems solved by technology

However, in the current combustion mode, since the pulverized coal needs to be transported by the combustion-supporting gas to the boiler for combustion, if the amount of circulating flue gas is too small, the oxygen concentration in the pulverized coal transport gas will be too high, which will easily lead to the occurrence of pulverized coal in the pulverized coal transport pipe. Spontaneous combustion or even deflagration

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