System and blending combustion method for coal-fired power station boiler for large-proportion blending combustion of semi-coke

Abstract

The invention relates to a system and a blending combustion method for a coal-fired power station boiler for large-proportion blending combustion of semi-coke. According to the system and the blendingcombustion method, the problems that the low-volatile semi-coke fuel is difficult to fire, poor in burnout performance and high in NOx emission during combustion are solved; optimization of a pulverizing system, dense-dilute regional combustion of semi-coke fuel, in-furnace layered blending combustion of the semi-coke and bituminous coal, pure oxygen over fire air arrangement and cold energy comprehensive utilization are comprehensively considered; a four-corner tangential combustion mode is adopted, a boiler hearth five-zone combustion environment is built, and a power station boiler systemfor large-proportion blending combustion of the semi-coke is developed, so that the proportion of blending combustion of the semi-coke is larger than or equal to 45%; low NOx emission of an outlet ofa hearth is realized while high-efficiency combustion of the semi-coke is realized; and low-temperature O2 and low-temperature N2 which are close to 0 DEG C and are obtained by air separation and obtained through an air-temperature type gasifier are used for realizing deep condensation of desulfurized clean flue gas, so that water in the clean flue gas is reduced to the maximum degree, corrosion of a chimney is reduced, white smoke is also eliminated, and visual pollution around a power station is reduced.

Description

technical field [0001] The invention belongs to the field of power generation equipment, and in particular relates to a coal-fired power station boiler system and a method for blending and burning semi-coke in a large proportion. Background technique [0002] According to the different characteristics of the reactivity of coal in different conversion stages, it is one of the most reasonable ways to utilize coal energy to realize coal graded conversion and energy cascade utilization. Semi-coke is a low volatile solid carbon product obtained by dry distillation and pyrolysis of non-caking or weakly caking high-volatile bituminous coal under medium and low temperature conditions. my country's low-rank coal reserves are close to 500 billion tons, accounting for about 42% of the proven coal reserves. This is a type of coal with a low degree of coalification. The graded conversion of low-rank coal refers to the coal utilization method in which oil and gas are extracted from coal ...

AI Technical Summary

Problems solved by technology

However, when the existing bituminous coal-fired power station boilers are mixed with semi-coke, the carbon content of the boiler fly ash will increase, and it will not be able to operate at full load. x Issues such as high emissions

At present, domestic coal-fired units can achieve safe and stable blending of about 30% semi-coke, but it is found that with the increase of blending ratio, the carbon content of fly ash of coal-fired power plant boilers increases, and the boiler efficiency decreases

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