A polygeneration device and method for coal gas low-nitrogen oxide combustion power generation

Abstract

The invention provides a poly-generation apparatus and method using low nitrogen oxides in coal gas for combustion power generation. According to the invention, one or more low rank coal selected from the group consisting of brown coal, long flame coal, sub-bituminous coal and soft coal are added into a fine coal upgrading conversion reactor for rapid conversion, crude coal gas produced after conversion undergoes dedusting and purifying, oil-gas separation, and desulphurization and purification; and purified coal gas is successively injected into a boiler for combustion through graded combustion nozzles. Compared with the prior art, the invention has the following advantages: a desired air excess coefficient is small, combustion temperature is lower than a typical temperature--1400 DEG C at which a great amount of thermal NOx is produced, so production of thermal NOx in the process of combustion is radically inhibited and production of fuel NOx and rapid NOx is avoided; the concentration of respirable particulates like SO2, PM2.5 and PM10 in combustion flue gas is extremely low, and ultra-low concentration discharge of SO2 and NOx can be realized; and the combustion flue gas is almost free of heavy metals like lead, chromium, cadmium, arsenic and mercury.

Description

technical field [0001] The invention relates to the technical field of high-efficiency clean conversion and utilization of coal and clean combustion of coal gas for power generation, in particular to a polygeneration device and method for coal gas low-nitrogen oxide combustion power generation. Background technique [0002] During the coal combustion process of power plant boilers, there are three main sources of NOx, namely, thermal NOx, fuel NOx, and rapid NOx. At normal combustion temperatures, NOx accounts for more than 90% of the NOx produced by coal combustion, and NO 2 Accounted for 5% to 10%. At present, the NOx control methods in coal-fired power plant boilers are mainly divided into three categories: one is to use low-nitrogen fuels or denitrify fuels before combustion; the other is to use low-NOx combustion methods; the third is to denitrify coal-fired flue gas. Coal contains the most nitrogen, followed by fuel oil, and generally there is no or very little nitro...

AI Technical Summary

Problems solved by technology

However, due to the high dust concentration, the wear and corrosion of the catalyst is serious, and it can also cause the micropore blockage of the catalyst, which affects its life and activity; the SO in the flue gas 2 Under the catalytic action of the denitrification catalyst, it will be converted into SO 3 , the difficulty of subsequent desulfurization increases

For ②, although the dust concentration is reduced, it is necessary to add a flue gas reheating system, which increases investment and operating costs, and there is also SO in the flue gas 2 will be converted to SO 3 The problem

For ③, although there is no impact of dust erosion in the flue gas on the catalyst life and activity, there is no SO in the flue gas 2 will be converted to SO 3 However, it also faces the problem of adding a flue gas reheating system, which increases investment and operating costs

At the same time, the biggest problem with the SCR method is the use of ammonia, and heavy metals such as lead, chromium, cadmium, and arsenic that are ubiquitous in coal-fired flue gas may poison and deactivate the SCR catalyst, seriously affecting its normal life.

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