Combustion method and device for pulverized coal hot air furnace

Abstract

The invention relates to a combustion method and a combustion device for a pulverized coal hot air furnace. The method comprises the following steps of: simultaneously introducing gas and air into a gas burner, igniting the gas and heating a pulverized coal combustor to the temperature of more than 800 DEG C; feeding pulverized coal with the granularity of 180 meshes into the pulverized coal combustor, igniting the pulverized coal and continuously combusting the pulverized coal in the pulverized coal combustor; raising the temperature of an inner cavity of the pulverized coal combustor to be between 1,000 and 1,350 DEG C, injecting flames into a combustion chamber through a flame outlet of the pulverized coal combustor, and supplying the air through a secondary air inlet for full combustion; exhausting the burned fine particles which are carried by high-temperature hot air through an outlet of the combustion chamber, making the air pass through an adjustable air inlet, and making backflow flue gas pass through a backflow flue gas inlet and rotate and rise in an air sleeve from the lower part of an outer sleeve; and recovering waste heat, arranging a natural mixed air pipe and introducing the air in the center of high-temperature flue gas for mixing, and conveying the hot air to users through a hot air furnace outlet when the hot air is adjusted to the needed temperature. The invention has the characteristics that: the cost is reduced by utilizing low-price coal and brown coal, the combustion chamber and a mixed air chamber are mixed into a whole, the pulverized coal is fully combusted, carbon residues are about 1 percent of ash, the thermal efficiency is over 90 percent, and the like.

Description

technical field [0001] The invention belongs to the technical field of hot blast stoves, in particular to a pulverized coal hot blast stove combustion method and device. Background technique [0002] At present, there are several types of coal-fired hot blast stoves at home and abroad. One is the fixed grate hot blast stove, which is suitable for miniaturization and has a simple structure. The smoke and dust are black and polluted, the thermal efficiency is only 60%, and the residual carbon in the ash is 20%. Only after mixing the air chamber can it be adjusted to the required temperature; It is suitable for miniaturization and large-scale operation. It can burn raw coal, with a thermal efficiency of 70%, about 10% of residual carbon in the ash, good smoke and dust removal, and the Ringelmann blackness of the smoke and dust can reach 0-1 grade. , increase heat loss, reduce efficiency, and occupy a large area. The coal used is the second-class bituminous coal with a calorifi...

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Problems solved by technology

[0002] At present, there are several types of coal-fired hot blast stoves at home and abroad. One is the fixed grate hot blast stove, which is suitable for miniaturization and has a simple structure. The smoke and dust are black and polluted, the thermal efficiency is only 60%, and the residual carbon in the ash is 20%. Only after mixing the air chamber can it be adjusted to the required temperature; It is suitable for miniaturization and large-scale operation. It can burn raw coal, with a thermal efficiency of 70%, about 10% of residual carbon in the ash, good smoke and dust removal, and the Ringelmann blackness of the smoke and dust can reach 0-1 grade. , increase heat loss, reduce efficiency, and occupy a large area. The coal used is the second-class bituminous coal with a calorific value above 4300 kcal. Low-rank coal and lignite cannot be burned because the calorific value is low and the water content is about 30%. The third type is The pulverized coal combustion hot blast stove is made of several types of pulverized coal nozzles, which spray the mixture of air and pulverized coal into the hot blast stove for combustion. The advantage is that the coal is fully burned, the energy saving effect is good, and the residual carbon in the ash is less than 4%. The coal quality requirement is high, generally more than 5500 kcal. The combustion chamber of the hot blast stove needs to use oil or other fuels in advance and preheat to a certain temperature before injecting coal powder for combustion. The combustion chamber requires a large volume and needs to be Set up a mixed air chamber to adjust to the required temperature. Low-rank coal and lignite cannot be burned.

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