Hot air and exhaust gas double-medium powder delivery method and exhaust gas and hot air mixer

Abstract

The invention provides a hot air and exhaust gas double-medium powder delivery method and an exhaust gas and hot air mixer and relates to a powder delivery method and a special exhaust gas and hot air mixer in the method, aiming at solving the problems that tertiary air in a hot air powder delivery system is not beneficial to the discharge reduction of NOx and the steady combustion of an exhaust gas powder delivery system boiler, and a primary air pipeline inlet and a valve thereof are severely abraded. Exhaust gas from an exhaust gas pipeline and hot air from a hot air pipeline are mixed and used as primary air together for delivering powder. A plurality of exhaust gas nozzles are dispersedly inserted on the side wall of an air distribution main pipe and communicated with the inner cavity of the air distribution main pipe, a plurality of round platform shape shrinkage pipes are positioned at the outside of the air distribution main pipe, the big ends of the round platform shape shrinkage pipes are respectively communicated with the inner cavity of the air distribution main pipe, and the small ends of the round platform shape shrinkage pipes are respectively communicated with one end of a plurality of mixed pipes. The invention obviously reduces the temperature of the primary air and the temperature of a main combustion area in a furnace, is beneficial to the discharge reduction of the NOx, meets the stability requirement of the combustion of the boiler and relieves the abrasion of the primary air pipeline inlet and the valve thereof.

Description

technical field [0001] The invention relates to a powder feeding method and a dedicated exhaust gas hot air mixer used in the method, and relates to the technical field of coal-fired boilers. Background technique [0002] my country's existing thermal power plants and power plants burning lean coal and anthracite widely use intermediate storage bins and hot air powder feeding systems, which are beneficial to the stable combustion of boilers. But in these boilers, the tertiary air (exhausted air) is usually arranged on the uppermost layer, and there are one or two layers of secondary air nozzles below it. The air volume of the tertiary air is generally more than 18% of the total air volume, which contains 10-15% of the total boiler coal powder. The excess air coefficient in the tertiary wind is high, often above 2.0. Although the introduction of the tertiary air has the effect of air staged combustion to a certain extent, due to the limited air volume of the tertiary air, t...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of high NOx emission in the boiler of the existing hot air powder feeding system, and the problems of poor combustion stability of the boiler and serious wear of the inlet of the primary air pipe and its valve in the boiler of the exhaust gas powder feeding system, and propose a Hot air and exhaust air dual medium powder feeding method and exhaust air hot air mixer

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