Low-nitrogen combustion stokerfeed boiler with two-stage smoke recirculation function

Abstract

The invention discloses a low-nitrogen combustion stokerfeed boiler with a two-stage smoke recirculation function. Segmentation wind supply is adopted for a fire grate combustion region, and over-fire air is deployed above the secondary air in a suspended combustion region so as to organize staged combustion; smoke with the low temperature ranging from about 250 degrees to 300 degrees is extracted from a tail smoke channel and sent into a plurality of wind chambers in the front of a fire grate so as to organize the first-level smoke recirculation in the fire grate combustion region; reducibility smoke with volatile component N, namely smoke with the medium temperature ranging from about 450 DEG C to 500 DEG C is extracted from the lower region of a front arch and jet into a burnout region below a furnace arch of a hearth at a high speed to be used for organizing the second-level smoke recirculation in the hearth burnout region. With the help of two-layer staged combustion of the fire grate combustion region and the suspension combustion region and smoke recirculation in the fire grate combustion region, NOx generation is inhibited greatly; furthermore, with the help of the medium-temperature reducibility flue smoke of the second-level smoke recirculation, NO generated in the ascending smoke in the burnout region is reverted to N2, and finally efficient low-nitrogen combustion of the stokerfeed boiler is achieved.

Description

technical field [0001] The invention relates to a chain furnace, in particular to a low-nitrogen combustion chain furnace with two-stage flue gas recirculation, belonging to the technical field of industrial boiler combustion. Background technique [0002] Chain furnaces are widely used in coal-fired industrial boilers in my country. In terms of combustion organization, the chain furnace is dominated by constant-speed moving grate layer combustion, supplemented by suspended combustion formed by fine particles in the upper area of ​​the grate. The air distribution is dominated by the primary air sent from the bottom of the grate, and the secondary air from the upper part of the grate is supplemented. From the point of view of combustion concept, chain furnace can theoretically avoid NO X generated in large quantities. However, in actual operation, in order to ensure better burnout of the grate layer combustion and suspension combustion, strong wind needs to be sent into th...

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Problems solved by technology

[0004] The purpose of the present invention is in order to solve the chain furnace NO that background technology mentions x High emissions and existing combustion technology cannot achieve high efficiency and low NO x Combustion problems, and then provides a low nitrogen combustion chain furnace with two-stage flue gas recirculation

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