A tangential boiler air staging combustion vertical and horizontal combined layout overburning air system

Abstract

The invention discloses a burn-off air system arranged vertically and horizontally in a tangential boiler air staged combustion, including a furnace, a hot air box, a pulverized coal pipeline, a primary air nozzle, a secondary air nozzle, a compact burn-off air nozzle, and a corner separated combustion chamber. Exhaust air nozzles, wall-type separated overfire air nozzles, etc., this system is innovative in the conventional way of arranging the overfire air at the corner of the boiler along the furnace height direction of the tangential boiler. The corner separated burn-off air nozzle and the wall-type separated burn-off air nozzle can achieve the purpose of reducing the air excess coefficient in the main combustion area and reducing the generation of NOx. The invention can ensure sufficient burn-off air rate, reasonable reduction zone length, good post-mixing in the furnace and sufficient burn-out time, effectively eliminate residual flue gas rotation and temperature deviation, and take into account the suppression of NOx generation and the promotion of pulverized coal burn-out meet the needs of boiler operation safety, economy and environmental protection.

Description

Technical field: [0001] The invention belongs to the technical field of coal-fired power generation, and in particular relates to a tangential boiler air staged combustion vertical and horizontal combination arrangement burn-off air system. Background technique: [0002] The traditional pulverized coal power plant boiler adopts the method of air classification along the furnace height direction to suppress the formation of NOx in the furnace. The classification air is mainly composed of separated burnt air arranged at a certain height above the main combustion area. For pulverized coal boilers with tangential combustion, the overfire air is usually arranged at the corner of the furnace, and the grading air nozzle is generally arranged vertically along the furnace height direction. This single arrangement of graded air has obvious limitations, which are as follows: On the one hand, this traditional arrangement method needs to occupy a large space along the furnace height dire...

AI Technical Summary

Problems solved by technology

This single arrangement of graded air has obvious limitations, which are as follows: On the one hand, this traditional arrangement method needs to occupy a large space along the furnace height direction, which is likely to shorten the reduction zone and the burnout zone. Not only the NOx suppression effect is not good, but the carbon content of the fly ash will also increase; on the other hand, the large-scale power plant boiler has a large furnace cross-section, and the single-jet classified air arranged at the corner of the same plane has poor jet rigidity and penetrating The capacity and the ability to control the aerodynamic field in the burnout area are weak, so that the oxygen in the burnout area cannot be replenished quickly, the disturbance in the furnace is insufficient in the later stage, and the residual rotation of the furnace outlet cannot be effectively eliminated, which affects the burnout of pulverized coal and the control of steam temperature deviation

In terms of the layout of the graded air, the traditional multi-layered arrangement of the separated overburning air nozzles along the height of the furnace has a single form, which is often limited by the boiler structure and site conditions, making it difficult to meet the optimal design requirements, and the transformation cost of the corner graded air High, with many limiting factors, it is difficult to achieve high-efficiency and low-NOx combustion

Furthermore, the operation adjustment method of the traditional graded air is relatively simple, and it is difficult to effectively take into account the needs of low nitrogen, burnout and effective elimination of residual flue gas rotation at the furnace outlet

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