Air staged-combustion vertical and horizontal combined arrangement type over fire air system for tangential boiler

Abstract

The invention discloses an air staged-combustion vertical and horizontal combined arrangement type over fire air system for a tangential boiler. The air staged-combustion vertical and horizontal combined arrangement type over fire air system for the tangential boiler comprises a hearth, a hot air box, a pulverized coal pipeline, a primary air nozzle, a secondary air nozzle, a compact over fire air nozzle, a corner separation over fire air nozzle, a wall type separation over fire air nozzle and the like. According to the system, the tangential boiler is innovated in the conventional hearth height direction on the aspect of the way that over fire air is arranged at the corner, and the purposes of decreasing the excess air coefficient of a main combustion area and reducing NOx generation are realized by arranging corner separation over fire air nozzle and the wall type separation over fire air nozzle which are controlled independently on the upper portion of the main combustion area. By the adoption of the air staged-combustion vertical and horizontal combined arrangement type over fire air system, a sufficient over fire air rate, a reasonable reduction area length, good later-stage intra-boiler mixing and sufficient burn-out time can be guaranteed, smoke remaining rotation and temperature deviation can be effectively eliminated, the requirement for restraining NOx generation and the requirement for promoting pulverized coal to be burnt out are both considered, and the requirements for achieving safety operation of the boiler and being economical and environmentally friendly are met.

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...

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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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