Secondary air distribution method for active corrosion prevention of opposed firing boiler

Abstract

The invention relates to a secondary air distribution method for active corrosion prevention of an opposed firing boiler, which comprises the following steps of performing flow-equalizing transformation on a flow field of a layer secondary air duct, measuring the air volume of the layer secondary air duct, the real-time reducing atmosphere concentration of a water-cooled wall side wall and the nitrogen oxide concentration of a hearth outlet, and calculating the real-time excess air coefficient of a hearth main combustion area, setting standard values of an excess air coefficient, reducing atmosphere concentration and nitrogen oxide concentration, defining a standard range of the opening degree of an air door of the layer secondary air duct, and adjusting the opening degree of the air door of the layer secondary air duct.The uniformity and stability of airflow in the secondary air duct of the layer is improved, the accuracy of online measurement of the secondary air volume of the layer is improved, precise air distribution staged combustion of secondary air of a boiler hearth is achieved, pulverized coal combustion of a main combustion area is enhanced, scouring of pulverized coal particles to the side wall water cooling wall is reduced, the reducing atmosphere at the position close to the side wall water cooling wall is controlled, and the purpose of actively preventing and controlling high-temperature corrosion of the side wall water cooling wall of the opposed firing pulverized coal boiler is achieved.

Description

technical field [0001] The invention belongs to the field of coal-fired boilers, and in particular relates to a secondary air distribution method for active anticorrosion of a hedging-fired boiler. Background technique [0002] With the comprehensive promotion of ultra-low emission and energy-saving transformation of coal-fired power plants, domestic coal-fired power plants are x To meet the requirements of ultra-low emission, the boiler operates with low oxygen in depth and low nitrogen, and the proportion of over-burning air is over 30%. 2 The concentration of S increased significantly, and the local concentration even reached 800 mg / m 3 The above objectively caused the serious high temperature corrosion problem of the water wall. [0003] Hedge-fired boilers with high-temperature corrosion in China generally use metal spray protection on the surface of the water-cooled wall to passively respond. However, after spraying on the surface of the water wall of boilers in som...

AI Technical Summary

Problems solved by technology

However, in practical applications, for boilers with poor combustion adaptability, the risk of wall-mounted air modification is relatively high, and the air volume of wall-mounted air basically does not participate in the combustion in the furnace, and may even cause combustion-related side effects, such as overheating of the high-temperature heating surface and wall temperature, and coking In some power plants, the damper of the wall-mounted air is fully closed or kept at a small opening below 30% during the operation of some power plant boilers. The problem of coking of the wall-mounted air nozzles occurs from time to time, and the protective effect of the wall-mounted air is difficult to fully exert

In addition, some power plants are limited by the air volume and pressure of the existing fans, so it is impossible to implement wall-mounted wind retrofits

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