Efficient low-pollution W-shaped flame boiler OFA (over fire air) device and method

Abstract

The invention relates to an efficient low-pollution W-shaped flame boiler OFA (over fire air) device and method. Conventional large-capacity W-shaped flame boiler OFA equipment occupies large space and is complex in structure. The OFA device comprises main combustion zone OFA nozzles, wing wall OFA nozzles, an upper hearth, an annular air duct and an air box provided with OFA layers, and is characterized in that one end of each main combustion zone OFA nozzle is fixed on the water-cooled wall, close to the throat position, of the upper hearth, and the other end of each main combustion zone OFA nozzle is fixed on the air box; one end of each wing wall OFA nozzle is connected onto the annular air duct through a pipeline, and the other end of each wing wall OFA nozzle is connected onto the water-cooled wall, close to the side wall position, of the upper hearth; and each OFA nozzle comprises a center air duct, an outer annular air duct and a cyclone, and the center air ducts are located in the outer annular air ducts. The OFA method is characterized in that OFA is fed to the OFA nozzles, and the OFA volume accounts for 19%-25% of total volume of air entering the boiler. The efficient low-pollution W-shaped flame boiler OFA device is simple in structure and can guarantee full mixing of OFA and main stream smoke.

Description

technical field [0001] The invention relates to an overfire air device and method, in particular to a high-efficiency and low-pollution W-shaped flame boiler overfire air device and method. Background technique [0002] W-flame boiler has the following remarkable technical features in terms of combustion: ① pulverized coal particles stay in the furnace for a long time; ② the furnace temperature level is high, which improves the ignition environment and enhances combustion stability. Supplemented by technical measures such as laying guard burning belts, it is beneficial to the ignition of low-volatile fuels, the stability of flames and the burnout of fuels. However, due to the high temperature level in the furnace of the W-type flame boiler, a large amount of NOx is generated, and in the "Emission Standard of Air Pollutants for Thermal Power Plants" (GB13223-2011), which was implemented on July 1, 2014, For W type flame boiler NO x The maximum allowable emission concentrati...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to solve the problem that the existing large-capacity (above 600MW) W-type flame boiler burn-out air equipment occupies a large space, has a complex structure, cannot take into account both the incident depth and lateral diffusion capacity, and cannot ensure sufficient mixing of burn-off air and mainstream flue gas. At the same time, it does not affect the combustion organization of the main combustion area, causing inconvenience in construction design and installation, reducing the thermal efficiency of the boiler, increasing the coal consumption of the power plant, and providing a high-efficiency and low-pollution W-type flame boiler burn-off air device and method

Images