Experimental Study On Air Distribution System Of A Supercritical Boiler

At present,the secondary air regulation of utility boilers mostly depends on the experience of the operation workers.This air distribution method has no real scientific basis,which will lead to unreasonable distribution of air and lead to the waste of fuel.It is well known that it is imperative to explore reasonable boiler air distribution methods.Reasonable air distribution method will provide reasonable basis for the operation of power station.There are two kinds of unreasonable boiler air distribution: First,too much air distribution of boiler.Too much air distribution will lower the furnace combustion temperature and increase the heat loss due to exhaust gas,reducing boiler thermal efficiency;the second is that the boiler has too little air distribution and too little air distribution leads to too little oxygen content in the furnace.Although the pulverized coal has reached the point of ignition,it cannot be completely burned,thus resulting in the loss of heat of incomplete combustion of machinery,which leads to the increase of sulfides and nitrogen compounds in the furnace and more air pollution.In this paper,taking 350 MW supercritical boiler of a power plant as the research object,in order to explore the best air distribution scheme,a set of complete air distribution test bench is built according to the principle of similarity.The test is the model test of the cold state test of the power plant.The draught fan? the bellows and the air duct size are based on the principle of similarity.According to the test rules,the resistance coefficient and the flow distribution law of the air duct are measured respectively.The specific air distribution data are obtained through the test and two key parameters are obtained after processing the data: first,the resistance coefficient and the variation curve of the resistance coefficient with the opening of the air valve are obtained.The resistance coefficient curve not only plays a guiding role in manual control of wind doors in small power plants,but also plays a vital role in the programming of modern automatic control valves.Secondly,the flow distribution law is obtained.The flow distribution law of each air duct is a difficult problem in the air distribution system,and the flow distribution law plays a guiding role in the design of the air distribution control system.It has a much functional significance.