Research Of Effects Of Refractory Belt Arrangements On The 300MW Coal-fired Boiler Operation

At present, the proportion of inferior coal reached more than half of coal resources that has been found in our country. In quite a long time in the foreseeable, burning inferior coal is a situation that a lot of power station boilers in our country necessarily need often to face, and in the process of most of the power plants using inferior coal and blended coal as fuel, it often appear some problems like combustion instability and high carbon content in fly ash and slag in the operation of the boiler due to fuel properties deviate from the design value. In order to solve this problem, researchers have proposed some stable combustion program, such as adopting new type burner, changing the way of air distribution, and super fineness of solid fuel combustion, etc. But these methods all have larger workload in reconstruction in the process of practical application, and operation and regulation are more complex.Among all the efforts for improving stable combustion of inferior coal, the application of refractory belt technology is more widely used because the effect of refractory belt on the combustion stability is very obvious. The heat exchange between the local water wall and fire can be isolated, and furnace temperature level increases which is good for ignition of anthracite and lean coal, and high flue gas temperature can also improve superheat steam temperature and reheat steam temperature.But when the installation way of refractory belt is improper, negative effect also is obvious: either combustion unstability or slagging on the surface of refractory belt, when serious slagging appears, the dropping of a large amount of clinker will bring serious test for safe operation of boiler. Many power plants are equipped with refractory belt in our country, but in actual operation, the arrangement of refractory belt and the actual coal do not match, which cause stable-combustion ability is not strong, or the phenomenon such as deterioration of coking chamber of a furnace appears. Therefore, the domestic many power plants have a pressing need for arrangement optimization of refractory belt.This paper improves the problems of the low reheat steam temperature, unstable combustion, high fly ash carbon content for a certain tangential boiler for adopting non-design coal in the operation by laying refractory belt. In order to determine the furnace refractory belt arrangement more reasonably, analyzes the impact on boiler operation of different refractory belt arrangements by numerical simulation. Contrast the affect of the various refractory belt arrangement to optimize refractory belt location and size of the installation. Modified simulation results show that the furnace combustion stability is greatly increased, gas temperature at furnace outlet and superheat steam temperature and reheat steam temperature can achieve the basic design parameters, fly ash carbon content decreases, the boiler efficiency is increased.Research on mechanism of refractory belt stable combustion and influence on combustion stability and furnace temperature optimization of refractory belt arrangement,which has important and positive significance for the improvement of inferior anthracite burning in the economy and the stability of the boiler operation and improvement of the quality of the source network coordination.