A Research On Reducing Carbon Content In Fly Ash Of 220t/h Pulverized-Coal-Fuel Boiler

The problem of high carbon content in fly ash can be seen frequently in the Chinese power plant,which due to buring coals of low rank,or the boiler has a low adaptability. High carbon content in fly ash not only lead to great decreas in the economic benefits,but also cause damage to the equipment.So for the power plant ,it makes great sence to find the ways to reduce the amount of combustible matter in fly ash.High carbon content in fly ash means that the coal is not burning well in the boiler.There are many facters which influence the rate of the coal-combustion,such as content of carbon in coal,the caloric power,the specific surface and the interval porosity.The work condition of the coal-feeding system, the aerodynamic field and the structure of the boiler also contribute to the high carbon content in fly ash.This thesis is based on the No.3 boiler of YuanChun power plant of Guangdong province,which was suffering a high carbon content in fly ash.First,we made research on the character of the Guigang coal,which was using as the fuel for a long time. The elemental analysis,technical analysis and the thermo-gravimetric analysis was taken to help us get the datas.At the same time,we made judgements on its ignition and burning-out tendency.As a contradistinction,we also gave researchs on the Shenhua coal and their blends.Though the experiments,we found that the Guigang coal was more difficult in burning-out than the Shenhua coal and their blends.Based on the conclusion,we decided to gave a technological transformation to the boiler.We decided to add buff-bodys near all the end of the lowest primary air spouts,which can improve the combustible condition.Then the horizontal fuel rich-lean burnners were used in the A and B cornner,which can stabilize the burning flame.After the technological transformation,we gave the furnace an aerodynamic field test to check the well-condition of it.Then after several days operation,the data of the amount of combustible matter in fly ash came out to demonstrate the success of the reconstruction,which also make sence to the design and operation of the power plant.