Study On Optimization Of Mixed Burning Of Economical Coal In Xuzhou China Resources Power Plant

Due to the impact of supply and demand,the high coal price has greatly challenged the production and operation level and profitability of many power plants.Economic coal is usually high sulfur coal,high ash coal,low calorific value coal,slime and other coal with standard coal unit price advantage,economic coal mixed burning can effectively reduce the cost of power plants,power plants at home and abroad have been widely used.But the mixed burning of economical coal may bring a series of influences to the operation of power plants.For example,when the economic coal is mixed in the power plant,the economic coal is selected improperly,the proportion of mixed coal is unreasonable,and the coal quality characteristics of the mixed coal are not well known,resulting in boiler fire extinguishing,water wall ash and coking,heating surface corrosion,coal breaking in the pulverizing system,burning loss of the burner,boiler efficiency reduction and environmental protection parameters exceeding the standard and other problems.Therefore,the optimization of mixed burning of economical coal is of great research value to every enterprise.Taking 320MW drum boiler of Xuzhou China Resources Power Plant as the research object,this paper studies the influence of economical coal mixing on the safety and economy of the boiler,and puts forward the optimization scheme.First of all,the paper describes the background and significance of economic coal mixed burning.Coal mixed burning is a very important means to reduce the fuel cost of enterprises,relieve the tension of coal supply and improve the profitability of the company.Then from the coal quality characteristics of mixed burning coal,the theory of mixed burning coal is introduced.Then according to the actual situation of coal storage in the coal yard and boiler burning,the paper summarizes the scheme and principle of coal mixed burning in Xuzhou China Resources Power Plant.The thesis mainly analyzes and summarizes the influence of economical coal mixing on boiler equipment and the improvement and adjustment measures.Various adjustment measures and improvement methods are tried to solve the problems in mixed burning of slime coal,high sulfur coal and low volatile coal used for a long time in power plants,and the corresponding solutions and technical reform directions for blending burning of different economic coals are obtained.To control the water content of coal slime to be lower than 12%,it needs to be mixed with coal with good fluidity to add silo.The failure rate of coal breaking in pulverizing system is greatly reduced through the technical transformation of adding rotary coal bucket to original coal silo.Of high sulphur coal and low volatile coal mixing,to adjust the boiler,air distribution mode of secondary air,to slow the high and low temperature corrosion of boiler and the influence of fly ash carbon content on the boiler efficiency,high sulfur coal still need to control charging coal weighted average sulfur content of 1.2%or less,to control for low volatile coal caused by high nitrogen content of coal boiler NO_X levels,etc.Finally,through the mixed burning test of slime and low volatile coal,the site data of mixed burning of economic coal with different ratios are collected,and the optimal mixed burning ratio and optimization scheme of mixed burning of economic coal are determined by using the method of comprehensive consumption difference calculation and analysis and the method of counterbalance method to calculate the boiler efficiency change.Slurry mixing and silo,control the mixing ratio at a low level,the preliminary control ratio is less than 20%,reduce the influence of equipment failure rate on power generation coal consumption.The optimal mixing and burning ratio of low volatile coal and medium calorific value bituminous coal under different loads is as follows:when the rated load is 100%,the ratio of low volatile coal to medium calorific value bituminous coal is 1:1,and the excess air coefficient is 1.142;75%rated load control low volatile coal 1:2 calorific value bituminous coal ratio,excess air coefficient 1.155;50%rated load control low volatile coal 1:3 calorific value bituminous coal ratio,excess air coefficient 1.20.Under the optimal mixing scheme,the burning efficiency of the boiler can be increased by about 1.2%.