Prediction Method Of Coal Slagging Property In Stoker-fired Boiler

In the process of coal utilization in China,boilers are the main equipment of coal utilization.At present,China is using more than 480,000 coal-fired industrial boilers and 300,000 layered combustion boilers,consuming about 400 million tons of standard coal each year,accounting for about a quarter of China's total coal consumption.The problem of slag formation is more prominent in the operation of layer burning boiler,which will affect the safety and efficiency of operation.At present,the prediction of coking degree of coal mainly depends on the fusibility of ash and the characteristics of crucible coke slag.As the two methods are the experimental data under the conditions of fixed atmosphere and environment,the combustion and pyrolysis process of coal in coal-fired layer combustion boilers is relatively complex,and it is difficult to carry out engineering application by only a few simple indexes.Therefore,this paper selected coal samples in north and east of Shanxi,analyzed their physical and chemical characteristics,studied the relations among various influencing factors,and proposed a slagging prediction method based on fuzzy cluster analysis.The research capacity is as follows:(1)The internal and external factors of coal slagging were explored and the experimental contents were prepared.The moisture,volatile,ash,fixed carbon,carbon,hydrogen,oxygen,nitrogen and heat of 13 kinds of coal were analyzed by industrial analyses and elemental analyses.Their relationships and their influence on slag formation were studied one by one.(2)Using thermogravimetric analyzer,simulated was the coal in the weightlessness of 0-1200? pyrolysis process.The absorption and exothermic process of coal was observed by means of differential scanning calorimetry curves.The rate of weight loss with temperature can be analyzed by their differential curves of thermal weight.The regularity of weight loss and heat variation due to different minerals and eutectic heat absorption and exothermic temperature in coal were determined.(3)The composition and content of minerals in coal were tested by X-ray fluorescence spectrum and X-ray diffraction.Minerals found in coal are usually composed of minerals such as quartz,kaolinite,kaolinite,mica,carbonate,hematite,pyrite and clay.Their contents of the substances were analyze.The deformation temperature,softening temperature,hemispheric temperature and flow temperature of coal were measured by ash fusion point meter,the relationship between melting point,slag characteristics and mineral content of different compounds was compared.The effects of various mineral contents on melting point were analyzed.(4)The internal and external factors influencing slag formation were analyzed to select 12 influencing factors based on the experimental data(ST,?T,CB,Na,G,Si/Al,Fe/Ca.B/A,S,Rf,Cl,MM).13 kinds of coal samples were identified for coking.The factors were coupled while any single factor can't accurately reflect the coking process and the degree of the complex stratified combustion boiler.Based on this,a method combining fuzzy cluster analysis with mineral content is established to predict coal slagging property more accurately.