粉煤循环流化床锅炉燃煤的成灰磨耗特性实验研究OA

The ash formation and attrition characteristics of coal are important factors affect-ing the fluidization characteristics and heat and mass transfer performance of circulating fluidized bed(CFB)boilers.The coal samples used in the ash formation and attrition experiments of conventional CFB boilers are obtained by simply screening from 0-10 mm coarse raw coal particles,while the pow-dered coal-circulating fluidized bed CFB(PC-CFB)boiler uses 0‒1 mm powdered coal directly pre-pared by the coal crusher.The mineral composition of powdered coal crushed to 0‒1 mm is different from that of coal simply screened to 0‒1 mm,hence the ash formation and attrition characteristics of the two are different.Consequently,the ash formation and attrition experimental data of conventional CFB boilers may not be applicable to PC-CFB.Therefore,an experimental method of ash formation and attrition characteristics suitable for PC-CFB boilers was proposed.Three kinds of coal samples,Shuozhou bituminous coal,Jiaocheng anthracite,and Honghe lignite,were selected to carry out con-ventional CFB and PC-CFB ash formation and attrition experiments respectively.The ash formation and attrition data of coal samples in the particle size range of 0‒1 mm in the two experimental condi-tions were analyzed and compared,and the chemical composition of ash samples was determined.The results show that there are significant differences in the ash formation and attrition experimental data of the crushed powdered coal and the screened powdered coal of the three coal samples.The mass fraction of coarse particles in the ash of the crushed powdered coal of each coal type is higher than that of the screened powdered coal.The distribution of ash particle size of powdered coal ash cal-culated by the conventional CFB and the PC-CFB ash formation methods tends to be consistent in the range of 0.2 mm‒0.5 mm.However,there is a significant difference at both ends.The fluidization attrition rate constant(Kaf)of the screened powdered coal and the crushed powdered coal is also sig-nificantly different.Therefore,the original conventional CFB ash formation and attrition experiment is no longer applicable,which verifies the necessity of the ash formation and attrition experimental method for the PC-CFB boiler.