| The dominant energy resource of Fujian province is coal,98.3%of which is anthracite.And there are great demands of circulating fluidized bed(CFB)boilers with capacity of lOt/h ed?35t/h burning Fujian-anthracite.However,the combustion efficiency and thermal efficiency of those small capacity CFB boilers in operation is low.To meet the requirements of industrial CFB boiler burning Fujian-anthracite,the author first analysed the combustion characteristics of Fujian-anthracite and existing problems of small CFB boilers burning Fujian-anthracite,and studied main factors influencing these boilers' thermal efficiency.Then based on well-developed methods of CFB boiler design and calculation,probed into existing small CFB boiler design,a new scheme of structure design and parameter selection was proposed.The results of the study mainly included:(1)Increasing the height of furnace chamber by reducing its cross-sectional area and without increasing manufacturing cost;(2)To keep the temperature of furnace chamber around 950? by laying refractory belts on furnace water wall;(3)A cyclone with Separation Efficiency of above 99%is adopted;(4)Reducing fluidization velocities of mass in developed zone;(5)Increased excess air coefficient and optimal ratio of primary air quantity and secondary ones.At last,this method was implemented on a 20t/h CFB boiler burning Fujian Tianhushan-anthracite,and then this boiler had been put into operation in late 2012.Besides,thermal dynamic calculation software for 20t/h CFB boiler is developed using C#programming language to improve the accuracy and efficiency of calculation,because a great amount of parameters are involved in thermal dynamic calculation,even for small capacity CFB boilers,several hundred parameters need to be trial computed in iteration,it takes vast manpower and time,making the calculation complicated.Applying this program,the author has calculated a 20t/h CFB boiler design,and the result indicates that this program can meet engineering needs. |
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