Experimental Study On Integrated Drying And Classifying Of Particulate Coal In Fluidized Bed

The moisture content in particulate coal has great influence on both combustion and gasification. The lower the moisture content is, the more stable the operation and the lower the energy consumption will be. Therefore, drying process is important for the technology of particulate coal utilization.In this dissertation, the drying and classifying characteristics of particulate coal in internally heated fluidized bed are investigated on the test bench of integrated drying and classifying in fluidized bed.Based on the results of the cold and hot tests, the test bench of integrated drying and classifying in fluidized bed is improved. When the size of particulate coal is within8mm, the bench can operate safely and stably for a long time at the fluidized velocity of0.49m/s and steam temperature of144-155℃.The drying and classifying characteristics of particulte coal in the test bench are studied at different loads. The test bench runs stably at low fluidized velocity of0.37-0.44m/s and average temperatures of81℃,83℃,89℃, and102℃. High vaporization intensity is achieved at high load. The maximum drying capacity is114kg/h and the maximum vaporization intensity is76.7kg/(h·m2). According to the requirements of coal gasification, dried coal with different moisture contents and particle size distribution can be obtained by adjusting the residence time and discharging method.An optimization schemes of the test bench is presented, and the results show that the drying efficiency is higher than22%, when the drying load is higher than90%. The maximum heat efficiency is61%with the maximum load of114%.