Development and thermal calculation method of 0-1 mm pulverizing system for powdered coal-circulating fluidized bed boiler
To realize the 0-1 mm coal feeding of the powdered coal-circulating fluidized bed,a 0-1 mm pulverizing system for PC-CFB boiler was developed based on the design and calculation experience of traditional pulverizing system.It was characterized by the use of vertical spindle mill to prepare the powdered coal and the use of gas-solid distributor to separate the powdered coal from exhaust gas,and a backup system was set to ensure the normal fuel supply in case of system failure.The thermal calculation model of the 0-1 mm pulverizing system was proposed,the key technical indicators such as the ventilation volume of the mill,the proportion and temperature of the desiccant were determined,the drying output of the pulverizing system was predicted,and the performance of the 0-1 mm pulverizing system for PC-CFB boiler was analyzed.The results show that keeping the output of the mill and the temperature of the hot air constant and reducing the outlet temperature of the mill within the allowable range of the system can reduce the drying dosage and increase the drying output.For every 1℃reduction in the outlet temperature of the mill,the drying dosage required by the pulverizing system is reduced by about 523 m3/h,and the drying output is increased by about 0.4 t/h.
powdered coal-circulating fluidized bed0-1 mm powdered coalpulverizing systemthermal calculation
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