循环流化床锅炉大比例掺烧煤泥试验研究 -

循环流化床锅炉大比例掺烧煤泥是一种处理煤泥等低品质煤的有效手段。利用一维小室模型对掺混不同比例煤泥的CFB锅炉运行工况进行模拟,研究了掺混煤泥比例对CFB锅炉炉膛内物料平均粒径、颗粒停留时间以及炉膛上部物料浓度的影响,确定了大比例掺烧煤泥条件下的流态优化条件。模拟结果表明,增加煤泥比例可以提高物料循环流率和中间粒径档位(0.1～0.3 mm)颗粒在炉内的停留时间,改善燃料的燃尽率,提高煤泥比例还可以增加炉膛上部的颗粒浓度,有利于提高炉膛上部的传热,降低炉膛温度,便于污染物的控制。根据盘北电厂300 MW循环流化床锅炉机组大比例掺烧煤泥的运行数据,分析了掺烧煤泥比例对床温、排烟温度、底渣与飞灰含碳量的影响。当锅炉负荷为300 MW时,掺烧煤泥后床温明显降低,飞灰含碳量和排烟温度随着掺烧煤泥比例的增加而增大,底渣含碳量则随着掺烧煤泥比例的增加而降低。为了实现大比例掺烧,建议控制矸石的入炉煤粒径,且需要强化尾部吹灰或适当调整尾部受热面。 Large proportion of coal slime co-combustion in CFB boilers is an effective means to treat low quality coal such as coal slime. A one-dimensional chamber model was used to simulate the operating conditions of a CFB boiler with different proportions of coal slime co-combustion. The effects of blended coal slime ratio on the average particle size in CFB boiler furnace,the residence time of particle in furnace and the material concentration of upper furnace were studied,and the optimal operation condition on flow regime under the condition of large proportion of coal slime was determined. The simulation results show that increasing the proportion of coal slime can increase the material circulation flow rate and the residence time of particles in the intermediate size range( 0.1-0.3 mm) in the furnace,and improve the burnout rate of fuel. Increasing the proportion of coal slime can increase the particle concentration of upper furnace,which is beneficial to improve the heat transfer in the upper part of the furnace,reduce the temperature of the furnace,and control pollutants.Based on the operation data of large proportion of coal slime co-combustion in a 300 MW circulating fluidized bed boiler unit in Panbei Power Plant,the effects of proportion of coal slime co-combustion on bed temperature,exhaust gas temperature,carbon content of bottom slag and fly ash were analyzed. When the boiler load is at 300 MW,the bed temperature obviously decreases after the blended coal slime being burned,the carbon content of the fly ash and the smoke exhaust temperature increase with the proportion of blended coal slime increased,and the carbon content of the bottom slag decreases with the proportion of blended coal slime increased. In order to achieve the goal of large proportion of coal slime co-combustion,it is recommended to control the coal particle size of gangue,and it is necessary to strengthen the tail soot blowing or adjust the tail heating surface appropriately