降低燃用福建无烟煤循环流化床锅炉飞灰含碳量浅谈

煤质特性、燃料颗粒、总体设计和运行工况是影响福建无烟煤在循环流化床锅炉中燃尽的主要因素。结合2台燃用福建无烟煤的DG75/3.82-11型CFB锅炉的运行情况,采取一系列有利于福建无烟煤在CFB锅炉中燃尽的措施:改善燃料粒径配比,采用窄筛分偏粗颗粒入炉煤;炉床温度控制在960~1 020℃,整个炉膛维持均衡的高温;改造回料风系统,减少或避免返料偏流,改善燃烧状况;改造二次风机和二次风喷嘴,提高二次风速,增强二次风的扰动穿透能力;优化运行调节,控制风煤配比,维持煤器后烟气含氧量在4%左右,一次风率在55%~60%、上下层二次风比为55:45~60:40,维持恰当的料层高度,一次风室压力控制在10~11kPa,达到较佳的燃尽效果。运行实践证明,这些措施可有效地降低飞灰含碳量。

Disscussion on the Reduction of Fly Ash Carbon Content in Fujian-anthracite-fired CFB Boiler

Coal characteristic ,fuel particle ,general design and operation condition are the main factors to affect the overfiring of Fujian anthracite in CFB boiler. Combined with the operation of two DG75/3.82 - 11 type CFB boilers fired Fujian anthracite, adopt measures which are propitious to the over firing of Fujian anthracite in CFB boiler; improve the matching of fuel particle diameter by using narrow screen ; bed temperature should be controIed between 960 to 1 020 ℃ and balanced high temperature should be kept in the whole furnanee ; rebuild the feed back air system to reduce or avoid revert deflection and improve conbustion condition; rebuild secondary air fan and nozzle, to increase secondary air speed and its disturbance penetration capacity;optimize operation control, control air - coal match,to maintain oxygen content in the flue gas around 4% ,primary air rate is 55% -60%, ssecondary air rate of upper and loer layer is 55：45 - 60：40, maintain proper bed material height, pressure of primary air chamber is kept in 10 - 11 kPa to achieve better overfiring result. The operation practice proves that these measure can reduce carbon content in the fly ash effectively.