燃用福建无烟煤CFB锅炉二次风率和上下二次风比的工业型试验

为研究燃烧福建煤CFB锅炉的最佳经济运行数据,通过对DG75/3.82-11型CFB锅炉进行了工业热态试验,测试二次风率和上下二次风比变化对锅炉运行经济性和环保特性的影响,结果发现:⑴维持过量空气系数和上、下二次风门开度不变,随着二次风率的增加,飞灰含碳量先下降后缓慢上升,炉渣含碳量小幅增加,灰渣比逐步减少且减幅收窄,CO排放浓度先减低再缓慢升高但变化量不大,SO2排放浓度略有升高,NOx排放浓度降低并趋于稳定;⑵保持过量空气系数和二次风率不变,随着上下二次风比的增加,飞灰含碳量先降低后缓慢升高,炉渣含碳量略有上升,灰渣比减少,SO2排放浓度小幅上升,NOx排放浓度降低;⑶过量空气系数较大时,对应的飞灰含碳量和炉渣含碳量较低,灰渣比较小,SO2排放浓度较小,NOx排放浓度较大。试验表明:对于燃用福建无烟煤的CFB锅炉,存在最佳二次风率和最佳上下二次风比,可使飞灰含碳量、炉渣含碳量、灰渣比等参数最佳,CO排放浓度、NOx排放浓度和SO2排放浓度也在合理的范围内。并经运行实践证明:保持二次风率在0.39～0.44、过量空气系数在1.25～1.30、上下二次风比为1.0～1.2之间,CFB锅炉的运行经济性和环保特性均可得到有效的保证。

An Industrial Experimental Research of Secondary Air Rate and the Upper & Lower Secondary Air Ratio in CFB Boiler Burning Fujian-anthracite

An industrial experiment was conducted to test the influence of secondary air rate and the upper ＆lower secondary air ratio on the operation economic and environmental characteristics in one DG75/3.82-11 CFB boiler burning Fujian-anthracite. It was found from the experiment that . （1） When the excess air coefficient and the upper ＆ lower secondary air damper was hold constant, with the increasing of the rate of secondary air, the carbon content in fly ash would decrease at first and then rise slowly, the carbon content in slag would increase a small, the ratio of ash/slag would gradually reduce of rate narrowed, the CO emission would reduce at first and then slowly increase in little change, the SO2 emission concentration would increase slightly, the NOx emission concentration would reduce at first and then tended to keep in a steady level. （2） Maintenance constant of the excess air coefficient and the rate of secondary air,with the growing of the upper ＆ lower secondary air ratio,the carbon content of fly ash would reduce at first and then slowly increase, the carbon content in slag would increase a slight, the ratio of ash/slag would reduce, the SO2 emission concentration would increase a small, the NOx emission concentration would also reduce. （3）When the excess air coefficient was larger,the combustible of fly ash and slag was lower,the ratio of ash/slag and the SO2 emission was smaller,the NOx emission concentration was larger. For those CFB boiler whose fuel was Fujian-anthracite,it was showed from tests that there existed an optimal rate of secondary air and the best upper and lower secondary air ratio, which would make the combustible of ash and the ratio of ash/slag lowest, the emission concentration of CO, SO2 and NOx within reasonable limits. The operation practices had proven to maintain the rate of secondary air within 0.39-0.44,the excess air coefficient between 1.25 to 1. 30 and the upper ＆ lower secondary air ratio within 1.0-1.2,the operation economic and environmental characteristics of CFB boiler could be effectively guarantee.