掺烧煤质差异较大煤种对“W”火焰炉运行参数的影响

Effect of blending coals with great difference in coal quality on operating parameters of W-flame boiler

针对掺烧煤质差异较大煤种时锅炉运行参数变化不确定的问题,以一台660 MW“W”火焰炉为研究对象、100%热耗率验收工况为锅炉负荷条件,研究在燃用现行煤种义马烟煤(烟煤)的基础上,按照不同比例掺烧金竹山无烟煤(无烟煤)对锅炉运行参数的影响。利用数值模拟得到2种煤化程度差异较大煤种按照不同比例掺烧时,锅炉有效利用热、烟气速度和温度以及NO_(x)、SO_(x)、CO产量的变化情况。模拟结果表明:锅炉在以高负荷运行时,65%无烟煤+35%烟煤的掺烧比例可以提高锅炉使用寿命,降低炉膛受热面发生腐蚀的概率,但对煤粉的着火和稳燃无促进作用;50%无烟煤+50%烟煤的掺烧比例可以满足锅炉额定效率,同时能显著降低发电成本,但炉膛受热面的腐蚀情况会较为严重。

To solve problem of uncertain change of boiler operation parameters when blending coal with great difference in coal quality,by taking a 660 MW W-flame boiler as the research object,the acceptance condition of 100% heat consumption rate as the boiler load condition,the influence of blending Jinzhushan anthracite(anthracite)in different proportions with Yima bituminous coal(bituminous coal,the current coal)on boiler operation parameters is studied.Via numerical simulation,the changes of boiler effective heat utilization,flue gas velocity and temperature,and NO_(x),SO_(x) and CO formation when the two coals are mixed with different proportions are obtained.The results show that,when the boiler runs at high load,the mixed combustion ratio of 65% anthracite and 35% bituminous coal can prolong the service life of the boiler and reduce the probability of corrosion on heating surface of the furnace,but it does not promote the ignition and stable combustion of pulverized coal.The blending ratio of 50% anthracite+50% bituminous coal can meet the rated efficiency of the boiler and significantly reduce the power generation cost,but the corrosion of the furnace heating surface will be more serious.