污泥与煤在循环流化床锅炉中混烧不仅能实现其减量化处置，还可以作为替代燃料减少煤炭用量，实现资源化利用。在0.3 MWth循环流化床中试装置上考察不同掺烧比例，一、二次风比例，过量空气系数等操作参数对城市生活污泥和徐州烟煤燃烧效率、气态污染物排放的影响规律，重点讨论了煤与污泥中氮、硫的赋存形态及其转化特性，分析了煤与污泥掺烧过程中飞灰组分及熔融特性。XPS结果表明，污泥中N主要以吡咯氮(90.58%)和季氮(9.42%)形式存在，烟煤中N主要以吡咯氮的形式存在；污泥中S主要以有机硫化物形式存在，而烟煤中S主要以稳定的无机硫酸盐形式存在；掺烧过程中，随污泥掺烧比例增加，烟气中CO体积分数升高，NO体积分数显著降低，SO2体积分数略升高；二次风比例增大，NO质量浓度降低，但对SO2基本无影响；过量空气系数由1.2增至1.4，NO与SO2质量浓度随之增加，CO质量浓度降低；污泥掺烧比例由0增至100%时，飞灰含碳量由8.09%增至28.26%，燃烧效率由99.23%降到87.76%。相对于煤单烧，掺烧污泥降低了飞灰熔融温度。

Co-combustion of sludge and coal in circulating fluidized bed (CFB) boilers can not only realize its reduction disposal,but also be used as alternative fuel to reduce the use of coal and realize resource utilization. The effects of operating parameters such as different blending ratio,primary air ratio,and excess air ratio on the combustion efficiency and gaseous pollutant emission of municipal sewage sludge and Xuzhou bituminous coal were investigated on a 0.3 MWth circulating fluidized bed pilot plant. The existing forms and transformation characteristics of nitrogen and sulfur in coal and sludge were discussed,and the components and melting characteristics of fly ash in the process of co-combustion of coal and sludge were analyzed. The XPS results indicate that N mainly exists in the form of pyrrole nitrogen (90.58%) and quaternary nitrogen (9.42%) in sludge. In the bituminous coal,N mainly exists in the form of pyrrole nitrogen. The S in sludge is mainly organic sulfide，while S in bituminous coal mainly is the stable inorganic sulfate. The NO emission decreases while the SO2 emission increases when the proportion of sludge increases during the co-combustion process. The NO emission decreases but barely influence SO2 emission with increasing the secondary air ratio. The NO and SO2 emissions increase while the CO emission decreases when the excess air ratio increases from 1.2 to 1.4. When the proportion of sewage sludge increases from 0 to 100%,the unburned carbon in fly ash increases from 8.09% to 28.26%,while the combustion efficiency decreases from 99.23% to 87.76%. Co-combustion sludge with coal can also decrease the melting temperature of fly ash.

0 引言

1 试验

   1.1 试验系统

   1.2 试验样品

   1.3 试验工况

2 结果与讨论

   2.1 掺烧比例对气态污染物排放的影响

   2.2 一次风比例对气态污染物排放的影响

   2.3 过量空气系数对气态污染物质量浓度的影响

   2.4 掺烧比例对燃烧效率的影响

   2.5 掺烧比例对飞灰组分及熔融性的影响

3 结论