氧化性气氛下流化床中煤的热解脱硫及硫的分布

兖州（YZ）原煤，在氧气体积分数为3.0%、5.6%、8.7%，热解温度400℃～800℃, 热解停留30min，在流化床反应器中进行了热解脱硫实验。结果表明，兖州煤在3.0%O2，600℃时的脱硫效果最佳，可达70%；此时的黄铁矿硫全部脱除，而有机硫也可脱除60%以上。而相同温度惰性气氛下的总硫和有机硫的脱除率则分别为25%和15%。在氧化性气氛下，脱除的硫主要分布在焦油中；随着氧气体积分数的提高，半焦收率下降的很快，下降幅度要比脱硫率的增加幅度大。因此，氧气体积分数过高，在选择性断裂C—S键的同时，也使C—C键发生了断裂。

Sulfur removal and its distribution during coal pyrolysis in fluidized bed reactor under oxidative atmospheres

Pyrolysis, as a method of pre combustion desulfurization of coal, is an effective approach to control SO2 emission in clean coal utilization. In this study, Yanzhou (YZ) coal was pyrolyzed in a fluidized bed reactor under 3.0%, 5.6% and 8.7% O2 N2 atmospheres and at the temperature range from 400℃ to 800℃. The sulfur distribution in gas and tar product was analyzed. The optimal desulphurization result with 3% O2 N2 atmosphere at 600℃ is reached, during which about 97% pyrite sulfur and 60% organic sulfur are released. However, under N2 atmosphere, at the same temperature, the desulphurization ratio of total sulfur and organic sulfur is only 25% and 15%, respectively. Under the oxidative atmosphere, the most of sulfur in coal is transferred into tar. With increasing the oxygen content of atmosphere, the char yields decrease quickly at high temperature. The decreasing degree of char yield is higher than the increasing degree of desulphurization rate. This suggests that the higher oxygen content would break C—C bonds severely when selectively breaking C—S bonds.