热解条件对西湾煤与秸秆流化床加压共热解的影响

Effects of Pyrolysis Conditions on Pressurized Co-pyrolysis of Xiwan Coal and Wheat Straw in Fluidized Bed

在流化床加压热解装置中考察温度、压力、气氛和生物质掺混比等条件对西湾煤与秸秆共热解特性的影响,结果表明:在600℃,0.3 MPa,100%N_(2)气氛条件下,随着生物质掺混比增加,共热解油产率先增加后降低,实验值均大于计算值;当生物质掺混比为30%(质量分数)时,共热解油的实验值达到最大(16.90%),高于计算值(13.05%);热解压力由常压升至1.0 MPa时,受高氢分压作用下较多的氢分子参与自由基的加氢饱和作用,共热解油产率先增加后降低,在0.3 MPa时共热解油产率达到最大(17.90%);100%(体积分数,下同)N_(2),100%CO_(2)和50%CO_(2)+50%H_(2)气氛下的共热解油产率分别为16.73%,16.55%和16.07%;与焦油相比,共热解油的密度变化不大,在元素中碳的质量分数由79.32%降低至71.80%,硫的质量分数由0.60%降低至0.31%,n(H)/n(C)增加;共热解油中脂肪烃、芳香烃和含氧化合物的质量分数降低,酚类组分的质量分数增加,三环及以上的多环产物裂解为小分子化合物,油品质量得到改善。

The effects of the temperature,the pressure,the atmosphere,the biomass blend ratio and other operation conditions on the co-pyrolysis characteristics of Xiwan coal and straw were investigated in a fluidized-bed-pressurized pyrolysis device.The results show that under the conditions of 600℃,0.3 MPa,and 100%(volume fraction)N_(2) atmosphere,with the increasing biomass blend ratio,the co-pyrolysis oil yield increases first and then decreases,and the experimentally measured yields are all larger than the theoretical values.When the blend ratio is 30%(mass fraction),the obtained oil yield reaches the maximum value of 16.90%,which is higher than the theoretical yield of 13.05%.When the pyrolysis pressure increases from the atmospheric pressure to 1.0 MPa,more hydrogen molecules participate in the process of the free radical hydrogenation saturation,and thereby the yield of the co-pyrolysis oil first increases and then decreases.The oil yield would reach the maximum value of 17.90%at 0.3 MPa.In addition,the co-pyrolysis oil yield in the 100%(volume fraction,the same below)CO_(2) atmosphere,the 100%CO_(2) atmosphere and 50%CO_(2)+50%H_(2) atmosphere are 18.90%,18.55%and 18.07%,respectively.Though the density of co-pyrolysis oil is hardly changed in comparison to the tar,the carbon content is reduced from 79.32%to 71.80%,and the sulfur content decreases from 0.60%to 0.31%,and the value of n(H)/n(C)also increases.For the co-pyrolysis oil,the content of the aliphatic hydrocarbons,the aromatic hydrocarbons and oxygen-containing compounds reduces,the content of the phenolic components increases,and the tricyclic and other polycyclic products are cracked into small molecular compounds.Thereby,the quality of the co-pyrolysis oil quality is improved.