热解焦对生物质焦油催化裂解的影响

EFFECT OF CHAR ON CATALYTIC CRACKING OF TAR FROM BIOMASS GASIFICATION GAS WITH TOLUENE AS A MODEL COMPOUND

在小型固定床反应器上,以甲苯为模型化合物对生物质焦油在热解焦上的催化裂解反应进行了研究。重点考察了裂解温度、热解焦粒径尺寸、气相停留时间和水蒸气的流量对焦油的转化率和裂解气成分的影响。结果表明,高温条件下,热解焦对甲苯的裂解具有明显的催化作用。850℃时,所用的两种热解焦对甲苯的转化率分别达到了92.7%和97.0%,同时发现,较小粒径的热解焦和较长的气相停留时间更有利于甲苯的深度裂解。另外,随着水蒸气流量的增加,甲苯的转化率和气体中CO的产率均增大,但当蒸汽甲苯比(S/T)超过6.1时,继续增加水蒸气的流量,甲苯转化率并无明显地提高。

Experiments of tar cracking on char with toluene as a model compound were performed in an electrically heated tubular flow reactor. Effects of reactor temperature, particle size of char, residence time and mass flow rate of steam on conversion of toluene in addition to gas composition were investigated. The results indicated that char has a prominently catalytic effect on conversion of toluene in a temperature range of 650℃ - 850℃. Conversion of toluene on two types of char tested at 850℃ was 92.7 % and 97 % respectively. Experimental data also showed that an increase in conversion of toluene was obtained when decreasing particle diameter of char and increasing residence time of gas phase. Moreover, concentration of carbon monoxide as well as conversion of toluene increases with higher steam content in gas . When steam to toluene ratio （ S/ T） 〉 6.1, increasing steam content has little impact on conversion of toluene.