玉米秸秆炭和木屑炭催化裂解焦油的试验研究

Experimental Study on Catalytic Cracking of Tar with Corn Stalk Charcoal and Sawdust Charcoal

针对生物质热化学转化过程中产生焦油的诸多不利影响,利用催化裂解法将焦其化为小分子燃气,可达到双效降低焦油含量并提高燃气热值的目的。本研究利用500℃条件下慢速热解获得的玉米秸秆炭和木屑炭作为催化剂,在自制的焦油催化裂解装置中,研究裂解温度为700、750、800、850、900、950和1000℃时,两种催化剂对焦油的催化裂解效果。结果表明:两种催化剂对焦油裂解具有良好的催化性能;随着裂解温度升高,裂解气中H_2含量逐渐增加,CO、CH_4、C_2H_4、C_2H_6等含量均逐渐减少,裂解气热值和密度逐渐降低;比较来看,木屑炭对焦油的催化性能优于玉米秸秆炭;焦油裂解产气率随裂解温度升高而增加,在反应温度为1000℃时,玉米秸秆炭和木屑炭催化裂解焦油的产气率分别为91.98%和94.11%。总体来看,玉米秸秆炭和木屑炭既对生物质焦油具有良好的催化性能,又为催化裂解反应提供炭源。

In view of the adverse effects of tar produced in the process of biomass thermochemical conversion, the catalytic cracking method was used to reduce the coke into small molecular fuel gas, so as to achieve the double effects, reduce tar content and increase the low heating value of the producer gas. In this study, corn stalk charcoal and sawdust carbon obtained from slow pyrolysis at 500 ℃ were used as catalysts to study the catalytic cracking effect of tar. The results showed that two kinds of catalysts have good catalytic performance on tar cracking in all runs. As the cracking temperature increased, the content of H2 in the gas increased gradually, the content of CO, CH4, C2H4 and C2H6 were reduced gradually, and the low heating value of the cracking gas density decreased gradually. On comparison, the performance of sawdust charcoal on tar catalytic cracking is better than that of corn straw charcoal. The gas production rate of the cracking was increased with the cracking temperature increased when the cracking reaction temperature was 1000℃ that corn straw charcoal and charcoal were used as catalysts, the gas production rate were 91.98% and 94.11%, respectively. Finally, corn straw charcoal and sawdust charcoal both had good catalytic performance for tar, and also provided carbon source for catalytic cracking reaction.