焦炭体系下煤焦油模化物的微波转化

Microwave-assisted conversion of coal-derived tar model compound over coke

为研究焦炭体系下煤焦油转化规律,选择甲苯和苯为焦油模化物,研究微波和常规加热下甲苯和苯催化裂解与CO2重整反应特性。研究表明:微波加热对甲苯和苯的裂解有利,"热点效应"是主要原因;同一工况下,甲苯裂解率高于苯;750℃时甲苯裂解率为92.8%,其后较稳定;增加空速对甲苯和苯的裂解不利,尤其是甲苯;温度从600℃变化到850℃,微波条件下甲苯裂解的氢气选择性增长了17.0%,其增幅低于常规加热;苯裂解反应的氢气选择性不受温度影响,微波和常规加热下分别在97%和94%左右;通入合适比例的CO2可以促进甲苯和苯定向转化合成气,在载气的流量不变下,微波和常规加热下甲苯在CO2/(CO2+N2)体积比为0.4和0.2时达到最佳转化,苯达到最高转化所对应的CO2/(CO2+N2)体积比分别为0.3和0.1;通入CO2还能够提升合成气收率和降低合成气氢碳比。

To study the conversion of coal-derived tar over coke,toluene and benzene were selected as tar model compound,and their behaviors of cracking and reforming by CO2 were investigated,using microwave heating and electrical heating. The results show that microwave heating is favorable for toluene and benzene cracking,mainly contributes to the effect of hot spot. The cracking rate of toluene is significantly higher than that of benzene under the same condition. After temperature reaches to 750 ℃,toluene cracking rate is amounted to 92. 8%,and then it is leveled off. Increasing volumetric hourly space velocity exhibites a negative effect on toluene and benzene cracking,especially for toluene cracking. At the temperature range from 600 ℃ to 850 ℃,the hydrogen selectivity of toluene cracking under microwave heating increases by 17. 0%,which is lower than that under electrical heating. Hydrogen selectivity is almost not affected by temperature in benzene cracking,and its value under microwave heating and electrical heating are maintained at around 97% and 94%,respectively. With an appropriate proportion of CO2 introduces into the reactor,toluene and benzene conversion are both improved. Toluene conversions under microwave heating and electrical heating are optimized with a CO2/（ CO2＋N2） ratio of 0. 4 and 0. 2,respectively. Moreover,syngas yield is promoted and H2/ CO ratio is reduced with the import of CO2.