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

To study the conversion of coal-derived tar over coke,toluene and benzene were selected as tar model com- pound,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 condi- tion. After temperature reaches to 750 ℃ ,toluene cracking rate is amounted to 92. 8% ,and then it is leveled off. In- creasing 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 al- most 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 heat- ing 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 .