Integrated coal pyrolysis with methane aromatization over Mo/HZSM-5 for improving tar yield

In this paper, a new process to integrate methane aromatization over Mo/HZSM-5 catalyst with coal pyrolysis was put forward for improving tar yield. Shenmu coal was used to confirm the validity of the process. The effects of pyrolysis temperature, CH4 flow rate, Mo loading on the tar, water and char yields were investigated in an atmospheric fixed-bed reactor containing upper catalyst layer and lower coal layer. The results show that the tar yield can be improved by integrating the coal pyrolysis with methane aromatization. The tar yield is 21.5 wt.% (daf) under the optimum conditions of 700 °C pyrolysis temperature, 25 ml/min CH4 flow rate, 4 wt.% Mo loading and 30 min holding time, obviously higher than 14.6% in N2 atmosphere and 15.3% in H2 atmosphere. Further studies confirm the synergistic effect between the coal pyrolysis and methane aromatization.