Integrated process of coal pyrolysis with simulated coal gas reforming for tar production

To improve the yield and quality of tar, in this study, the integrated process of coal pyrolysis with simulated coal gas reforming over Ni/Al2O3 (CP-SCGR) was put forward. The results show that the tar yield of pyrolysis in simulated coal gas (CP-SCG) is significantly higher than that in N2 at the same temperature, however, the integrated process CP-SCGR can further improve the tar yield, which is attributed to the radicals, like •H and •CHx, generated from the reforming of SCG over Ni/Al2O3 catalyst. These small molecular radicals combine with coal pyrolysis radicals to retard the polymerization reaction among large radicals from coal cracking. Increasing the contents of CH4 and CO2 and catalyst loading will influence the distribution of pyrolysis products. When CH4/CO2/H2/CO/N2 composition is 4/4/2/1/1, the highest yield of pyrolysis tar is obtained. Simulated distillation and GC/MS analysis showed that the pitch content of the integrated process was reduced and the light tar content was improved, such as benzenes and phenols.