| Coal is rich in China and used as the main consumption energy in a long term. Compared with traditional pyrolysis, hydropyrolysis is a more effective method to increase tar yield. However, the expensive costs limit its application in industrial production. Methane seems to be a potential alternative material for H2because of its highest H/C ratio and wide range of sources. Nowadays, integrated the process of coal pyrolysis with methane conversion have received widespread attention.In this paper, an new integrated process of coal pyrolysis with steam reforming of methane (SRMP) was studied to improve the yield of tar. The pyrolysis performances of Shuangyashan Coal and the properties of tar under different pyrolysis atmospheres were examined.Pyro lysis results under different atmospheres showed that the yield of tar increased with the temperature in hydropyro lysis and SRMP, and the yield of char decreased. The SRMP process exhibited higher yield of tar obviously under high temperature than those under N2or H2atmosphere.The tar under different pyrolysis atmospheres was analyzed by GC/MS and simulated distillation to understand the change between the tars from pyrolysis process under different atmospheres. The result showed that both the hydropyro lysis and SRMP process can increase the light oil fractions and decrease the fraction of asphaltene in tar. It can be found from GC analysis that pyrolysis atmosphere has slight influence on the benzenes, phenols, naphthalenes, but obviously affects the distribution of its alkyl-substituted homologues from C1to C3.Based on the results by tar analysis, it is thought that the increase of tar yield in SRMP process is related with the stability of radicals from coal pyrolysis. In steam reforming of methane, some small free radicals such as·H,·CH3and CH2are produced, which can combine with the radicals from coal pyrolysis and prevent the condensation between free radicals from pyrolysis, thus improving the tar yield. |
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