Molecular distribution of coal pyrolysis products of bituminous and anthracite from Huainan coalfield by vacuum pyrolysis furnace coupled with mass spectrometer under different electron ionization energies

Bituminous, anthracite and natural coke from Huainan coalfield were investigated by a vacuum pyrolysis furnace coupled with mass spectrometer (MS) directly under different electron ionization (EI) energies.Through total intensity of ions (TII), total number of ion species (TNI), number average molecular weight (Mn), and weight average molecular weight (Mw) of the three coals pyrolysis products, it can be obtained that TNI, Mn and Mw of bituminous pyrolysis products are similar to those of anthracite pyrolysis products, which indicates that the molecular distribution of the bituminous pyrolysis products is similar to anthracite pyrolysis products, but is much different to natural coke pyrolysis products. Through the ratios of specific mass fragment ions of C7H7+/C6H6·+and C4H9+/C6H6·+in the three coals pyrolysis products, it can be obtained that the ratios of C7H7+/C6H6·+ in the three coals pyrolysis products are similar, but that of C4H9+/C6H6·+ in natural coke pyrolysis products is more than the ratio of C4H9+/C6H6·+in the pyrolysis products of bituminous and anthracite, which indicates that the relative content of alkylbenzene to benzene in the three coals pyrolysis products is similar,and that the relative content of aliphatic compounds to benzene in natural coke pyrolysis products is more than that in bituminous and in anthracite.And through all MS data, the proper range of EI energy for coal pyrolysis is from 65 eV to 75 eV.The vacuum pyrolysis furnace coupled with mass spectrometer fleetly can be useful to the quick investigation of molecular distribution characteristics of coal pyrolysis products for coal non-fuel utilization.