Effect Of Solvent Swelling On The Coal Structure And Liquefaction

The liquefaction of coal has been a research hotspot again for developing a new technology to effectively and cleanly using coal resource. There is a more and more requirement for the monomers of simple aromatics for aromatic engineering plastics with the rapid development of these advanced materials. So there is an opportunity to develop the technology of coal抯 liquefaction. Based on the existence of a majority of one to four rings aromatic stiucture units in coal, the research work was done to develop a method to get aromatics from Zalainuoer lignite and Dal黫ta sub-bituminous coal. The experiments were carried out in a 50m1 micro-autoclave apparatus to investigate the effects of swelling solvent, swelling time, coal sample, catalyst, temperature, and reaction atmosphere on the liquefaction conversion and fraction yields of coal, especially aromatics yield. During the experiment, the raw coal and solvent swollen coal were characterized by SEM,, FT-LB., Temperature-Programmed Theimogravimetiy instrument and adsoiption- desorption scanning instrument. The results indicated that the physical stnicture of coal has been changed during the solvent swelling pretreatment The pyrolytic results show that the solvent swollen coals have much low activation energies than raw coal. The activation energy of DL coal抯 pyridine swollen coal is I 9.99k3/mol, and the activation energy of TRF swollen coal is 23.87kJ/mol, while the activation energy of DL raw coal is 29.66kJImol. Swelling can improve the mobile of the coal抯 small molecule that is rich in hydrogen and be benefit to increase the intrinsic hydrogen donating ability during the following liquefabtion. The swollen coal can get a comparative liquefaction conversion at the initial N2 or H2 atmosphere. The liquefying effect of solvent swelling is more obviously at lower temperature than at high temperature. The swollen coals?intrinsic hydrogen donating ability has been improved. The pyridine swollen coal of ZL coal can obtain higher oil-gas conversion of 58.31% and total conversion of 61.45%, while the TI-IF swollen coal of DL coal has ii obtained a higher aromatic yield of 12.69%. After impregnated with 3wt% A1TM, the DL coal can get oil-gas conversion of 66.17% and aromatic yield of 18.030/o(as the DL raw coal抯 oil-gas conversion of 37.45% and aromatic yield of 9.41%). And after impregnated with Fe2S3 (3wt0/oFe), the DL coal抯 oil-gas conversion is 58.78% and the aromatic yield is 15.02%. Offiei~se, impregnated with catalyst to swollen coal or preU~ated with surfactant before the addition of catalyst both can obtain higher liquefying conversions.