| The effects of the different solvents and temperature on fractional thermal dissolution（TD）of Xilinguole lignite（XLGL）coal were investigated,and the composition structure of fraction thermal dissolution soluble fraction（TDSF）was analyzed and characterized.Then the influence of temperature,solvent,reaction time and catalyst on hydro-liquefaction of TDSF was probed,and the effect of the catalyst of Ni-Mo-S/γ-Al2O3 on the recycle hydro-liquefaction of TDSF was also investigated.The FTIR,thermogravimetric,elemental and GC-MAS analysis characterized by the products of hydro-liquefaction and catalyst.The following conclusions were obtained.XLGL was fractional thermally dissolved to prepare light and heavy TDSFs,it was found that the TD soluble yield（TDSY）of XLGL increased with the rising of TD temperatures from 320 to 360℃with 1-methylnaphthalene（1-MN）as solvent,and the maximum TDSY of 31.3 was obtained at 360℃,but condensation polymerization became heavy at 380℃.When the polar solvent methanol was added into 1-MN,the total yield of TD was increased from 31.27%to 67.87%.CMNO contained various polar constituents,and it gave the total yield achieved 41.1%at 360℃.FTIR and elemental characterization results showed that the TD process had great effects on mineral ash removal and oxygen content reduction.Theacidityandhydrogenationactivityofcatalystinfluencethe Hydro-liquefaction performance of the TDSF.Compared with no catalyst,catalyst promoted the hydrocracking performance of the TDSF,therefore increasing the total conversion and oil yield of liquefaction.The Ni-Mo-S/γ-Al2O3 catalyst has a good hydro-liquefaction activity on TDSFs.At 360℃and the THN solvent with 1h reaction time,the total conversion and oil yield of hydro-liquefaction were 100%and 52.7%for light TDSF,and 61.5%and 26%for heavy TDSF from 1-MN respectively.The total conversion and oil yield of light TDSF from the 1-MN+10%CH3OH were 95%and 45.1%respectively,which has a great relationship with the molecular structure of the TDSF.Generally,the low degree of aromatic,methyl side chain with more aliphatic structures and the less oxygen-containing functional group were benefit for hydro-liquefaction of TDSF.The oil yield of light TDSF from 1-MN reached 75.2%when the liquefaction temperature was up to 400℃,indicating that the liquefied oil yield of TDSF increased with the rising of TD temperature.The catalytic effect is not increased with the prolonging of reaction time.Hydrogenation and condensation reaction has two forms of competition in the catalytic liquefaction process of TDSF.In a certain period of time,hydrogenation is dominant,and after the condensation reaction gradually increased,leading to the liquefied oil yield decreased.The recycle hydro-liquefaction of light TDSF at 400℃using Ni-Mo-S/γ-Al2O3catalystsuggestedthattheliquefactionperformanceofTDSFfrom1-MN+10%CH3OH solvent,which contained high content of O was bad than the TDSF from 1-MN.The oil yield of light TDSF was 73.7%by use of fresh catalyst,then it decreased to 63.1%and 58.8%by use of the first and third recycle catalyst respectively.According to characterization analysis of products from recycle hydro-liquefaction,it could be found that large number of macromolecular substances were adsorbed on the surface of Ni-Mo-S/γ-Al2O3 catalyst,making the catalyst close to inactivation in the second recycle use.In addition,the GC-MS analysis of the hydrocracking product oil showed that the oil mainly included two benzene ring aromatic hydrocarbons.The saturated cycloalkane content in the liquefied product oil from fresh catalyst reached 19.3%. |
