Study On Liquefaction Of Shengli Lignite And Its Co-liquefaction With Biomass

Coal direct liquefaction is an important research content of coal clean technology,at present,the co-liquefaction of coal and biomass to produce the oil can make coal and biomass resources efficient and clean utilization,the topic provides some basic research for the develop of coal and biomass liquefaction technology.In this paper,the liquefaction experiments of Shengli lignite(SL)and its co-liquefaction experiments with biomass are carried out with tetralin as solvent and FeS+S as catalyst in a autoclave.The effects of reaction temperature,pressure and gas atmosphere,solvent,catalyst,reaction time and raw material ratio on the liquefaction of coal and liquefied products are investigated,and the thermogravimetric,FTIR and elementary analyses are used to illustrate the structural characteristics of raw materials and preasphaltene(PA)and asphaltene(AS).The experimental results show that the direct liquefaction Shengli lignite is the research object,the suitable conditions for direct liquefaction of Shengli lignite are temperature of400?,reaction time of 60 min,hydrogen pressure of 5MPa,the ratio of solvent/coal 2:1,FeS+S is used as the catalyst,the THF extraction yield and the oil+gas yield reach 66.36% and44.65%,however,the AS yield and PA yield reach 7.3% and 14.41% at this condition,respectively.The THF extraction yield(39.82%)and oil+gas yield(27.44%)without catalyst is the lowest.The suitable conditions for co-liquefaction of Shengli lignite with lignin are temperature of 400 ?,reaction time of 60 min,the ratio of solvent to coal 2:1,hydrogen pressure of 5MPa,The ratio of raw material is 1:1,FeS+S is used as the catalyst,the THF extraction yield and the oil+gas yield reach 84.72% and 64.18%,however,the AS yield and PA yield reach 8.25% and12.29% at this condition,respectively.Compared with the liquefaction of Shengli lignite alone,the co-liquefaction significantly improves the THF extraction yield and oil+gas yield,moreover,the heavy products decrease,which shows the addition of biomass can promote the liquefaction of coal.The results show that THN + H2 O is used as solvent in CO atmosphere,and its liquefaction effect is significant,the THF extraction yield and the oil+gas yield reach57.39% and 44.42%,respectively,compared with H2 atmosphere.The effects of H2 O +formic acid,H2 O + methanol and H2 O + ethanol on the co-liquefaction are investigated,the results show that the THF extraction yield(50.28%)is the highest when H2 O + formic acid is used as solvent,the oil+gas yield(34.8%)is the highest when H2 O + methanol is used as solvent,but the THF extraction yield(38.55%)is the lowest.The effects of the ratio of raw material,the amount of solvent and the type of catalysts on co-liquefaction are also discussed,the results show that the liquefaction effect is different under different reaction conditions,theco-liquefaction is better when formic acid is used as solvent,the THF extraction yield and oil+gas yield reach 87.10% and 62.80%,respectively.