Direct coal liquefaction reactivity under sulfur’s effect was studied via L9(3) orthogonal experimental design. Pressure,temperature,H2S volume content in H2S/H2,and S/Fe mole ratio were considered as factors while total conversion,oil yield,sulfurcontent of oil,and hydrogen consumption ratio as the target indexes. The sulfur migration mechanism in the reaction was inferredaccording to the results. The following conclusions could be confirmed or inferred from this work:Temperature has a remarkable effect onoil yield. From 420 ℃ to 470 ℃,there’s an average increase of 19.0% in oil yield. H2S plays three roles:hydrogen consumption ratiodecrease,light product (including oil and gas) generation,yet more sulfur content of oil. There is a decrease of 0.3% hydrogenconsumption ratio and an increase of 0.9% sulfur content of oil ranging from 0- 1% H2S volume content. S/Fe mole ratio within thereasonable range can promote oil yield,as 0.8 S/Fe mole ratio achieves a better oil yield than both 0(extra- 7.2%) and 1.6(extra-3.6%). During the processing of DCL,elemental sulfur migrates to THFI mostly,as there’s an extra 2% sulfur content of THFI if onlyelemental sulfur is added in the reaction system. According to the results of the orthogonal experiment,the liquefaction experiments withdifferent S/Fe molar ratios in a pure hydrogen atmosphere,and different H2S volume content in H2S/H2 under a constant 0.4 S/Fe molar ratio were further studied. From the distribution of sulfur in oil and asphaltene,combined with the changes in functional group,and freeradical concentration,the effect mechanism of H2S and elemental sulfur and the migration rule of sulfur in coal liquefaction reaction werededuced. It was indicated that the free radical concentration of THFI is to some extent related to both oil yield and hydrogen consumption.Oil yield shows a peak value at 1.2 S/Fe atomic ratio while the free radical concentration of THFI gets its minimal value. At 0.25% H2Scontent,the hydrogen consumption rises apparently while the free radical concentration of THFI reaches bottom peak. It seems to beeasier for H2S than elemental sulfur to react with the precursor of light products,and promote conversion of heavy fraction to the lightproducts. Only in excessive amounts can elemental sulfur combine with asphaltenes slightly. The common point of H2S and elementalsulfur is that they promote hydrogen supply in the gas phase,but have no obvious effect on the functional groups of asphaltene.

李攀钰(1997—),男,甘肃兰州人,硕士硕士生。E-mail:lipanyu@outlook.com

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LI Panyu,YANG He,LI Yang,et al. Effects of sulfur on direct coal liquefaction and sulfur migration mechanism[J].CleanCoal Technology,2025,31(3):147−155.