Coal Liquefaction For Producing Aromatic Hydrocarbons

The investigation is based on macromolecule aromatic structure of coal. Two coals,Zalainuer lignite (abbr. ZL) and Daliuta subbituminous coal (abbr. DL),were used to prepare aromatics and polar compounds through hydroliquefaction process.The experiments were carried out to investigate the effect of temperature,initial H2 pressure and soaking time on conversion,oil+gas yield and aromatics,aliphatics and polar compound yields of ZL and DL coals. The results indicated that the optimum liquefaction conditions are liquefaction temperature of 440,soaking time of SOmin and initial H2 pressure of 6.0MPa;ZL coal has higher conversion and oil+gas yield but less aromatics yield than those of DL coal at the optimum liquefaction conditions.Swelling pretreatment of ZL and DL coal by using pyridine,tetrahydrofuran (THF) and isopropanol solvents was used to investigate its effect on the characteristics of hydroliquefaction of ZL. and DL,and aromatics and polar compounds yields of the two coals. The results indicated that it is possible to break the hydrogen bond in ZL and DL coals by using pyridine and THF solvent swollen pre-treatment. ZL coal has higher conversion and oil yield than those of DL coal by using pyridine and THF swelling pre-treatment at the swelling time of 24h. Swollen DL coal by using THF has higher conversion and oil+gas yield than that by using other swelling agents. The conversion and oil yield of DL coal reach 49.5wt%daf and 46.5wt%daf,respectively;the aromatics and polar compound of DL coal were 12.7wt%daf and 11.8wt%daf,respectively.The effects of dispersion and size of in situ impregnated Fe2S3 catalyst by using Fea(SO4)3 and Na2S as a catalyst precursor were investigated. The changes of conversion,oil+gas and asphaltens yields of DL coal were studied by using in situ impregnated Fe2Sa in water and in a surfactant (Hexadecyltrimethyl ammonium bromide,abbr.1631-Br)solution. In addition,the effects of incipient impregnated ATTM on aromatics and polar compoundyields of DL coal were also investigated. The changes of aromatics and polar compound yields of DL coal before and after loading of FeiSs catalyst in the surfactant solution were emphatically analyzed. The experiments results shown that conversion and oil+gas yield of DL coal with impregnated Fe2S3 in the surfactant increase up to 68.8wt%daf and 59.5wt%daf,respectively;and aromatics and polar compound yields is higher than those of the raw coal,6.9wt%daf and 7.2wt%daf increment,respectively. The data of thermogravimetry analysis by a pressurized thermobalance at Hb atmosphere shown that weight loss of DL coal loading in situ impregnated FeaSs catalyst in the surfactant solution is more than that of DL coal with in situ impregnated Fe2S3 in water and raw coal. The pyrolysis temperature with a maximum weight loss rate of DL coal loading Fe2S3 in the surfactant is 30 lower than that DL raw coal. The results of the experiment also shown the synergistic effect between in situ impregnated FeaS3 and swelling pretreatment by using pyridine and THF solvents on aromatics and polar compound yields of DL coal liquefaction.Fe2 (MoS4)3 and FeMoS4 bimetallic catalyst were prepared,and the effect of those catalysts on conversion,aromatics and polar compound yields of DL coal were investigated. The results indicated that the conversion,aromatics and polar compound yields of DL coal loading of the bimetallic catalyst lwt%daf FeMo were 83.6wt%daf,23.6wt%daf and 18.9wt%daf,respectively,the data are higher than those of the use of Fe2Ss or ATTM catalyst alone.