Study On Moderate Direct Coal Liquefaction Process

Direct coal liquefaction is one of effective ways that can solve the problems of global oil shortage and security of energy supplies. Nowadays, improving the reactivity of coal liquefaction, mitigating liquefaction conditions and increasing oil yield have become research hotspots in the fields of direct coal liquefaction. This paper, under the condition of low pressure, studied liquefaction properties of Shenfu coal in intermittent high-pressure reactor. What was investigated was the effect of temperature, time, catalyst consumption, solvent coal ration and hydrogen donor solvent on direct liquefaction properties of Shenfu coal. In addition, the single-component catalyst and the catalyst prepared by impregnation and in-situ load were also compared.The results showed that with the increase of reaction temperature, the conversation ratio of raw coal was unceasingly increasing. The conversation ratio improved from 40.3 % to 48.4 % with the temperature increased from 380℃to 440℃, which indicated the temperature had a significant effect on conversation ratio. At the temperature of 430℃, total conversation ratio, oil and gas yields and asphaltene were 47.6 %, 24.9 % and 22.7 % respectively. At 60 minutes of reaction, total conversation ratio and oil and gas yields, with the increasing of reaction time, reached to 47.9 % and 27.5 % respectively. The consumption of asphaltene, which increased first and then decreased, reached the maximum of 23.2 %. Solvent coal ratio on coal conversion was more obvious; when solvent coal ration increased to 7:1, conversation ratio reached to 53.4 % without catalyst. Catalyst on the conversion of coal is a significant and reached to 63.7 % with 2 % catalyst. From the investigation of different solvents, at low pressure, the decalin had a low conversation ratio which was 15.2 % as solvent, but conversation can reach to 63.7 % by using tetrahydronaphthalene as solvent. In addition, the fraction of 230℃~ 300℃in coal tar as solvent had positive effect on conversation ratio.The single-component catalyst effect was worst when compared with the catalyst prepared by in-situ load and the catalyst prepared by impregnation. The catalyst prepared by in-situ of the same kind with different methods is better than by impregnation. As for Shenfu coal, Fe catalyst was better than Mo, Co and Ni. After Fe and Mo were mixed together, the catalyst effect was superior to Fe, but played a minor role in rising conversation ratio.