Reaction Kinetics Study on the Heating Stage of the Shenhua Direct Coal Liquefaction Process

Abstract

Direct coal liquefaction in the heating stage of Shenhua Shendong bituminous coal was carried out in a 0.01 t/d continuous tubular facility with iron catalyst and hydrogenated anthracene and wash oil as solvent at a residence time (t) of 3.5–6.5 min and a reaction temperature (T) of 340–450 °C. The results show that when t = 3.5 min and T = 340 °C, a cracking reaction of coal occurs, while the oil yield was almost zero. As the residence time and temperature each increase, coal conversion and product yield exhibit different change patterns. Especially when t = 6.5 min and T = 450 °C: under these conditions, the coal conversion and oil yield reached 83.67 and 52.27 wt %, respectively. To investigate the liquefaction kinetics, a 8-lump reaction kinetic model which follow first-order irreversible reactions (r = ki dC/dt) was developed to estimate the rate constants. The results indicated that the model is perfectly valid for the heating stage, and the yield of oil and gas were mainly from coal other than preasphaltene (PAA).