Flash hydropyrolysis of northern Chinese coal

Two kinds of northern Chinese coal, Dongshen bituminous coal (DS) and Zalannoer lignite (ZL), were flash-hydropyrolysed in a small entrainment reactor with volatiles residence time (VRT) varying from similar to 2 to similar to 70s. Yields of products were determined for a series of temperatures from 550 to 850 degrees C, with a range of hydrogen pressure from 0.1 to 6.0 MPa. It was found that VRT is an important factor affecting the yield and composition of the FHP product. The appropriate VRT for obtaining hydrocarbon liquids (HCL) and BTX is similar to 42s and the maximum yield of PCX appears at similar to 20s. The secondary hydrogenation of tar is an important intermediate stage for HCL. Temperature and hydrogen pressure exert an important influence on FHP of coal. The HCL yields from DS and ZL are 16.1 and 13.5 wt% respectively at 700 degrees C and 6.0 MPa hydrogen pressure. The optimum temperature for producing HCL and PCX is 700 degrees C. Elevated temperature and hydrogen pressure are favourable for producing CH4. At 800 degrees C and 6.0 MPa hydrogen pressure, the yields of total gaseous product (GP) of DS and ZL are 45.5 and 40.1 wt% and the yields of CH4 are 37.6 and 25.2 wt% respectively. Copyright (C) 1996 Elsevier Science Ltd.