Estimation of the yield for coal liquid extracted by supercritical fluids

Abstract Supercritical fluid extraction of a coal liquid was carried out using benzene, toluene and p-xylene at various temperatures and pressures around the critical points of the solvents. The effects of extraction conditions on the extraction yield of coal liquid were investigated, and an empirical equation involving extraction yield as a function of reduced temperature and reduced density was obtained. The equation derived is useful in the estimation of extraction yields of coal liquids in supercritical fluid extraction processes.