Eight Chinese oil shales were extracted under nonisothermal conditions with supercritical toluene and toluene-tetralin mixtures. Optimum extraction conditions for high liquid yield and high conversion were determined by systematic variation of extraction parameters: pressure
final extraction temperature
oil shale particle size
solvent flow rate
and H-donor content of the solvent. The results indicate that supercritical extraction of oil shale with toluene gives about twice as much oil yield as conventional retorting. With supercritical hydroextraction
where an H-donor is added to the supercritical toluene
nearly complete recovery of organic matters in the oil shale is possible with a high proportion of liquid products. From the concentration of extract in solution at different temperatures
the kinetics of supercritical extraction of oil shale was shown to be first order in rate
divided into two regions
with corresponding activation energies of about 120 and 180 kJ/mol