THE EFFECT OF SOLVENT COMPOSITION ON PRODUCT YIELDS AND TRACE-ELEMENT CONCENTRATIONS DURING COAL-LIQUEFACTION

The effect of the solvent composition, with particular reference to the saturates content, on product yields and trace element concentrations in the filtered extract solution, produced in the first stage of liquefaction, has been studied. It was found that with up to 14% saturates in the solvent, conversions were of the same order of magnitude, with a possible maximum at 12% saturates. Above 14% the conversion quickly reduced. Preasphaltene and oil levels were found to generally increase with conversion, but asphaltenes decreased. Trace element levels in the filtered extract solution decreased overall, from an ash level of 364 ppm using a solvent with 8% saturates, to 209 ppm with 18% saturates. Most of the individual trace elements decreased in line with the ash level, except for manganese which showed a greater than average decrease, and titanium which, conversely, showed an increase. © 1990.