Bulk, porous oil-bearing materials acquire various degrees of densification under varying influences of equipment and process parameters with direct bearings on yield during compressive abstraction of oil from such materials. Effects of both aspect ratio and compression cycle on the course of densification were investigated. Mechanical response and oil expression indices were analysed for variances and treatment means were compared using Duncan's multiple range test. All influence factors had significant effects on mechanical response and oil yield. Significant improvements in achievable deformation and specific energy demand were obtained through repeated induction of compressive stress; compression cycle correlated positively with both deformation and energy demand. Margin for the expenditure of energy became wider as pressure ratio at the oil point became lower. This study reveals that performance of compression schemes may be significantly enhanced through careful application of the pressure ratio. ...
