Processing high oil content seeds in continuous screw presses

Abstract

This paper covers a range of oilseeds from rapeseed to copra-including groundnuts, cocoa beans, and palmkernels—and gives a very brief definition of screw press operation and its terminology. Screw press operation and its essential similarity to that of the hydraulic stroking press are discussed, including an outline of the functions of the various worm assembly stages and how they are basically achieved and essential objectives which must be met as meal passes along the barrel. Also covered are radial and axial pressure gradients within the machine and their effect on processing of high oil content seeds; rates of pressure buildup within the press and their effect on various different high oil content seeds; and materials of construction. Finally, the effect of seed pre-treatment cooking and fines handling on the operation of a screw press on various seeds and essential differences between high pressure pressing and pre-pressing for solvent extraction are discussed.