Key technologies for cold pressing of de-hulled double-low rapeseed kernel for oil extraction

It is difficult to extract oil for cold press from de-hulled double-low rapeseed kernel. In order to solve the special technical problems, a structure model with double-stair and multiple-stage compression was given, the structure of pressing chamber of present screw press was improved, and a laboratory-scale cold expeller was designed and manufactured. Effects of operation processing parameters on performance of cold pressing for de-hulled rapeseed kernel ware investigated in the developed press. The results indicate that lower shaft speed (11 r/min) and seed kernel moisture conditioning (6.4% moisture content) are helpful to extract oil from the oilseed, 5.0% hull content in rapeseed kernel is reasonable, maximum barrel temperature is lower than 70℃ which assures production of good quality oil and cake. All those results would pave the way to development of large scale commercially-used expeller.