Research and application of twin-screw expeller for cold pressing of de-hulled rapeseed

摘要

In order to solve the technical problems of cold pressing of de-hulled double-low rapeseed, a new twin-screw expeller with a principle of combination ofjoggling and non-joggling was designed and manufactured. The pressing chamber had characteristics of multiple-stage compression and relaxation and a thin layer of materials when pressing. Theoretical compressing ratio of the twin-screw expeller is 23.0, and ratio of length and diameter of pressing chamber is 11.5 with a pressing time of 180 seconds. In the twin-screw expeller, materials could be clear intensely so that the problem of de-hulled rapeseed feeding was solved. The twin-screw expeller was applied to cold pressing of de-hulled rapeseed successfully. The oil content of cold pressing cake is reduced to about 15%. Cold pressing oil approaches the standard of the third grade rapeseed pressing oil (Chinese national standard, GB1536-2004). Cold pressing cake temperature is lower than 70°C which assures good quality of oil and cake.Twin-screw expeller is suitable for pressing de-hulled rapeseed with obvious quality improvement of rapeseed oil and reduction of energy consumption, which can increase processing value of double-low rapeseed.