Effect of Expeller Press Parameters on Fish Oil Extraction

Abstract

An investigation was carried out on the effect of expeller press parameters such as choke clearances (1, 2 and 3 mm), screw clearances (1, 2 and 3 mm) and screw (worm) shaft speeds (50, 60 and 70 rpm) on fish oil extraction. The oil extraction rate and extraction efficiency had a negative relationship with choke clearances and screw clearances but had a positive relationship with screw (worm) shaft speeds. The oil extraction rate and extraction efficiency were found to decrease with increase in choke clearances and also decreased with increase in screw clearances. Increase in screw (worm) shaft speeds from 50 to 70 rpm was observed to increase oil extraction rate and extraction efficiency. The extraction loss had a positive relationship with choke clearances and screw clearances but had a negative relationship with screw (worm) shaft speeds. The extraction loss was found to increase with increase in choke clearances and also increased with increase in screw clearances. Increase in screw (worm) shaft speeds from 50 to 70 rpm was observed to decrease extraction loss. The results obtained from the study of the effects of expeller press parameters on fish oil extraction showed that choke clearance, screw clearance and screw speed influenced oil extraction significantly at 95 % confidence level. The best extraction condition was 1 mm choke clearance, 1mm screw clearance and 70 rpm screw speed, which gave oil extraction rate of 18.91 kg/hr, extraction efficiency of 83.96 % and extraction loss of 5.76 %. The results of this study are useful in optimising the design of presses for fish oil extraction.