Enhancing bio-oil yield extracted from Egyptian castor seeds by using microwave and ultrasonic

Energy scarcity and conventional energy problems are the main reason of finding a renewable source of energy which is cheap and environmental friendly, therefore, biodiesel production is one of the most promising solutions of this problem. Also, Egyptian castor is one of the most important crops for oil production compared with other commonly used oil crops. The main aim of this study is to enhance the production of bio-oil from Egyptian castor seeds by using microwave and ultrasonic as pre-treatments. To achieve that, the effects of extraction screw speed (20, 40 and 60 rpm) and temperature (100, 150, 200 and 250 °C) on oil extraction yield and quality, extraction energy requirements and extraction time and were studied. Also, the effect of pretreatment conditions of microwave at three levels of power (Low, Med and High) and different times (1, 2 and 3 min) and pretreatment condition ultrasonic with different temperatures (40, 60 and 80 °C) and different times (15, 30 and 45 min) for castor seeds before extraction with the optimum condition of the screw press on oil extraction yield from castor seeds, extraction energy, extraction time and quality of the oil extracted. The results indicate that the optimum conditions oil extraction by screw press were 200 °C extraction temperature and 60 rpm screw speed. It could be seen that the extraction oil yield, extraction energy requirements and extraction time were 35.59%, 18.68 and 1.86 min, respectively. Microwave pretreatments had better on oil yield and energy required for extraction compared to ultrasonic pretreatments, where, microwave pretreatments recorded high oil yield and lower energy requirements compared to the ultrasonic pretreatments. Oil yield ranged from 32.67 to 37.41% compared to 13.29 to 39.83% in literature. The time required for extraction was ranged from 1.77 to 2.00 and 1.79 to 2.21 min for microwave and ultrasonic pretreatments, respectively. The pretreatment improved properties of the extracted oil.