Effect Of Ultrasound On The Solvent Extraction Of Oilseeds And Cakes

摘要

Oil seeds play a significant role in human diet as well as animal feeds and occupy an important position in Indian agriculture economy. They are cultivated on about 25 million hectares producing about 10% of world's total output. Solvent extraction of oil seeds and cakes using hexane is a well-established industry. Plants are designed to suit several types of oil seeds and cakes with different characteristics of porosity and diffusivity. The most common method of extraction is leaching the suitably processed cake with hexane on a moving bed reactor through a multistage crosscurrent extraction. Usually, the residence time of the seed cake in a cross current reactor is 5 to 6 hours. Gommercial plants operate from 30-40 tpd capacities to several hundred tpd of raw material. The relative long residence time decreases throughput and hence the capacity, necessitating huge capital investment. The extraction of oils is rate controlled by diffusion phenomena and extraction depends considerably on the extent to which the internal barriers to diffusion have been overcome. Enhancement of chemical and physical reaction rates under influence of ultrasound is a well-known phenomenon. Application of ultrasound in solid liquid extraction has shown that in some cases drastic increase in extraction rate occurs, while in others only a small improvement takes place. The objective of the present investigation is to study the influence of ultrasound for improving the leaching efficiency of oil seeds and cakes with hexane. We present here our work on extraction under sonication of some oil seeds such as simarouba glauca, groundnut, soybean flakes, ambrette flakes and a few commercially available oil seed cakes. An overall view of effect of ultrasonics in organic solvents is also presented.