1、Industrial Crops and ProductsVolume 22, Issue 3, November 2005, Pages 207222Oil extraction of oleic sunflower seeds by twin screw extruder: influence of screw configuration and operating conditions I. Amalia Kartika, P.Y. Pontalier, L. Rigal Laboratoire de Chimie Agro-Industrielle, UMR 1010 INRA/INP
2、-ENSIACET, 118 Route de Narbonne, 31077 Toulouse Cedex 4, France Received 8 October 2004. Accepted 6 January 2005. Available online 14 March 2005. http:/dx.doi.org/10.1016/j.indcrop.2005.01.001, How to Cite or Link Using DOI Permissions & ReprintsAbstractThe objective of this study was to investigat
3、e the effects of screw configuration, position of screw elements and spacing between them allowing to realize oil extraction of oleic sunflower seeds on a twin-screw extruder. Experiments were conducted using a co-rotating twin-screw extruder (Model Clextral BC 45, France). Twelve screw profiles wer
4、e examined to define the best performance (oil extraction yield, oil quality, mean residence time, and thermo-mechanical energy input) by studying the influence of operating conditions temperature pressing, screw rotation speed and seed input flow rate.Generally, the position and spacing between two
5、 screw elements affected oil extraction yield. An increase of oil extraction yield was observed when the reversed screw elements were configured with increased spacing between elements or/and with smaller pitch screw. In addition, more oil extraction yield was produced as the temperature pressing, s
6、crew rotation speed and seed input flow rate were decreased. The higher oil extraction yield was obtained under operating conditions 80C, 60rpm and 24kg/h. Furthermore, the operating parameters influenced energy input and mean residence time of matter. Both energy input and mean residence time incre
7、ased when the temperature pressing increased. However, increase of screw rotation speed and seed input flow rate decreased mean residence time. Effect of the operating parameters on oil quality was unimportant. In all experiments tested, the oil quality was very good. The acid value was below 2mgKOH
8、/g of oil and total phosphorus content was very poor, below 40mg/kg.KeywordsTwin-screw extruder; Oleic sunflower; Oil and extraction1. IntroductionIndustrial oil extraction from oleaginous seeds is commonly realized through mechanic pressing with a hydraulic or single expeller press, followed by sol
9、vent extraction. The hydraulic press is most effective but this process is discontinuous. Recently, the application of continuous oil extraction process using extrusion technology gets some attentions from few researchers ( Vadke and Sosulski, 1988, Isobe et al., 1992, Clifford, 2000, Wang and Johns
10、on, 2001, Crowe et al., 2001, Singh et al., 2002andZheng et al., 2003). Extensive studies on extrusion processing of oilseeds using twin-screw extruder to generate oil ( Guyomard, 1994, Bouvier and Guyomard, 1997, Dufaure et al., 1999aandDufaure et al., 1999b) and fatty acid ester (Lacaze et al., 19
11、96) have been successfully carried out too.The continuous oil extraction of oilseeds is widely carried out in a single-screw press. This type of machine consists of a single-screw of variable pitch and channel depth, slowly rotating in a cage type barrel (Isobe et al., 1992). Transport of material i
12、n a single-screw press depends mainly on friction between the material and the barrels inner surface and screw surface during screw rotation. Thus, a solid core component is often necessary to produce the friction. This causes excess frictional heat, large energy consumption and oil deterioration. F
13、urthermore, single-screw presses provide inadequate crushing and mixing if they are not configured with breaker bars or other special equipment. A twin-screw oil press can be expected to solve these problems because of the higher transportation force, similar to a gear pump, and better mixing and cr
14、ushing at the twin-screw interface. In addition, energy consumption of the twin-screw press is more efficient ( Isobe et al., 1992andBouvier and Guyomard, 1997).The preparation of the raw material, such as size reduction, flaking, cooking and moisture preconditioning of the seeds are necessary to im
15、prove single-screw press performance, as well as the mechanical design of the worm and barrel assembly. Maximum pressure increased, and press throughput and residual oil (RO) in presscake decreased, with a reduction in choke opening and with lowering shaft speed of the single-screw press (Vadke and
16、Sosulski, 1988). In addition, when whole seeds or flakes were preheated in the range 40100C, the pressure and press throughput increased and RO decreased. Press throughput and oil output both achieved maximal at canola seed moisture content of 5%, while the RO showed a continuous increase with increasing seed moisture content. Oil recovery of crambe seed extraction on a single-screw press and
