Study On Mechanism And Equipment Of Whole Fat Rapeseed Expanding

In China, rapeseed is a resource of high-quality oil and protein; however the traditional steamed cooked pre-press process not only takes so much time, but also lower protein quality and oil quality of rapeseed meal under the condition of high temperature. For the disadvantages of the traditional rapeseed processing, this issue creatively research on the new process of expanded pre-pressing extraction process by incorporating expanding technology. The effects of different pretreatment (such as flaking, cooking and expanding, etc.) on pressing material character and oil pressing were researched through the micro-structure of rapeseed and the presence of state analysis of rapeseed oil in cells. Based on the research the whole rapeseed oil expansion mechanism is explored. In order to explore the influence of the operational parameters on pre-pressing cake residual oil law, we use the quadratic regression orthogonal design combination with the response surface analysis of rapeseed whole oil expanding specifications.According to the rapeseed main features of high oil content and difficult to establish pressure in the extruder barrel, the rapeseed whole oil expander is designed with increasing of compression ratio, the spiral aspect ratio and so on. It successfully applied to rapeseed expanding pre-pressing industrial production. The major findings of this topic are as follows:1. Transmission electron microscopy observations show that oil material cells are obviously damaged after expanding processing. Oil material is gone through the combined effect of squeezing, kneading, cutting, other mechanical actions and wet heat treatment as well as the moisture flash evaporation effect during expanding process. The tiny lipid droplets accumulate into big oil droplets and were thoroughly exposed outside cells. Meanwhile the combination extent of lipid droplets and protein levels are also significantly reduced. In addition, the porosity inside cells also significantly increased, which are conducive to oil pressed out from material. Thus help reducing the pre-pressed cake residual oil. Those results provide a theoretical support for the new technology of extruded rapeseed oil pre-press process.2. Quadratic orthogonal tests showed that both feeding rate and moisture content of the extruded materials have a very significant effect on residual oil content of pre-press cake, die diameter of the extruded also do effect on content of the residual,but the temperature do not. By frequency analysis, optimization of process parameters range as follows:die hole diameter 9.3～10 mm, puffing temperature of 95.3～98℃, feed rate of 33.6-35.1 t/hr, material moisture content of 8.8%～9.5%. under the parameters of the above mentioned the possibility is 95% for the residue oil content of pre-press cake to be less than 13.5%.3. Combined with the characteristics of rapeseed whole oil expanding, a rapeseed whole oil expander is firstly designed and developed. The expander performance test was done and the following appropriate specifications were determined:(1) the screw length and diameter ratio of 17.77:1; (2) the appropriate lengths and leads of feed section, compression section, quenching section; (3) The number of template holes 39, die hole diameter of 10 mm. 4. Compared the expanding prepressing process and the traditional cooking process in terms of the influence of the quality of each step on its processed material, we found that:(1) the pre-pressed cake lysine loss rate is 34.61% and the expanded material lysine loss rate is 5.94% compare with that of its raw material by expanded pre-pressing process. with the traditional process of 49.04% and 20.79%respectively, it decreased by 14.43% and 14.95%; (2) Expanded pre-press new process from raw materials to pre-pressed cake, the material of the NSI reduced 15.3%,22.4% with the traditional process compared to 7.1% significantly reduced; (3) the phosphorus in crude oil of the new process reduced from more than 500 ppm significantly to below 150 ppm compared with the traditional process.5. The economic indicators were compared with the expanding pre-pressing process and the traditional cooking process based on the industrial production of a 800 t/d rapeseed processing line. production proven that the new process's steam consumption of 157.10 t/d, compared with the traditional process of 202.73 t/d, reducing by 22.51%; new technology power consumption of the 9922.6 kw·h/d, compared with the traditional process 11044.3 kw-h/d, reduced by 10.16%; new process's crude oil yield of 98.18%, improving by 0.5% than the traditional process of 97.68%.