| Castor is an important special oil resource. Nowadays, screw pressing is one of the most popular methods of oil separation from oil plant. Study of castor screw pressing and equipment is lack, so that the research on mechanical properties of castor in pressing and influence of the parameters of the screw extrusion process has important theoretical significance and practical value. On the bases of available achievements of non-plug flow conveying theory and plug flow conveying theory, researches have been carried out, which were as follows:1. The related mathematical model of oil transportation segment, the main press section and a section of the cake based on non-plug flow conveying theory and plug flow conveying theory were established. The main parameters affecting transport rates and barrel pressure were analyzed. Based on the advantages and disadvantages of oil pressing of a variety of twin-screw layout form, the most suitable twin-screw layout form was obtained for oil pressing.2. By applying uniaxial press testing apparatus, the experiments of compression ratio-stress and compression ratio-residual oil rate of castor seed were carried out. The prediction model of compression ratio-stress and compression ratio-residual oil rate of castor seed by using of the least square method was developed. The distribution of compression ratio is validated base on the model of compression ratio-residual oil.3. The simulating model of value of oil production and value of energy consumption was developed. Based on the critical pressing point character and by applying the model of compression ratio-stress and compression ratio-residual oil rate, compression ratio of the critical pressing point was solved.4. Combination experiments under several conditions were carried out. The ratio between the actual transport rate and the theory of transport rate was obtained on the basis of plug flow conveying theory. On the basis of plug flow delivery rate model, the equivalent friction coefficient was obtained. 5. Base on spiral squeezing theoretical analysis and experimental research of former three chapters, the outer diameter helix Angle of appropriate value range and the outer diameter helix angle of the screw of each segment of value principle were summarized. A set of twin-screw was respectively designed for complete castor seed and crush castor seed. Combined with the model of pressing chamber pressure and finite element analysis, the core shaft was checked. Base on the advantages of crushed seed pressing, barrel structure of new type twin-screw oil press was put forward. |
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