The Pressing Experiments And Multi-physical Field Simulations Of Oleander Seeds

Tung oil is one of the four major woody oil tree species in China.Tung oil obtained from its seeds is widely used in industry and manufacturing,and has high economic value.In order to investigate the deformation of the oil cake and the flow state of the oil in the pressing process of the double screw press,and to further understand the factors influencing the oil yield of the oil tung seeds in the pressing process of the double screw press,this paper takes the hulled oil tung seeds in the pressing process as the research object.In this paper,a simulation study was conducted to investigate the double screw oil extraction process of hulled oil seeds using oil cake.Firstly,in order to establish a reasonable physical model,the parameters required to model the oilcake are obtained through the plunger pressing experiment,including the solid mechanical properties and porous media properties reflected by the oilcake during the pressing process.In this paper,the Kawakita equation was used to fit the stress-strain relationship of the oil cake during the pressing process,and the porosity of the oil cake under different stresses was determined by the sealing wax method to fit the porosity vs.stress curve.After that,the accuracy of the simulation model was verified by simulating the side limit plunger pressing experiment with the experimental data of the plunger pressing experiment,and the influence of loading rate and cake thickness on the oil extraction by plunger was also investigated.Finally,according to the oil cake model established above to simulate the oil extraction process of the double screw press,to study the influence of two factors,the cake thickness of the oil material and the speed of the press screw on the oil yield of the double screw press,the experimental results show that.(1)During the oil extraction process,the stress and flow rate gradually increased as the oil cake was gradually rolled into the gap of the press screw,and the stress and flow rate reached the maximum and showed symmetric distribution after being rolled.(2)The flow rate and time through the outer surface of the oil cake showed periodic changes,with two fluctuations in the first quarter of the screw revolution cycle,which were fast and with small peaks,and two fluctuations in the second three-quarters of the screw revolution cycle,which were slow and with large peaks.The oil yield was found that the oil yield from the two small peaks in the first quarter accounted for about 5% of the total oil yield,and the proportion varied with the loading speed,which roughly showed that the flow rate increased and the proportion of the two small fluctuations increased,which also led to a decrease in oil yield.(3)The oil cake material thickness of dehulled oil tungsten seeds and the speed of the press screw both had an effect on the oil yield,with the material thickness of the oil cake having a more significant effect.The oil cake material thickness increased after 21 mm,and the oil yield decreased after the material thickness increased;there was a maximum oil yield speed of 30 r/min,and the oil yield above or below this speed fluctuated around a lower value.The highest oil yield is 51%,corresponding to a material thickness of 21 mm and a rotational speed of 30r/min.