Experimental System Design Application And Simulation Study Of Double Screw Cold Pressing For Rapeseed

Rapeseed is one of the four major oil crops in the world,which not only occupies a very important position in agricultural products,but also provides people with abundant edible vegetable oils and vegetable proteins.At present,the way to obtain rapeseed oil is mainly done by double screw pressing.Although the temperature and pressure distribution of a double screw press during rapeseed extraction is a complex issue,it has been studied in depth in recent years with a view to better understanding how it works and how it affects the oil yield of rapeseed.The purpose of this paper is to explore the application of the double screw cold pressing technology for rapeseed by constructing an experimental system and using simulation techniques to analyze the process flow of double screw oil pressing for rapeseed in depth with a view to obtaining more accurate results.First,the experimental platform of double-helical cold pressing was constructed according to the design principles and objectives of the experimental system of doublehelical cold pressing of rapeseed.The effects of rapeseed type,porosity,material moisture content,and spindle speed on oil yield were investigated through specific physical experiments.The study showed that the effects of germ mill gap size on oil yield were significant,while the effects of origin and moisture content and spindle speed were not significant,and the main order of the factors was germ mill gap size > rapeseed origin >rapeseed moisture content > spindle speed.For the SSYZ120/12 double screw oil press,the optimal gin gap was 3,the origin of rapeseed was Guizhou province,the moisture content of the material was 6%,and the optimal spindle speed was 16 r/min.Secondly,in order to obtain the simulation parameters required for the multi-physical field coupling simulation,the following experiments on the basic physical properties of rapeseed were done in this paper: a plunger type pressing experimental device was used to understand the stress-strain relationship through experiments;and the moisture content of rapeseed was measured by a moisture tester;finally,the porosity of rapeseed under different pressing gaps of the embryo mill was determined by the sealing wax method.By using three-dimensional modeling technology,the oil extraction process of the double screw oil press was correlated with complex environmental parameters such as the porosity of the material and the spindle speed of the oil press,and the relationship between these parameters and the oil extraction efficiency of the double screw oil press was analyzed in detail by using the multi-physical field coupling method,and after simulation experiments,the following conclusions were obtained:(1)The stress and flow rate of the oil cake increase significantly during the oil extraction process,and this stress and flow rate show a symmetrical distribution when they are involved.(2)The press screw rotation cycle has a significant effect on the oil flow rate on the surface of the oil cake.In the first quarter of the cycle,oil flow rate showed two sharp fluctuations,but with small wave amplitude,while in the second 3/4 of the cycle,the wave amplitude of oil flow rate slowed down significantly and the wave amplitude became more pronounced.After the data,the proportion of oil produced in the first quarter of the cycle in the total oil output is about 5%,but this proportion increases as the loading speed increases,especially when the flow rate increases,the proportion of the two small fluctuations also increases accordingly,while the oil output rate decreases accordingly.(3)The oil yield of the oil press is affected by both the porosity of the material and the spindle speed,with the change of the germ roller gap being particularly obvious.When the embryo mill gap reaches 3,the oil yield will drop sharply;the highest value of the press screw speed is 16r/min,while the oil yield beyond this value will fluctuate at a relatively low level.The highest oil yield of the gin mill reached 84.65% and it had a gap size of only3 and a rotational speed of 16r/min.