Study On The Structure Optimization Of Rice Bran Extruder

Rice bran is one of the rice processing byproduct which takes up to 6% of the corn output. China produces 200 million tons of rice every year, so our country produces more than 10 million tons of rice bran every year. Rice bran is a nutrient-rich material, which contains a lot of fats, proteins, vitamins, minerals and other nutritional elements; where fats content reaches 15-20%, and the fats is abundant in oleic acid, lecithin etc. However, fresh rice bran is very easy to rotten due to the effect of the fatty acid and the fats. Therefore the rice bran stabilization technology has become the key of the resource utilization problem. In this paper, the optimization of the rice bran-extruder structure is taken as the major research object, including the liquid evolution character of rice bran and the extruding process technique. The author established the theoretical mathematical model of the transmission rate of rice bran-extruder, then analyzed and optimized the structure of rice bran-extruder.A series of study on the relative theory of rice bran extruding was analyzed at the beginning of the paper. Firstly, the theoretical mathematical model of the transmission rate of rice bran-extruder was built; the theoretical productivity of the extruding rice bran was calculated, and the comparison of theory production and practical production was discussed. Secondly, the study of the evolution of rice bran character revealed that it follows the false-Newton fluid plasticity fluid flow: the apparent viscosity of the rice bran decreases with the increase of sheared rate, the rise of temperature and the increase of humidity. Finally, based on the existing type of extruder, the author analyzed the rice bran extruding process and then got some key factors that affect the degree of the rice bran stabilization.Through the study based on a test, the optimized parameter of the rice bran extruder was found. During the rice bran extruding, the factors in the sequence of affecting the production and SME are the extruder outlet style, the pressure blocks and the kneading blocks. The factors in the sequence of affecting the acid value are the pressure blocks, the kneading blocks and the outlet style. The experiments result indicate that the pressure blocks affect most the rice bran acid value, it plays a larger role in the increase of temperature and shearing rate in the extruder barrel. So it should be put appropriate application in the structure configuration because of their relatively large effect on the output. The kneading blocks can increase the shearing rate and the temperature in the extruder barrel; and it has greater impact on the acid value according to the experimental results, so it should be put more application in the structure configuration. The extruder outlet style is the least factor to affect the acid value of rice bran, but it affects the production most. Thus, in practical applications due to the experiments, the area of outlet style should be increased in order to increase the output.