关键词: 包衣, 冰草种子, EDEM, 正交试验, 工艺参数

Abstract: Aiming at the problems of low pass rate of pelletization, poor mixing uniformity of seed powder, and backward pelletizing process in the pellet coating of Agropyron seeds, this paper adopts the method of combining numerical simulation and experimental verification to analyze the pellet coating technology of Agropyron seeds, among which parameters are optimized. The discrete element software EDEM was used to establish a simulation model of Agropyron seeds, and the dispersion coefficient was used as the evaluation index to study the influence of coating pan inclination, coating pan vibration frequency and coating pan rotation speed on the uniformity of seed powder mixing. At the same time, the pelletization was qualified. The pass rate of pelletization was used as the evaluation index, and single factor test was used to verify the feasibility of numerical simulation. In order to further study the influence of various factors on the uniformity of seed powder mixing, the secondorder regression orthogonal design test was carried out with the qualified rate of pelleting as the evaluation index, and the secondorder regression of the qualified rate of Agropyron seeds pelleting was established through DesignExpert software, with equation and perform analysis of variance. The results showed that the primary and secondary factors that affect the pass rate of Agropyron seed pellets are as follows: coating pan inclination、 vibration frequency、 coating pan rotation speed, and the maximum pass rate of pelletization was used as the optimization objective to obtain the optimal combination of process parameters: the inclination angle of the coating pan was 41°, the vibration frequency was 21 Hz, and the rotation speed of the coating pan was 45 r/min. Under this combination of process parameters, the pass rate of pelletization reached the highest to 95%, which indicated that the best mixing uniformity could be achieved between the seed powders. The research results can provide a reference for the design of pelletizing coating machine for small seeds under vibration and the optimization of pellet coating process parameters.

Key words: pelleting, Agropyron seed, EDEM, orthogonal experiment, technological parameters