Оптимизация процесса работы пресс-гранулятора соевой половы

Abstract

To determine the optimal design parameters and modes of operation of the screw-type pelleting press, the authors studied the granulation of soybean chaff fractions pre-crushed to 5 mm with the addition of soybean grains as a binder. The pelleting process was stable at a temperature of the pelleting press barrel of 70…80°С and the temperature of pellets at the exit of 65 to 70°С. Humidity control was carried out in accordance with GOST 13496.3-92, the crumbling of pellets - in accordance with GOST 23513-79, GOST 22834-87. Fifteen experiments were carried out in three repetitions according to the matrix of the orthogonal central composition plan of the second order. The factors of the experiment included the matrix thickness, the moisture content of the raw material and the mass fraction of soybean grains in the raw material. The crumbling of the obtained pellets served as the optimization criterion. Based on the experiment results, an adequate regression equation was obtained. It was established that the smallest percentage of pellet crumbling is observed in the moisture content ranges of raw materials of 50 to 60% and the mass fraction of soybean grinding in raw materials of 15 to 16.5%. With a fi xed value of raw material moisture content, the optimal thickness of the pressing matrix corresponds to the range of 27.5 to 39.0 mm, while the mass fraction of soybean grain in the raw material is 15 to 25%. With a fi xed mass fraction of soybean grain, the optimal values of the pressing matrix thickness range between 30 and 40 mm, the values of the initial moisture content are 40 to 60%. To obtain pellets consisting of pre-crushed and moistened soybean chaff and soybean grains with the crumbling rate of less than 12%, the thickness of the matrix with holes with a diameter of 10 mm should be 30 to 40 mm, the mass fraction of soy in the raw material should correspond to 15 to 16.5%, and the moisture content of raw materials should equal 51 to 60%.