Optimising the setting parameters of a passive grinder used for rye molasses preparation

Abstract

Grain molasses can compensate the deficiency of easily digestible carbohydrates in a cow’s ration. The best raw material to produce molasses is rye. Molasses can be produced on farms directly before feeding. Today it is highly promising to improve the technology and technical devices for the production of grain molasses. The research was conducted to determine optimum values of adjustment parameters of a passive shredder (the grate angle and the diameter of grate apertures) by estimating their influence on the optimization criterion – specific energy consumption. The author determined quality indicators: the number of whole grains and the residue amount on the sieve with a mesh side size of 3 mm. Whole grains (the “Grafinya” winter rye variety) were crushed with a passive shredder. According to its design, the grate angle is changed from 30 to 90° and the grates have different hole diameters (3, 6, and 9 mm). The author made a matrix of complete factor experiment 3² and obtained an adequate response function. They also evaluated the desirability profile and Pareto plot for the studied factors. At the first stage of the research, it was found that the reduction of specific energy consumption is greatly influenced by increasing the value of the grate aperture diameter. The response surface was plotted and the antigradient of the function was determined. At the second stage, a pitch towards increasing the hole diameter to 9 mm was selected and the planning matrix of the fractional factor experiment was made. An extremum point with the minimum value of the function was defined for the resulting response function. In the natural form, the specific energy cost is 55.56 Wh/kg with a grate angle of 60.6° and a grate hole diameter of 6.57 mm. The values of 60° and 6 mm with specific power inputs being in the area of minimum and amounting to 56.4 Wt-h/kg are recommended as adjustment parameters, which is 1.3 per cent higher than the calculated values.