Optimizing the energy intensity of wet granulation of feed in a basket granulator

Wet granulation of plant-based raw materials is necessary to prepare granulated feed of small diameter for fish and their fry. A basket granulator is a feasible solution for this process. The authors performed experimental studiesto establish rational values of factors of wet granulation, providing itslow specific energy intensity. Fish fry feed from plant material was pelleted in a basket granulator to get pellets with a diameter of 2 mm and a length of 4 mm. Three mostsignificant factors affecting the process of wet granulation of plant-based raw materials and specific energy intensity of granulation were established after preliminary studies: moisture content of raw materials, grinding modulus of raw materials and rotation speed of the granulator’s operating parts. Specific energy intensity of granulation was accepted as a criterion for optimizing the wet granulation process of plant-based raw materials. The experiment was conducted at the following values of factors: a feed moisture content of 30, 35, and 40%; its grinding modulus 0.82, 1.24, and 1.66 mm; a rotation speed of granulator operating parts of 40, 50 and 60 min-1. The obtained regression equation adequately describesthe process of wet granulation. The established optimal values ofspecific energy intensity of wet granulation of feeds, equal to 1.9 to 2.3 kW·h·t -1, are achieved at the following rational values of factors: a raw material moisture content of 40 to 42%; a grinding modulus of 1.6 to 1.7 mm; a rotation speed of the granulators operating parts of 60 to 62 min-1. Obtaining waterproof granules at the minimum specific energy intensity of granulation is possible on condition that the specified values of factors are observed.