Abstract: Both the geometrical dimensions of die and rations components are the most important parameters influencing on the efficiency of extrusion machine and the quality of pellets.
Therefore, the main objective of the present study is to investigate the influence of geometrical dimensions of die such as; [(L/D) ratio, hole entry diameter (Dhe), percentage of die opening area (OAD), and thickness of die (ThD)] on both the efficiency of extrusion machine and the quality of produced pellets for two different kinds of ration (standard ration, and residual ration) to produce high quality of large animal feed pellets (φ 12 mm).
The extrusion machine with different dies was evaluated for two kinds of ration (standard ration and residual ration) and taken into account the effective design parameters such as; [four levels of L/D ratio (1.42, 1.67, 1.92 and 2.17), hole entry diameter (16, 18 and 20 mm), percentage of die opening area (2.66, 5.33, and 7.99 %), and thickness of die (30 and 35 mm)], while the evaluation parameters were specified into two groups such as; a) machine evaluation parameters (productivity, energy requirements and total losses), b) pellets quality parameters (pellets durability, pellets bulk density, and pellets hardness).
The results indicated that the optimum conditions for producing a good quality of pellets from standard ration were 1.92 L/D ratio, 18 mm hole entry diameter, 5.33 % die opening area, and 30 mm thickness of die, when the evaluated parameters (machine productivity, energy requirements, total losses, pellets durability, pellets bulk density, and pellets hardness) were 0.399 t/ h ., 114.04 kW .h./ton, 5.21%, , 86.72% , 1.190 g/ cm3 , and 184.80 N, respectively.
On the other hand the optimum conditions for producing a good quality of pellets from residual ration were 1.67 L/D ratio, 20 mm hole entry diameter, 2.66 % die opening area, and 35 mm thickness of die, when the evaluated parameters (machine productivity, energy requirements, total losses, pellets durability, pellets bulk density, and pellets hardness) were 0.306 t/ h ., 153.10 kW .h./ton, 5.38%, , 90.35% , 1.11 g/ cm3 , and 192.47 N, respectively.
The multiple regression analysis illustrated that there are empirical equation with highly correlation could be used to predict the evaluated parameters as a function of the studied parameters as follows:
Yi = a + b X1 + c X2 + d X3 + e X4
Where:
Yi = machine productivity, energy requirements, total losses, pellets durability, pellets bulk density, and pellets hardness
Xi = L/D ratio, hole entry diameter (Dhe), percentage of die opening area (OAD), and thickness of die (ThD).
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