optimization the specific energy consumption in compost manure extrusion process using response surface methodology

densification of biomass material that usually has a low density is proper way to increasing density,reduce transportation cost and simplify storage and distribution of these materials. pellet productionusing extrusion process is a common method for densification. the goal of this research isoptimization of specific energy consumption for extrusion process considering its effect on pelletdensity. compost was extruded into cylindrical pellets utilizing open-end dies under axial stressfrom a vertical piston applied by a hydraulic press. the effects of independent variables, includingthe raw material moisture content (35, 40 and 45% (w.b.)), particles size (0.3, 0.9 and 1.5 mm),speed of piston (2, 6 and10 mm/s), and die length (8, 10 and 12 mm) on specific energyconsumption and pellet density, were determined. the experiments were designed using responsesurface methodology based on box behnken design (bbd) in order to optimize. the resultsrevealed that all independent variables have significant effects on studied responses in this researchat pwere: moisture content between 40-45%, speed of 2 mm/s, particle size from 0.8 to 1 mm and dielengths of 10 to 12 mm.