Pelletizing properties of corn stalk rind

Abstract

To enhance the value of corn stalk and promote the utilization of corn stalk in pellet fuel, the pelletizing process of corn stalk rind using a flat die pelletizer was studied. A central composite design (CCD) methodology of four factors and five levels was applied to determine the effects of four process variables, i.e., material temperature, moisture content, die hole length-diameter ratio, and spindle speed, on responses such as pellet density and power consumption per ton. The statistical analysis of data was performed using Design-expert software and second-order polynomial models generated after analysis of variance applied for the responses. Using response surface methodology, the optimal range of process variable was obtained as follows: material temperature of 78.7 to 91.1 °C moisture content of 17.6% to 26.9%, die hole length-diameter ratio of 2.62–3.04, and spindle speed of 168.2–210.5 rpm. Under these conditions, the pellet density is over 1.0 g/cm3 and power consumption per ton is below 90 kW · h/t.