Ultrasonic-Vibration Assisted Pelleting for Cellulosic Ethanol Manufacturing: An Experimental Investigation of Power Consumption

Abstract

Ethanol produced from cellulosic biomass is an alternative to petroleum-based transportation fuels. However, its manufacturing costs are too high for cellulosic ethanol to be competitive. Cellulosic feedstocks have low density, causing their transportation and storage expensive, contributing to high manufacturing costs of cellulosic ethanol. Pelleting can increase the density of cellulosic feedstocks and reduce their transportation and storage costs. Ultrasonic vibration-assisted (UV-A) pelleting is a new pelleting method. Effects of input pelleting parameters (ultrasonic power, pelleting pressure, and particle size) on pellet quality and sugar yield have been studied. However, the effects of these parameters on power consumption in UV-A pelleting have not been studied. Since power consumption directly affects ethanol manufacturing costs, lower power consumption is desirable. The objective of this paper is to study effects of different input parameters (biomass material, particle size, ultrasonic power, and pelleting pressure) of UV-A pelleting on power consumption. Four types of biomass materials (big bluestem, corn stover, sorghum stalk, and wheat straw) were studied. Sorghum stalk consumed the least power. Pelleting pressure, particle size and ultrasonic power significantly affected power consumption of all four materials. Higher ultrasonic power and pelleting pressure resulted in lower power consumption. In addition, this paper also compares power consumption between UV-A pelleting and ring-die pelleting (a traditional pelleting method).