Ultrasonic vibration-assisted pelleting of wheat straw: a predictive model for pellet density using response surface methodology

Background: Cellulosic biomass can be used as the feedstock for liquid biofuel manufacturing. However, high costs associated with transportation and storage of low-density cellulosic biomass has hindered cost-effective manufacturing of cellulosic liquid biofuels. Pelleting can increase biomass density and reduce transportation and storage costs. Results & discussion: This article reports the development of a predictive model, using response surface methodology, for pellet density in ultrasonic vibration-assisted pelleting of wheat straw. The results show that pellet density increases as ultrasonic power and cylinder pressure increase, and as biomass moisture content and particle size decrease. Conclusion: This model can predict the effects of process parameters on pellet density in ultrasonic vibration-assisted pelleting. The methodology can also be applied to investigations of pellet durability and power consumption.