A Study on the Torrefaction of Rice Husk as an Attempt to Enhance Its Energy Content

Abstract

Torrefaction refers to the thermal and chemical treatment of organic substances (at atmospheric pressure, between 200–300°C, under inert conditions). The objective of this study is to torrefy the rice husk of Ethiopian origin, after a pretreatment with dilute sulfuric acid in order to enhance its energy density. The torrefaction temperature, holding time, and acid concentration investigated in this study were (200, 250, and 300°C), (20, 40, and 60 min) and (0.75, 1.50, and 2.25 g/L), respectively. Box-Behnken experimental Design (BBD) was applied for optimization using Design-Expert ® Version 7 software (Stat-Ease Inc., Minnesota, United States).