The utilization demineralized rice husk waste for biofuel source via pyrolysis: thermogravimetric analysis and kinetic study

Abstract

Rice husk is considered as agricultural waste that causes environmental problem during its handling. In this study, rice husk was treated with acid (citric acid and nitric acid) solutions prior used as raw material for producing biofuel and chemicals via pyrolysis. The pyrolysis behaviors of rice husk treated with water and acid solutions have been investigated through thermogravimetric analysis from room temperature to 600 oC at the heating rate of 10oC/min under 50 ml/min nitrogen flow. Demineralization treatment using strong acid (nitric acid) solution showed more impacts to the rice husk in thermogravimetric analysis, i.e. lower ash content, less minerals content and thermal stability increased. One step model kinetic resulted the lowest activation energy (12.8709 kJ/mol) occured at the 5% nitric acid solution treatment. Excellent agreement between the experimental data and model predictions was found with 8.63% of the relative error. In other words, demineralization using 5% nitric acid solution would improve rice husk performance during its pyrolysis reaction for producing biofuel.

Keywords

• demineralization
• kinetic
• rice husk
• thermogravimetric analysis