DOI: https://doi.org/10.55373/mjchem.v28i4.212

Keywords: Coal, co-firing, rise husk, torrefaction, additives

Abstract

Indonesia remains heavily dependent on coal for electricity generation, resulting in rising greenhouse gas emissions and severe air pollution. Biomass co-firing has been identified as a promising strategy to reduce coal consumption, with rice husk offering significant potential due to its abundance and relatively high calorific value compared to other agricultural residues. However, its energy performance is still below that of coal, requiring further improvement. Two main approaches have been applied to enhance biomass quality, namely pretreatment and additive addition. Pretreatments such as pyrolysis and gasification often face technical and economic challenges, whereas torrefaction is more advantageous because it increases heating value and reduces moisture under moderate conditions with minimal emissions. In parallel, additives such as crude glycerol, sunflower oil, and waste cooking oil have been shown to enhance the calorific value and combustion properties of biomass pellets. Previous studies, however, indicate that neither pretreatment nor additives alone have achieved substantial improvements. Therefore, this study proposes a combined approach, employing torrefaction together with selected additives to optimize rice husk fuel properties. The integration of these methods offers a practical pathway to improve biomass quality, support coal substitution in co-firing systems, and contribute to Indonesia’s transition toward renewable and sustainable energy.