Influence of Binders on Combustion Properties of Biomass Briquettes: A Recent Review

Briquettes are widely used as a renewable energy material for solving the problem of dependency and over-consumption of wood fuel as a source of energy for human use. However, their performance depends on the types and nature of binders used during the preparation and densification process. Most of the performance-related problems such as low yield and energy content can be significantly improved with the use of binders in right proportions. This review discusses the state-of-the-art of fuel briquettes and the influence of binder’s properties on the combustion characteristics, energy content, mechanical durability, and density of fuel briquettes. The compatibility between the binders and the fuel briquettes to obtain a better yield is also discussed with the resulting mechanical and combustion properties. The mechanical durability of fuel briquettes can be improved by reducing the content of lignin, fat, and other extractives in the binder, as well as improving the binder’s variables such as the particle size, texture, and quantity. By using binders mixed with phosphorus-based additives such as Ca(H₂PO₄)₂ and NH₄H₂PO₄ , the combustion rate of fuel briquettes can be enhanced and the pollutant emissions during the combustion process can be reduced to the minimum. In addition, the higher the binders’ compacting pressure and processing temperature, the higher the density and energy content per unit volume of fuel briquettes.