Biomass is a potential renewable energy source as it is abundantly available and does not cost much. However, some property characteristics, such as high moisture content, low energy yield, and inefficient storage and handling operations, make raw biomass less feasible for utilization. To curtail this limitation, it needs to be pretreated before being converted into an energy-efficient fuel. Torrefaction proves to be one such method of conversion wherein the raw biomass is subjected to a temperature range of 200–300 °C with the medium being limited oxygen or inert such as nitrogen and results in solid biofuels with upgraded physicochemical properties such as higher energy density, lower moisture, higher calorific value, hydrophobic nature, and better grindability. Torrefied biomass may be utilized as an alternative to conventional fuel for different industries (e.g., power, steel, sugar, etc.) and plays a significant role in reducing environmental pollution and dependency on fossil fuels. A lot of research is ongoing on torrefaction to compile this technology globally. Hence, this review paper presents an overview of recent advances in torrefaction technology. In addition, factors governing the torrefaction reaction mechanism and various reactors utilized for torrefaction are discussed in detail, along with environmental and economic aspects of the torrefaction process. Moreover, a technology readiness level (TRL) approach has also been discussed, highlighting the possible scenarios based on the existing setups. Lastly, the potential applications are discussed, thereby concluding this work.
All Science Journal Classification (ASJC) codes
- General Chemical Engineering
- Fuel Technology
- Energy Engineering and Power Technology
- Organic Chemistry