Thermochemical Conversion of Biomass for Charcoal Production

Thermochemical conversion of biomass harnesses heat‐driven reactions—principally pyrolysis and carbonisation—to transform lignocellulosic feedstocks into charcoal. In slow pyrolysis processes, biomass is heated under oxygen‐limited conditions (typically 300–700 °C) within kilns, retorts or continuous reactors. Reaction parameters such as peak temperature, heating rate and residence time dictate the distribution of products: a solid char rich in fixed carbon, condensable bio-oil and combustible gases. Charcoal yield and quality depend on feedstock composition, moisture content and reactor design. High‐lignin materials tend to afford greater carbon recovery, while reactor innovations—such as autothermal pyrolysis units—seek to optimise energy self-sufficiency. The resultant charcoal exhibits properties of interest across sectors: elevated calorific value for cooking and heating, sufficient mechanical strength for transport and handling, and tailored porosity for use as a reductant in metallurgical processes or as a soil amendment. Globally, charcoal production from residual biomass addresses sustainable energy access, circular waste management and decarbonisation of industrial thermal processes. Key challenges remain in standardising product quality, reducing emissions from traditional kilns, and scaling up advanced reactors to deliver consistent yields in varied socio-economic contexts.

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Thermochemical Conversion of Biomass for Charcoal Production publication trend

The graph below shows the total number of articles in thermochemical conversion of biomass for charcoal production across all publications each year (not limited to Nature Index journals).

Technical terms

Thermochemical conversion: Heat-driven transformation of biomass under controlled oxygen conditions to yield solid char, liquid and gaseous products.

Pyrolysis: Decomposition of organic material at elevated temperatures (typically 300–700 °C) in the absence or limitation of oxygen.

Carbonisation: A subset of pyrolysis focused on maximising solid char production by limiting volatiles.

Biochar: Carbon-rich solid product of biomass pyrolysis, valued for fuel, soil amendment or metallurgical reductant applications.

Fixed carbon: Fraction of carbon in char remaining after release of volatile compounds, indicative of energy content and reductive potential.

Gravimetric yield: Mass of char produced expressed as a percentage of the original biomass mass.

References

1. Mechanical strength characterisation of pyrolysis biochar from woody biomass. Energy (2023).
2. Char fuel production in developing countries – A review of urban biowaste carbonization. Renewable and Sustainable Energy Reviews (2016).
3. Charcoal as an Alternative Reductant in Ferroalloy Production: A Review. Processes (2020).
4. Biomass Pyrolysis Solids as Reducing Agents: Comparison with Commercial Reducing Agents. Materials (2015).