Title:
Assessment of Electricity Generation Potential from Residual Gases of Continuous Wood Carbonization Using a Techno-economic Framework
Author(s):
Santos, P.H.M., Venturini, O.J., Silva Lora, E.E., Rezende, T.T.G., Palacio, J.C.E
Document(s):
Paper
Poster
Abstract:
Brazil is the world's largest producer of charcoal, with production primarily directed toward industrial applications, notably charcoal-based steelmaking. Nevertheless, conventional batch carbonization technologies release substantial amounts of residual gases directly into the atmosphere, resulting in substantial energy losses, air pollution, and environmental degradation, as these gases include significant fractions of methane, carbon monoxide, and carbon dioxide, among others. These losses are mainly associated with the widespread use of large rectangular masonry kilns, which hinder the recovery and utilization of carbonization gases. Such gases contain approximately 50% of the wood's initial energy; thus, given the large production of charcoal in Minas Gerais, they can represent a considerable energy potential for the state. This study evaluates the feasibility of recovering energy from wood carbonization gases using a continuous carbonization reactor ("Lambiotte" type). Owing to continuous operation, this technology enables improved energy utilization through a gas recovery system that supplies part of the carbonization process's energy demand while directing the remaining fraction to electricity generation. The analyzed reactor has a nominal charcoal production capacity of 20 tons/day and provides up to 1.95 MWh of thermal power from residual gases. Electricity generation from the recovered gases was assessed using two conversion technologies: a conventional steam Rankine cycle and an Organic Rankine Cycle (ORC), which achieved electrical efficiencies of 9.5% and 17.7%, respectively. The techno-economic analysis identified the steam Rankine cycle as the most economically viable option under the evaluated conditions, yielding a specific electricity generation of 130 kWh/ton of charcoal for a gravimetric charcoal yield of 33%. For a higher charcoal yield of 42%, the specific electricity generation decreased to 62 kWh/ton. The results demonstrate that continuous carbonization technology is well-suited for large-scale charcoal production in Brazil. In addition to producing superior-quality, homogeneous charcoal, the process enhances overall energy efficiency by converting residual gases into electricity. Furthermore, the controlled combustion of these gases significantly reduces emissions of highly polluting compounds, such as CH4 and CO, thereby mitigating greenhouse gas emissions, particularly methane, which remain among the most critical environmental challenges of the charcoal industry.
Keywords:
charcoal, cogeneration, energy recovery, slow pyrolysis, continuous carbonization
Topic:
Biomass, Bio-based Products and Bioenergy Integration
Subtopic:
Biomass integration into energy systems
Event:
34th European Biomass Conference and Exhibition
Session:
3AV.6.17
Pages:
439 - 450
ISBN:
978-88-89407-27-1
Paper DOI:
10.5071/34thEUBCE2026-3AV.6.17
Price:
FREE
