September 15-20, 2019
What differs biochar from charcoal? The simple answer is: Biochar is a carbon rich product obtained from the thermal decomposition of organic material, at the presence of no or a little oxygen. As we can see in principle, the production of biochar is comparable to the production of charcoal, one of the oldest and most established processes used by mankind. While charcoal is made traditionally from wood, biochar can be based on a wide range of biomass and biomass residues.
However, a variety of technologies for the production of biochar was developed in the recent years. The technologies are based on pyrolysis, gasification or hydrothermal carbonization and are ranging from simple up units, like heated steel drums to full automated and controlled processes. Therefore, the obtained products have tremendous differences in its properties and respectively qualities. Not every quality is suitable for further application, or stable or as pure as required.
In literature many options for the application of biochar are described. The most famous one is the use as a soil amendment in agriculture and horticulture. In addition, the application as activated carbon to clean exhaust gases or waste water, as additive in construction industry to improve the insulation or the strength of the construction material or as carrier for catalysts is possible. In most of these cases biochar, its carbon, is sequestered. Depending on the quality, up to thousands of years, in worst case just a few years. Biochar reduces the CO2 in the atmosphere and is therefore CO2-negative, as it saves C as such.
To determine the quality, a comprehensive characterization of the biochar is required. That means the analysis of the chemical composition especially in terms of carbon, hydrogen, oxygen and ash content. While the ash content depends on the feedstock, the process itself influences the C, H and O content, as well as sometimes organic compounds, remaining on the surface of the biochar. Furthermore, the surface structure in terms of surface area, pore volume and pore size distribution as well as the presence of functional groups influences the properties of the char.
To obtain the required quality for each application, the right process is needed. Consequently, it is not enough to only enrich the carbon content by thermal decomposition of organic material. The production of tailor made biochar for specific high added value application is much more complex. If it is done right, biochar can be the solution to overcome problems of climate change. “So for the future of mankind this black matter might give the light at the end of the tunnel”.
Andreas Hornung and Fabian Stenzel, "Biochar - just a black matter is not enough!" in "Bio-Char II: Production, Characterization and Applications", Franco Berruti, Western University, London, Ontario, Canada David Chiaramonti, RE-CORD, University of Firenze, Italy Ondrej Masek, University of Edinburgh, Edinburgh, United Kingdom Manuel Garcia-Perez, Washington State University, USA Eds, ECI Symposium Series, (2019). https://dc.engconfintl.org/biochar_ii/59