The tests with the Kon-Tiki were carried out with the four biomasses spruce wood, spruce bark, rapeseed and wheat straw in a kiln with a diameter of approx. 1150 mm and a height of approx. 520 mm on a grassland site near Aachen. At the beginning of the experiments, a wood chimney was stacked up to about ¾ of the kiln height. For the ignition process the valve for the quench water was opened without connected water pipe, in order to provide air supply from below, and the wood chimney was set on fire with grill igniters. As soon as the time for feeding more material had been reached, the biomass to be investigated was put in the kiln. Shortly before the end of an experiment was reached, the quench water supply was started via the ground connection to stop the degassing process. At the same time, the layers above are to be activated by the rising water vapour, i.e. the pore surface is to be further enlarged if possible. The top carbonized biomass layer was finally extinguished with water from above. The quench water and biochar mixture was left in the Kon-Tiki for about 24 hours. Then the water was drained and samples were taken to determine pH and electrical conductivity. The biochar was separated from the starting material in order to get a better result for the approximate solid yield and the proximate and elemental analysis.
The project ABC4Soil is made possible through financial support from FACCE SURPLUS (Sustainable and Resilient agriculture for food and non-food systems), an ERA-net co-fund. We are thankful for this opportunity and appreciate the support from our funding agencies, the German Federal Ministry of Education and Research, the Research Council of Norway and PTJ Jülich.