Valuable energy of biochar from agricultural and forest waste streams

Wastes from forest and agricultural industry are still insufficiently used. One of the ways of their preprocessing is a pyrolysis process. Therefore, the aim of this study was to determine the energetic properties of biochar made of walnut shells, forest wood chips and willow chips. The studies were performed according to standards. The moisture contents of the material, the ash contents, the net and gross calorific values were determined. Low moisture and ash content were found in each of the biochar species. For all tested samples the ash contents were lower than 6% and for forest wood chips it was 1.5% only. The way of processing the biomass in the pyrolysis process significantly increased the calorific value of the raw materials. It was found that the net calorific values of the tested materials were high and reached the amount of 26.58 MJ‧ kg-1 for biochar made of walnut shells, 22.29 MJ‧ kg-1 for biochar made of forest wood chips and 24.59 MJ‧ kg-1 for biochar made of willow chips. Due to the good physical properties of biochar produced from waste and biological materials, it was found that these solid fuels can be used for energy purposes