Energy Assessment of a Slow Pyrolysis Plant for Biochar and Heat Cogeneration

The production of biochar by slow pyrolysis systems is a promising technology to achieve negative emissions. In this paper, an energy analysis model for a biomass-based biochar production plant utilising the slow pyrolysis process is presented. The model was used to evaluate the energy analysis of a plant processing lignocellulosic biomass. The energy analysis considered the main technical parameters of this type of plant, including the moisture content of the biomass, the moisture after drying, the pyrolysis temperature and the characteristics of the biomass. The results showed the heat losses for each component of the plant and the recoverable useful heat from the production process, which represents about 16% of the chemical energy originally contained in the biomass. Although this is a secondary output, this aspect is important for analysing the sustainability of the biochar production chain. The energy analysis enabled by the model presented is indeed a valuable tool for the technical, economic and environmental assessment of biochar production plants.