Development of a transient CFD model for charcoal production in a batch reactor and validation with measurement data

In order to facilitate the development and optimization of a batch reactor for charcoal production, a new CFD model was developed that allows a detailed description of the pyrolysis process of the biomass within the batch reactor. Focusing on computational efficiency, the model is not based on single biomass particles, but on a description of the (local) properties of the packed bed inside the reactor. The drying and pyrolysis processes are described on a local scale, such that according to the prevailing conditions (temperatures, flow) the progress of the reactions can be analysed. To validate the CFD model, dedicated test runs were performed using a pilot-scale pyrolysis reactor, and the measurement results were compared to the simulation. The results show that the progress of conversion is well represented, and a reasonable agreement of temperature profiles inside the retort is achieved. The overall trends for the profile of mass release are also reproduced.