During gasification and/or pyrolysis of wooden biomass, charcoal is formed as a solid intermediate or product. In CO₂‐ and H₂O‐rich atmospheres at high temperatures, a high specific surface area of several 100 m² per gram of charcoal may be reached. Common biomass gasifiers aim at a charcoal conversion of 100 %. Up to now, the option of a subsequent usage of the charcoal for adsorption of tar compounds has rarely been considered but is an interesting option to produce a clean syngas in a downstream adsorption unit. Experimental studies show an adsorption capacity of up to 0.4 g of tar per gram of charcoal using naphthalene as a model substance for tar. Respective adsorption isotherms, breakthrough curves in a fixed‐bed adsorber, and a kinetic breakthrough model are presented.

In this study, biomass–specific gasification data is experimentally collected for numerical simulations of fixed–bed reactors. Since biomass properties vary, it is crucial to have characteristic biomass data. Extensive data is collected to determine an appropriate description of specific biomass behavior, including basic data (e.g., heating value, size, densities, ultimate and total analysis etc.), biomass pyrolysis and heterogeneous gasification reaction data. Heterogeneous reactions were comparatively investigated in the forms of powder, particles, and a fixed–bed. The powder was investigated in depth with CO₂, O₂, and H₂O (gas fraction 5–20 vol.%; temperature CO₂, O₂ and H₂O, respectively, at 730–790 °C, 360–405 °C, 720–780 °C), while particle reactions and fixed–bed reaction were only studied with CO₂. A model description for a fixed–bed batch reactor was applied, modified, and compared to experimental fixed–bed batch reactor results. This study concludes that determining the appropriate characteristic particle size and parameters for the porous structure of specific biomass char is essential for simulation based on preliminary biomass characterization. Therefore, in future investigations, the description for biomass-specific differences between powder, single particles, and bulk of biomass char may be of greater focus, also taking into consideration O₂ and H₂O.

The Volume 13 published for IJEPR Journal.