Adsorption of Naphthalene on Activated Wood Charcoal Derived from Biomass Gasification

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.