Gasification of wood packaging waste and valorization of char in polymer composites

This study explores the possibility of repurposing wood packaging residues (WPR) through gasification, adopting a polygenerative approach yielding not only gas, but also char to be valorized as a filler/pigment in polymers. A commercial biomass gasifier was used to test standard pellets (PS) and WPR-derived pellets (PW). Pretreatment was needed to limit metal contaminants in PW, which nonetheless showed higher ash (15.7 vs. 11.1 wt%), and metal content (especially Fe, Cu, and Pb) than PS, affecting the resulting char composition. While feedstock variations primarily affected the inorganic composition and the porosity of the char, operating conditions were found to play a dominant role only in influencing char porosity (with the specific surface area reaching the maximum value of 1006 m²/g). Under standard conditions, PW gasification yielded slightly less char (1.1 vs. 1.3 wt%) but achieved higher cold gas efficiency (60.7 % vs. 56.6 %). The resulting char was tested in polymer matrices, performing well as a black pigment with minimal reduction in tensile properties, thus offering a sustainable alternative to carbon black.