Characterization of sulfur and chlorine behavior during pyrolysis of biomass and waste

Abstract

The aim of this study is to characterize the behavior of sulfur and chlorine during the pyrolysis of biomasses (agricultural residues: corn residues and colza straw) and waste components (cardboard, wool, and PVC), selected for their different compositions and ash contents. Pyrolysis experiments were performed between 365 and 850 °C. The major parts of S for wool and cardboard, and Cl for PVC, initially present in organic forms, are easily released into the gas phase, even below 550 °C, with no interaction with ash-forming elements. For the agricultural residues, both the organically and inorganically associated S contribute to its release. Cl, initially mainly present in inorganic chloride salts (KCl, KClO₄…), is only partly released. In the remaining char for colza straw, sulfur is associated with calcium as CaSO₄, reduced to CaS above 800 °C; for corn residues, sulfur and chlorine are found as K₂SO₄, KCl and MgCl₂.