Formation of dioxins and other semi-volatile organic compounds in biomass combustion H.K. Chagger a , A. Kendall b *, A. McDonald b , M. Pourkashanian a , A. Williams a a Department of Fuel and Energy, University of Leeds, Leeds LS2 9JT, UK b Department of Geography, University of Leeds, Leeds LS2 9JT, UK Abstract This paper identi®es advantages of using biofuels and biomass mixed with coal in combus- tion. The availability of biomass with regard to landuse is reviewed, followed by a brief account of the combustion process and the concomitant formation of semi-volatile organic compounds. Chemical compositions of selected biofuels and coal are presented. Routes of formation for polychlorinated dibenzodioxins/furans (dioxins and furans) are illustrated with subsequent reference to associated emissions. Graphs in the paper show coal and biofuel propensities for forming dioxin and furan isomers followed by methods for predicting emis- sion levels and isomer distributions within combustion systems. The ®nal sections of the paper summarise recent equilibrium concentration studies and discuss the ongoing combustion experiments being conducted in the University of Leeds' Department of Fuel and Energy. Preliminary results are presented and discussed, ®nishing with three main experimentally- drawn conclusions. # 1998 Elsevier Science Ltd. All rights reserved. 1. Introduction The use of solid biofuels alone or the co-combustion of biomass and coal is a technology which has numerous advantages [1]: . It reduces net CO 2 emissions. The carbon dioxide released during combustion of biomass equals that which is taken in during growth. A full or partial replacement of fossil fuels with biomass would therefore reduce net emissions of CO 2 . Applied Energy 60 (1998) 101±114 0306-2619/98/$Ðsee front matter # 1998 Elsevier Science Ltd. All rights reserved. PII: S0306-2619(98)00020-8 * Corresponding author.