Combustion, emission and slagging characteristics for typical agricultural crop straw usage in heating plants

Abstract The combustion and emissions characteristics of wheat, rice, millet, and tobacco straw are thermally evaluated to overcome the challenges related to their usage in heating plants. Wheat straw exhibits the highest volatile matter, fixed carbon content, and heating value (18.0 MJ/kg). The burning processes of biomass are divided into the vaporisation of moisture, devolatilisation, and oxidation, combustion of char and decomposition of inorganic salts. Wheat straw shows the best combustion, ignition, burnout, and flammability indices of the four analysed crops. It also shows less variation in the determination of the apparent activation energy for the oxidation of volatilisation and the combustion of char and has the highest CO2/CO ratio of 1.17 during combustion. The tendency to cause slagging issues is also evaluated and discussed.