Potential of products from high-temperature pyrolysis of biomass and refuse-derived fuel pellets

The management of energy contained in waste is an important research topic. Among many high-energy wastes, pellets are produced from refuse-derived fuels (RDF) and lignocellulosic biomass. This study investigated high-temperature pyrolysis (800 °C) of biomass and RDF pellets. Experiments were conducted in two reactors: i) on a microscale (thermogravimetric analysis) and ii) on a laboratory scale (fixed-bed reactor) to investigate the yields of the products (char, liquid fraction, and gas) and to characterise products toward their further application. The RDF char contained less carbon than the material before pyrolysis. The carbon content of the biomass char was 90%, almost twice that of the raw material. The biomass and RDF chars were chemically and physically activated to increase their specific surface areas. The chemically activated biomass char had a sorption capacity of 156.2 mg/CO₂ at 25 °C and 0.1 MPa. The kinetics of CO₂ sorption were also examined, and the maximum uptake was observed after 2–3 min. The higher heating value of the liquid phase, including the organic condensed phase, was 28.6 and 25.8 MJ/kg for pyrolysis of biomass and RDF pellets, respectively. The pyrolysis gas composition was analysed separately for the heating and isothermal processes. Due to the high CO, CH₄, and H₂ contents, the gas from the heating stage was characterised by a much higher heating value.