Main content area

Is the biochar produced from sewage sludge a good quality solid fuel?

Pulka, Jakub, Wiśniewski, Dariusz, Gołaszewski, Janusz, Białowiec, Andrzej
Archives of environmental protection 2016 v.42 no.4 pp. 125-134
ash content, biochar, energy, fuel production, fuels, heat, lignocellulose, sawdust, sewage sludge, sulfur, temperature, torrefaction, volatile compounds
The influence of sewage sludge torrefaction temperature on fuel properties was investigated. Non-lignocellulosic waste thermal treatment experiment was conducted within 1 h residence time, under the following temperatures: 200, 220, 240, 260, 280 and 300°C. Sawdust was used as lignocellulosic reference material. The following parameters of biochar have been measured: moisture, higher heating value, ash content, volatile compounds and sulfur content. Sawdust biochar has been confirmed to be a good quality solid fuel. High ash and sulfur content may be an obstacle for biochar energy reuse. The best temperature profile for sawdust torrefaction and fuel production for 1 h residence time was 220°C. At this temperature the product contained 84% of initial energy while decreased the mass by 25%. The best temperature profile for sewage sludge was 240°C. The energy residue was 91% and the mass residue was 85%. Higher temperatures in both cases caused excessive mass and energy losses.