Effects on ash chemistry when co-firing municipal sewage sludge and wheat straw in a fluidised bed: Influence on the ash chemistry by fuel mixing
2012 (English)Conference paper, Presentation (Refereed)
Municipal sewage sludge (MSS) is of interest for co-combustion with problematic fuels, such as agricultural residues, due to its high content of inorganic elements which may improve combustion properties of such problematic fuels. Ash transformation when co-combusting MSS with the agricultural residue wheat straw was examined using a bench-scale bubbling fluidised bed (5 kW). Wheat straw pellets were combusted with MSS both in a co-pelletized form and co-firing of separate fuel particles. This was done to examine whether there is any advantage to either approach of introducing MSS together with a problematic fuel.
Co-combusting wheat straw with MSS changed the bed agglomeration characteristics from being caused by the formation of low-temperature melting potassium silicates in the fuel ash to being caused by a higher-temperature melting bed ash. This shift in ash chemistry had a significant positive effect on the initial defluidisation temperature. The cyclone ash and fine particulate matter changed from being dominated by alkali in general and alkali chlorides in specific to an increased phosphate and sulphate formation which reduces the risk of alkali-related fouling and corrosion. The influence of aluminosilicates may also play a role in the improvement of fuel ash behaviour.
Place, publisher, year, edition, pages
Umeå: Umeå universitet , 2012.
municipal sewage sludge, wheat straw, fluidised bed, bed agglomeration
Natural Sciences Chemical Engineering
IdentifiersURN: urn:nbn:se:umu:diva-61480OAI: oai:DiVA.org:umu-61480DiVA: diva2:568012
Impacts of Fuel Quality on the Power Production and the Environment, Puchberg am Schneeberg, Austria, September 23-27, 2012
Presented by Nils Skoglund at the conference.2012-11-152012-11-152013-06-24Bibliographically approved