Our main objectives, within the research area of inorganic chemistry in thermal fuel conversion systems, are;
- to provide detailed knowledge on aerosol, ash and deposit formation, corrosion related issues, and, solid residue utilization
- to develop better fundamental understanding and mechanistic models for quantification of ash and deposit formation processes in boilers
- and to test issues of practical relevance for the power plant industry in our experimental lab-scale facilities, as well as to perform measurements on power plant boilers.
Inorganic metal species are present as reactants and products in several important industrial high-temperature processes, e.g. thermal fuel conversion for heat and power production, production of cement or manufacturing of mineral wool for thermal insulation. In the case of heat and power production, the formation of troublesome deposits, goes on in a number of consecutive steps:
- Release of ash forming elements (mainly K, Na, Zn, Pb, S, and Cl) during devolatilization, pyrolysis, and subsequent char burnout
- Formation of aerosols from flame-volatilized ash-forming elements, and formation and entrainment of residual ash (i.e. bottom and fly ash) during char burnout
- Transport of the different ash forming species gases, droplets and particles from the bulk gas to the heat transfer surfaces, and adhesion of these to the heat transfer surfaces
- Build-up, sintering (consolidation), shedding, and heat transfer in deposits.
Our philosophy is to understand the entire process, and we have carried out fundamental and applied research on all the above sub processes.
We are active within a wide range of ash-related issues:
- Ash and deposit formation in biomass suspension-fired boilers
- Formation of aerosols during fixed-bed thermal conversion of biomass and waste
- Lab-scale investigation of high-temperature corrosion
- Thermodynamic modeling of ash and trace element chemistry in gasiification processes
- Release and transformation of alkali, sulfur, chlorine and trace elements in boilers fired with biomass or waste
- Application of additives to minimize deposition and corrosion
- Quantification of deposit shedding
- Fixation of volatile metals as non-volatile, non-leachable solid products in rotary kilns
- Improvement of clinker quality in cement burning processes
- Recycling of nutrients from ashes as fertilizers