1. Energy Technology Centre, Box 726, SE-941 28 Piteå, Sweden
2. Division of Energy Engineering, Luleå University of Technology, SE-971 87 Luleå, Sweden
3. Energy Technology and Thermal Process Chemistry, Umeå University, SE-901 87 Umeå, Sweden
4. Department of Analytical Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden