1. a Department of Chemical Engineering , The University of Trondheim, The Norwegian Institute of Technology , Trondheim, Norway
2. b SINTEF Applied Chemistry , Chemical Engineering Section , Trondheim, Norway
3. c Norsk Hydro Research Centre Porsgrunn , Porsgrunn, Norway
4. d Department of Chemical Engineering , Chemical Reactor Engineering Centre, The University of Western Ontario , London, Ontario, N6A 5B9, Canada