1. Chemical Engineering Department - ETSE, University of Santiago de Compostela, P.O. Box 15782, Santiago de Compostela, Spain, School of Chemical Engineering, State University of Campinas, P.O. Box 6066, 13083-970 Campinas-SP, Brazil, Chemical Engineering Department, Polytechnic School, Federal University of Bahia, 40210-630 Salvador-BA, Brazil, and Unidade de Resonancia Magnética, RIAIDT, edif. CACTUS, University of Santiago de Compostela, P.O. Box 15706, Santiago de Compostela, Spain