Since 1994 Prof. Hans-Jörg Bart has been the Chair of Separation Science and Technology at the Technische Universität Kaiserslautern, Germany. Prior to this he was head of the Christian Doppler Laboratory of Modelling Reactive Systems in Process Engineering at the University of Technology, Graz, Austria. He has over 30 years of experience in heat and mass transfer in basic unit operations and two-phase flow simulations. His special research interest is the design and operation of polymeric heat exchangers as an interesting niche technology. He has published more than 300 scientific papers in peer-reviewed international journals and has edited and contributed to several books and book chapters. Dr. Stephan Scholl has been a professor of chemical and thermal process engineering and director of the relevant institute at the Technische Universität Braunschweig, Germany. From 1991 to 2002 he worked as an R&D engineer, logistics consultant and senior research manager at BASF AG, Ludwigshafen, Germany. He has over 23 years of industrial as well as academic experience in heat transfer with an emphasis on evaporation, distillation, equipment design as well as fouling and cleaning. His research interests include the design of sustainable processes with a focus on recycling strategies as well as ecological assessment of the related processes. He has contributed to several monographs on these topics and has published more than 120 scientific papers in peer-reviewed international journals.