Membrane reactors in hydrogen production

Today, the use of membrane reactors for hydrogen production is becoming more and more a reality with various pilot installations all over the world and increasing literature studies focused not only to the development of mechanically and chemically stable membranes with high perm-selectivity but also to integrated processes able to maximize the productivity reducing equipment size and energy consumption. The possibility to combine reaction and separation in the same unit, reducing the whole volume of the plant and increasing its efficiency is the main asset promoting the development of this technology. The scope of this chapter is to highlight the main findings about membrane reactors used in hydrogen production from reforming processes. A deep discussion is presented about the main membrane reactors configurations used for the various processes (from packed bed to fluidized bed to micro-reactors) with a short overview on some representative results on the upgrading of syngas via water gas shift reaction. In addition, by considering water gas shift as reference reaction, Process Intensification metrics are detailed. These parameters together with the traditional variables usually used in the evaluation of the process performance supply additional and important information for the selection of the type of technology and the identification of the operating condition windows for making a process more profitable.