Hydrogen Production with Membrane Systems

It is well-known that hydrogen is conventionally produced via reforming of fossil fuels in large-scale plants. Apart from small-scale hydrogen production from renewable energy sources (mostly using electricity from renewable sources), more than 80% of all the hydrogen is nowadays produced by reforming of natural gas or water-gas shift of coal-derived syngas. In natural gas steam reforming, the efficiency of the hydrogen conversion is very high only when very large plants are considered. In fact, hydrogen production by steam reforming requires multi-step processing, starting from natural gas conditioning, high temperature reformer, high and low temperature watergas- shift (WGS) reactors and a final purification step. Over the last years more emphasis has been put on novel technologies for hydrogen production. These include the exploitation of membrane separation either as a final purification step or integrated in the reforming/WGS step as membrane reactor. In this chapter we will describe in detail the latest developments of membrane preparation for hydrogen production, with particular focus on the selection of the metal alloy and membrane support for different applications (including high-temperature applications). Novel reactor systems integrating such membranes will be discussed and results of research projects on membranes and membrane reactor applications will be highlighted.