Membrane reactors for sustainable hydrogen production through steam reforming of hydrocarbons: A review

Membrane reactors - as promising technology for pursuing the Process Intensification Strategy in various chemical processes - were reviewed in the field of steam reforming of methane and liquid hydrocarbons for sustainable hydrogen production. A summary of the advantages and disadvantages of each considered process was presented. Drawbacks and current issues of the traditional reactors in fuel processing processes, which can be overcome using membrane reactors, were also described. In particular, steam reforming processes are the major hydrogen production methods; therefore, in this review the effects of different operating parameters, such as reaction temperature, pressure, feed composition, reactor configuration, feed and sweep gas flow rates were analyzed and discussed in terms of methane conversion, hydrogen recovery, hydrogen yield and CO selectivity. A deep discussion was proposed about the effects of the hydrogen removal from reaction zone (the so called "shift effect") toward the permeation zone in the membrane reactors, highlighting the benefits of their adoption over the traditional reactors.