Membrane reactors for methane steam reforming (MSR)

Methane steam reforming is the most common and cost-effective method for hydrogen production and it contributes about 50% of the world's hydrogen production. Although methane steam reforming is a mature technology, it suffers from significant disadvantages such as mass and heat transfer issues and coke deposition during the reaction. Industrially, methane steam reforming reaction is carried out in conventional reactors and, in order to obtain a highly pure hydrogen stream, several steps are necessary such as the reduction of CO content in the reformate stream by water gas shift reactors, Pressure Swing Adsorption and further hydrogen separation/purification devices. Therefore, in order to intensify the whole process a membrane reactor can be used as alternative solution to the conventional systems. In particular, the use of hydrogen perm-selective membrane inside a reactor allows to combine the chemical reaction and hydrogen separation in only one tool. As a result, high purity hydrogen, methane conversion and hydrogen production enhancement are obtained as well as the possibility to perform methane steam reforming reaction at milder operating conditions than conventional reactors. Therefore in this chapter, the relevant progress achieved so far, the most relevant topics of methane steam reforming via membrane reactor technology and the effects of the most important parameters affecting methane steam reforming in membrane reactors are described and critically reviewed. In addition, an overview on the mathematical models used for simulating methane steam reforming reaction in membrane reactor is also presented and discussed.