Structured Catalysts and Non-conventional Reactor Designs for Energy Applications

Abstract

Process intensification is now considered to be the solution for the efficient scaling down of energy-intensive chemical processes to enable the exploitation of small, remote and associated natural gas reservoirs. However, the approach is not trivial and requires the design of innovative catalytic reactor concepts. Structured catalysts are strong candidates for promoting the development of such processes thanks to their superior heat and mass transfer properties. Different types of substrates have been proposed, including honeycomb monoliths, open-cell foams and periodic open cellular structures. Among these, thermally conductive metallic cellular substrates have attracted attention in view of de-bottlenecking heat transfer-limited exo- or endo-thermic processes in tubular reactors. The catalytic activation of these geometries is critical. These structures can be washcoated with a thin layer of catalytic active phase, but the resulting catalyst inventory is limited. A possible way to exploit the advantage provided by conductive structures while increasing catalyst load relies on packing the cavities of the metallic matrix with catalyst pellets. Recently, this new reactor concept has been successfully demonstrated at the lab scale. As an example, we will review herein its application to the intensification of two key processes for the energy scenario: (1) endothermic small-scale methane steam reforming for distributed hydrogen generation; and (2) the production of clean liquid fuels from synthesis gas via exothermic Fischer–Tropsch synthesis.