Biogas reforming using renewable wind energy and induction heating

Research Progress on Magnetic Catalysts and Its Application in Hydrogen Production Area

The noncontact heating technology of IH targets heat directly where it is needed through the electromagnetic energy adsorption and conversion of magnetic materials. Unlike conventional heating methods, the heat generated by electromagnetic induction of magnetic materials can be applied directly into the reactor without heating the entire device; this new heating method is not only more energy efficient but also safer, cleaner and more sustainable if renewable electricity is adopted; moreover, magnetic catalysts can be recovered and reused by separating chemical reactants and products from the catalyst by the application of a magnetic field, and it can provide the required heat source for the reaction without altering its catalytic properties. Magnetic catalysts with an electric field have been applied to some industrial areas, such as the preparation of new materials, catalytic oxidation reactions, and high-temperature heat absorption reactions. It is a trend that is used in the hydrogen production process, especially the endothermic steam reforming process. Therefore, in this paper, the heat release mechanism, properties, preparation methods and the application of magnetic catalysts were presented. Highlights of the application and performance of magnetic catalysts in the hydrogen production area were also discussed.

Recent Advances in the Development of Highly Conductive Structured Supports for the Intensification of Non-adiabatic Gas-Solid Catalytic Processes: The Methane Steam Reforming Case Study

Structured catalysts are strong candidates for the intensification of non-adiabatic gas-solid catalytic processes thanks to their superior heat and mass transfer properties combined with low pressure drops. In the past two decades, different types of substrates have been proposed, including honeycomb monoliths, open-cell foams and, more recently, periodic open cellular structures produced by additive manufacturing methods. Among others, thermally conductive metallic cellular substrates have been extensively tested in heat-transfer limited exo- or endo-thermic processes in tubular reactors, demonstrating significant potential for process intensification. The catalytic activation of these geometries is critical: on one hand, these structures can be washcoated with a thin layer of catalytic active phase, but the resulting catalyst inventory is limited. More recently, an alternative approach has been proposed, which relies on packing the cavities of the metallic matrix with catalyst pellets. In this paper, an up-to-date overview of the aforementioned topics will be provided. After a brief introduction concerning the concept of structured catalysts based on highly conductive supports, specific attention will be devoted to the most recent advances in their manufacturing and in their catalytic activation. Finally, the application to the methane steam reforming process will be presented as a relevant case study of process intensification. The results from a comparison of three different reactor layouts (i.e. conventional packed bed, washcoated copper foams and packed copper foams) will highlight the benefits for the overall reformer performance resulting from the adoption of highly conductive structured internals.

Electrical Reverse Shift: Sustainable CO2 Valorization for Industrial Scale

Utilization of CO 2 is a requirement for a sustainable production of carbon-based chemicals. Reverse water-gas-shift (RWGS) can valorize CO 2 by reaction with hydrogen to produce a synthesis gas compatible with existing industrial infrastructure. Fully electrified reverse water-gas-shift (eRWGS™) was achieved using integrated ohmic heating and a nickel type catalyst at industrially relevant conditions. Using a feed of H 2 :CO 2 in a ratio of 2.25 at 10 barg, utilizing high temperature operation at 1050°C allowed for production of a synthesis gas with a H 2 /CO ratio of 2.0 and no detectable methane, ideal for production of sustainable fuel by e.g. the Fischer-Tropsch synthesis. Facilitating RWGS through CH 4 as intermediate was found superior to the selective RWGS route, due to higher activity and suppression of carbon formation. The eRWGS™ catalyst is found to provide a preferential emissions free route for production of synthesis gas for any relevant H 2 /CO ratio, enabling production of sustainable carbon-based chemicals from CO 2 and renewable electricity with high hydrogen and carbon efficiency.

Catalytic Depolymerization of Waste Polyolefins by Induction Heating: Selective Alkane/Alkene Production

Low- and high-density polyethylene (LDPE/HDPE) have been selectively depolymerized, without added H2, to C2-C20 + alkanes/alkenes via energy-efficient radio frequency induction heating, coupled with dual-functional heterogeneous Fe3O4 and Ni- or Pt-based catalysts. Fe3O4 was used to locally generate heat when exposed to magnetic fields. Initial results indicate that zeolite-based Ni catalysts are more selective to light olefins, while Ni supported on ceria catalysts are more selective to C7-C14 alkanes/alkenes. LDPE conversions up to 94% were obtained with minimal aromatic, coke, or methane formation which are typically observed with thermal heating. Two depolymerization mechanisms, a reverse Cossee-Arlman mechanism or a random cleavage process, were proposed to account for the different selectivities. The depolymerization process was also tested on commercial LDPE (grocery bags), polystyrene, and virgin HDPE using the Ni on Fe3O4 catalyst, with the LDPE resulting in similar product conversion (∼48%) and selectivity as for virgin LDPE.

A Numerical Investigation of Electrically-Heated Methane Steam Reforming Over Structured Catalysts

The use of electric energy as an alternative system to provide heat of reaction enables the cut-off of CO2 emissions of several chemical processes. Among these, electrification of steam methane reforming results in a cleaner production method of hydrogen. In this work, we perform for the first time a numerical investigation of a compact steam reforming unit that exploits the electrical heating of the catalyst support. First, for such unit we consider the optimal thermodynamic conditions to perform the power to hydrogen conversion; the process should be run at atmospheric pressure and in a close temperature range. Then, among possible materials currently used for manufacturing structured supports we identify silicon carbide as the best material to run electrified steam reforming at moderate voltages and currents. The temperature and concentration profiles in idealized units are studied to understand the impact of the catalyst geometry on the process performances and open-cell foams, despite lower surface to volume show the best potential. Finally, the impact of heat losses is analyzed by considering different operative conditions and reactor geometries, showing that it is possible to obtain relatively high thermal efficiencies with the proposed methodology.

Transient Operation: A Catalytic Chemoselective Hydrogenation of 2-Methyl-3-Butyn-2-ol via a Cooperative Pd and Radiofrequency Heating Directed Kinetic Resolution

The effect of periodic temperature oscillations has been studied for the hydrogenation of 2-methyl-3-butyn-2-ol over a Pd-based catalyst in a micro-trickle bed reactor. This hydrogenation was investigated using a radiofrequency heated reactor under transient conditions using temperature cycling. The dynamic operation using this configuration was found to increase both conversion and selectivity towards 2-methyl-3-buten-2-ol compared to the steady-state operation with an improvement of up to 24% for the selectivity being observed. The developments made here also result in a lower activation energy in comparison to previous data, providing a starting point for radiofrequency heating to enhance reaction rate through the exploitation of thermal cycling at production scale.