Abstract
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.
Highlights
CO2 is a well-known greenhouse gas and its concentration raised significantly in the last decades of the century due to human activities
The pressure of the reformer is typically dictated by the subsequent use of the syngas at industrial level, if the aim is hydrogen generation at the small scale, a significant advantage is achieved by operating the reactor at low pressure
By further increasing the temperature the R-water gas shift reactions (WGS) reaction is favored, inducing higher heat demand and at the same time decreasing of the H2 fraction in the feed
Summary
CO2 is a well-known greenhouse gas and its concentration raised significantly in the last decades of the century due to human activities. To mitigate the increasing worldwide CO2 emissions, drastic changes in energy generation technology and energy utilization in key sectors of the industry are required. The Sustainable Development Scenario, issued by International Energy Agency (IEA), states that, to reduce the global temperature increase by 1.5°C, the energy and industrial sectors should reduce their CO2 emissions by 50% by 2050. This calls for a drastic change in the utilization of feedstocks, an increase of the efficiency of industrial processes of the chemical industry, and in the energy generation (International Energy Agency, 2021). Hydrogen is a carbon neutral fuel that can be used in substitution to conventional ones with reduced environmental impact (Bakhtyari et al, 2019)
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