Abstract
Increasing implementation of renewable energy requires an infrastructure compatible with the intermittent production of green electricity. Herein we show the flexibility of electrically heated steam methane reforming with integrated ohmic heating, through a combination of CFD modelling and lab scale reactor tests. It is shown how start-up from an idle state to operation conditions can be achieved with instantaneous application of the full power required for a steady state conversion of 80%, with initial heating rates exceeding 50 °C/min. The initial heating rate is correlated to the thermal mass of the reactor, with the endothermic reaction governing the temperature profile. Cyclical operation displays no apparent delay between the change in temperature and methane conversion. The highest thermal gradient across the washcoat is predicted at steady state, with no increase during start-up despite the higher heating rates. The highest risk of carbon formation is predicted at the inlet at steady state operation. A temporarily peak in the equilibrated carbon potential is predicted near the outlet during start-up and shutdown between 500 and 600 °C, governed by the thermodynamics of the feed composition. Integrated ohmic heating supports steam methane reforming scalable to industrial conditions, operating closer to thermodynamic limits for carbon formation, and potentially based on the access to intermittent excess of renewable energy.
Highlights
Improving efficiency and a quickly growing global capacity for renewable energy has resulted in economically competitive prices for green electricity compared to fossil fuels [1,2,3]
Integrated ohmic heating supports steam methane reforming scalable to industrial conditions, operating closer to thermodynamic limits for carbon formation, and potentially based on the access to inter mittent excess of renewable energy
This enables homogeneous heating along the entire reactor length and alle viates the risk of transient hotspot formation
Summary
Improving efficiency and a quickly growing global capacity for renewable energy has resulted in economically competitive prices for green electricity compared to fossil fuels [1,2,3]. Without efficient solu tions for large-scale energy storage, the intermittent nature of renewable energy creates a demand for technologies compatible with the excess production [4]. Production of synthesis gas (syngas) through the endo thermic steam methane reforming process (SMR) is a relevant approach for utilizing excess renewable electricity in a transition phase. Combustion of fossil fuels provide heat in conventional SMR plants to drive the strongly endothermic reaction, resulting in emissions of large amounts of CO2-containing flue gas. A typical fired SMR process based on natural gas emits 7–11 kg CO2/kg H2, depending on efficiency and fuel [6,7,8]. The global production of syngas accounts for nearly 3% of global CO2 emissions [9,10]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
