Steam methane reforming driven by the Joule heating

The main objective of this work is to present a new particle unresolved 3D-1D DEM-CFD-based model enabling predictions of a new steam methane reforming (SMR) driven by the direct electrical current. The main feature of this technology is the use of metal particles heated by the Joule heat resulting from direct electrical current flowing through metal particles in order to heat the gas phase and catalyst particles (Ni/alpha-Al2O) to sustain endothermic chemical reactions. The model uses six gaseous chemical species (CH4, CO2, CO, H2O, H-2, N-2) in the gas phase inside the catalyst. The Langmuir-Hinshelwood-HougenWatson (LHHW) kinetics is used. The distinguishing feature and the novelty of the model presented in this work consist in the calculation of the 3D distribution of the electric field inside non mono disperse fixed beds. The electric field distribution is used to calculate the Joule heating term for each electrically conducting particle participating in the electrical current flow. Additionally, the new model predictions are compared with alternative models based on the chemical equilibrium principles. The models have been numerically solved using MATLAB. To illustrate the performance of the models and to check the feasibility of a new electrical steam methane reforming concept, we consider a cylindrical electrically insulated tube with a diameter of 0.1 m and a height of 0.5 m, which is filled with metal particles and catalyst particles with diameters of 5 mm and 2 mm, respectively. Parametric runs for different flow rates from 0.0025 kg/s to 0.01 kg/s and electrical power from 6.9 kW to 39 kW have been carried out. Results of simulations showed that an increase in the flow rate value (<(m)over dot>) by keeping constant input electrical power leads to a decrease in the conversion of CH4 proportionally to <(m)over dot>(-1/2). A linear increase in the flow rate and input power leads to a decrease in methane conversion. When the input electrical power is increased, the difference between catalyst particle temperature and gas temperature decreases. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This work presents a new model to predict steam methane reforming driven by direct electrical current, using metal particles heated by the current to sustain chemical reactions. The model calculates the 3D distribution of electric field and compares predictions with alternative models based on chemical equilibrium principles. Results show the impact of flow rate and input power on methane conversion.