Modeling and stability analysis of electrified reverse water–gas shift reactors

Loss-of-control and stability analyses of chemical reactors have traditionally focused on exothermic systems, whereas endothermic processes remain far less explored from a formal dynamical-systems perspective. Nevertheless, disturbances in operating conditions or failures in heat-supply units may also induce critical behaviour in endothermic reactors, including cold-spot formation and loss of operability.In this work, the Varma–Morbidelli–Wu theory of parametric sensitivity analysis is adapted and applied to endothermic reactor systems, with specific focus on fixed-bed Joule-heated reactors. The proposed framework enables systematic identification of stability, operability, and performance limits through operability and performance diagrams expressed as two-dimensional parametric maps. These maps provide a priori tools for reactor design, control, and process intensification under electrified operation.The reverse water–gas shift (rWGS) reaction is adopted as a representative case study due to its relevance in carbon capture and utilization. A thermodynamic assessment and comparative evaluation of literature kinetic models support the development of consistent one- and two-dimensional reactor models, which are used to perform parametric and sensitivity analyses with respect to design variables, operating conditions, and electrical heating intensity.The analysis shows that cold-spot regimes emerge as structurally distinct steady-state operating regimes rather than as purely numerical artifacts. Intensified and high-performing operating windows are identified for both short- and long-contact-time configurations, clarifying the interplay between electrical current, reactor design, and operating conditions in defining operability limits. Moreover, the transition between regimes is governed by the competition between distributed Joule heating and cumulative endothermic heat absorption along the reactor length.Overall, the proposed methodology provides an operability-oriented framework for the analysis of electrified endothermic reactors, supporting identification of operating regimes, operability margins, and performance–thermal trade-offs beyond the specific rWGS case study considered.