Abstract

The alarming rise in CO₂ emissions contributes significantly to global temperature increases, even
with the global use of sustainable technologies like solar and wind energy. These efforts, while
helpful, are not enough since industrial processes and human activities continue to release a lot of
carbon dioxide. To tackle this issue, carbon capture and storage or utilization (CCUS) technologies
have become important strategies for reducing emissions. Carbon capture and utilization (CCU) is
particularly gaining attention for its environmental and economic benefits, as it allows us to turn
CO₂ into valuable products. One promising option is the transformation of CO₂ into syngas, which
is a mix of hydrogen and carbon monoxide. Syngas can be used to produce methanol,
hydrocarbons, and other industrial chemicals. A key part of this method is the reverse water-gas
shift (RWGS) reaction, which helps convert CO₂ into CO. This reaction plays an essential role in
using CO₂ for sustainable fuel and chemical production. This study focuses on the development
and modeling of an integrated electrified reverse water-gas shift (RWGS) reactor aimed at
enhancing the efficiency and effectiveness of carbon capture and utilization (CCU) processes. In
the first section of this study, a novel membrane-assisted RWGS reactor is developed for efficient
CO₂-to-syngas conversion, with CFD modeling conducted at 250 °C and 5 bar using H₂ sweep
(∼3% error vs. reference). Coupled with RSM (R² ≈ 99%), the model evaluates the effects of
GHSV (1–100), membrane selectivity (S = 2–1000), sweep ratio (Rf = 0.1–10), and feed ratio (Rc
= 1–4) on CO₂ conversion and pressure drop in co- and counter-current flows. Conversion
improves with higher Rc, Rf, and S, but declines with increasing GHSV. Pressure drop rises with
GHSV but drops with Rc, Rf, and S. Optimization yields a syngas SN of 2.2 for methanol synthesis,
with counter-current flow achieving higher conversion (90%) than co-current (78%). In the second
section of the study, we developed an electrified reverse water-gas shift (E-RWGS) reactor to boost
CO₂ conversion efficiency by integrating a heating element into various reactor types: PBR, PBRS, and PBMR. While PBMR offers the highest conversion due to water removal, it suffers from
notable heat loss. Adding a heating rod reduces this loss, improving CO₂ conversion by 5–10%
across all cases. Molar energy intensity (MEI) analysis shows that E-PBMR and PBMR deliver
the highest energy efficiency across temperatures, demonstrating the effectiveness of
electrification in enhancing RWGS-based CO₂ utilization.