This review covers the current state, challenges, and future directions of catalytic combustion technologies for mitigating fugitive methane emissions from the fossil fuel industry. Methane, a potent greenhouse gas, is released from diverse sources, including natural gas production, oil operations, coal mining, and natural gas engines. The paper details the primary emission sources, and addresses the technical difficulties associated with dilute and variable methane streams such as ventilation air methane (VAM) from underground coal mines and low-concentration leaks from oil and gas infrastructure. Catalytic combustion is a useful abatement solution due to its ability to destruct methane in lean and challenging conditions at lower temperatures than conventional combustion, thereby minimizing secondary pollutant formation such as NO_X. The review surveys the key catalyst classes, including precious metals, transition metal oxides, hexa-aluminates, and perovskites, and underscores the crucial role of reactor internals, comparing packed beds, monoliths, and open-cell foams in terms of activity, mass transfer, and pressure drop. The paper discusses advanced reactor designs, including flow-reversal and other recuperative systems, modelling approaches, and the promise of advanced manufacturing for next-generation catalytic devices. The review highlights the research needs for catalyst durability, reactor integration, and real-world deployment to enable reliable methane abatement.

Fugitive methane emissions account for a significant proportion of greenhouse gas emissions, and their elimination by catalytic combustion is a relatively easy way to reduce global warming. New and novel reactor designs are being considered for this purpose, but their correct and efficient design requires kinetic rate expressions. This paper provides a comprehensive review of the current state of the art regarding kinetic models for precious metal catalysts used for the catalytic combustion of lean methane mixtures. The primary emphasis is on relatively low-temperature operation at atmospheric pressure, conditions that are prevalent in the catalytic destruction of low concentrations of methane in emission streams. In addition to a comprehensive literature search, we illustrate a detailed example of the methodology required to determine an appropriate kinetic model and the constants therein. From the wide body of literature, it is seen that the development of a kinetic model is not necessarily a trivial matter, and it is difficult to generalize. The model, especially the dependence on the water concentration, is a function of not only the active ingredients but also the nature of the support. Kinetic modelling is performed for six catalysts, one commercial and five that were manufactured in our laboratory, for illustration purposes.

Fugitive methane emissions contained in the ventilation air (VAM) from underground coal mines make a significant contribution to the global methane emissions. These methane emissions have a high global warming potential (GWP) and should be mitigated to combat climate change. This study reports on a novel integrated recuperator reactor concept designed to mitigate these low-concentration methane streams using catalytic combustion. The paper analyzes the heat recovery aspects of the novel design and illustrates a computer-aided design approach to system development. Both computational and experimental methods were used in the investigation. The double-spiral counterflow design is shown to be able to eliminate methane from the flow stream with the feed at room temperature. A methodology is illustrated that can be used to determine the operating limits of the proposed recuperative reactor system. This system is suitable for use inside a mine.

Reverse electrodialysis (RED) is an emerging process intensification technology for sustainable energy generation from the salinity gradient between concentrated brines and dilute streams. Concentrated brines, generated in large volumes by seawater reverse osmosis (SWRO) desalination, mining operations, and saltworks, represent an abundant and underutilised resource whose energetic valorisation via RED can simultaneously reduce brine disposal impacts and contribute to decarbonising the water-energy nexus. This review critically examines existing simulation and modelling approaches for RED systems applied to concentrated brines, covering ion transport models, thermodynamic and exergy frameworks, semi-empirical stack models, multi-physics computational fluid dynamics (CFD), and data-driven machine learning (ML) methods. The review identifies the principal knowledge gaps limiting large-scale deployment: the incomplete description of multicomponent, multivalent ion transport in real brines; the translation of validated laboratory models to pilot and industrial stacks; and the absence of techno-economic and life-cycle analysis integrated with process models. Future research should focus on hybrid models that couple high-fidelity electrochemical simulation with experimental calibration, ML-accelerated parametric studies, and system-level integration of RED with reverse osmosis and membrane distillation. This work provides a structured assessment of current modelling capabilities and a roadmap for simulation-driven optimisation of RED technology.

Reverse electrodialysis (RED) is an emerging process intensification technology for sustainable energy generation from the salinity gradient between concentrated brines and dilute streams. Concentrated brines, generated in large volumes by seawater reverse osmosis (SWRO) desalination, mining operations, and saltworks, represent an abundant and underutilised resource whose energetic valorisation via RED can simultaneously reduce brine disposal impacts and contribute to decarbonising the water-energy nexus. This review critically examines existing simulation and modelling approaches for RED systems applied to concentrated brines, covering ion transport models, thermodynamic and exergy frameworks, semi-empirical stack models, multi-physics computational fluid dynamics (CFD), and data-driven machine learning (ML) methods. The review identifies the principal knowledge gaps limiting large-scale deployment: the incomplete description of multicomponent, multivalent ion transport in real brines; the translation of validated laboratory models to pilot and industrial stacks; and the absence of techno-economic and life-cycle analysis integrated with process models. Future research should focus on hybrid models that couple high-fidelity electrochemical simulation with experimental calibration, ML-accelerated parametric studies, and system-level integration of RED with reverse osmosis and membrane distillation. This work provides a structured assessment of current modelling capabilities and a roadmap for simulation-driven optimisation of RED technology.

Palladium supported on oxide carriers is among the most active catalyst systems for methane combustion, yet the role of the support in governing Pd speciation and reaction pathways remains incompletely resolved. Here, ultra-low-loading Pd/Al₂O₃, Pd/SiO₂, Pd/TiO₂, Pd/ZrO₂ and Pd/CeO₂ catalysts were investigated by quantitative CO-FTIR site counting, in situ DRIFTS using CH₄, CO and HCOOH probe molecules, and fixed-bed kinetic testing. CO-FTIR revealed support-dependent populations of CO-accessible Pd centres, with experimentally determined CO absorption coefficients providing the basis for their quantification. The low apparent activation energies and convergence of the high-temperature rates indicate a substantial contribution from mass transport, limiting the kinetic comparison to apparent catalytic performance. Across CH₄, HCOOH and CO sorption experiments, methane oxidation is consistent with a proposed methoxy → formate → carbonate sequence whose extent and thermal stability are support-dependent. CeO₂ and ZrO₂ enable carbonate formation and removal, Al₂O₃ favours carbonate retention, and SiO₂ shows no reliably detectable chemisorbed intermediates. These findings link quantitative Pd site counting with a support-resolved mechanistic hierarchy, suggesting that efficient methane combustion benefits from both dispersed PdO/Pd⁺ centres and a redox-active support that promotes oxygenate turnover rather than surface trapping.