Mathematical Modelling and Computational Simulation of Oxy-Combustion Carbon Capture Using Ion-Transport Membranes

Abstract

Global warming is the most challenging environmental problem and is expected to remain so for the next few decades. In June 2025, scientists predicted that it would be extremely difficult to meet the 2030 global temperature reduction milestone. Therefore, it is necessary to double our efforts to reduce global warming through several approaches, including higher renewable energy usage, energy efficiency, and carbon capture. Mathematical modelling and computational simulation are important tools for modelling complex processes that occur in important environmental applications such as carbon capture. In this paper, we present the mathematical modelling of a carbon capture method that allows simultaneous oxygen production and combustion, to allow direct carbon capture after water vapor condensation. The study lays out the development of an oxy-fuel combustion model integrated with an oxygen separation model in two mini-reactors. The model has been validated against recent experimental oxyfuel combustion in a button-cell reactor, and very good agreement has been obtained. The normalized Root Mean Square (RMS) value for the difference between the experimental and predicted results of the permeated oxygen for nonreactive cases was around 4%, and for the reactive cases 6%respectively. The validated model was used to simulate oxygen separation and oxyfuel combustion in annular reactors that can be used for carbon capture in industrial applications as one of the solutions to fight global warming. It was found that it is more efficient to have the air flow in the inner tube for air velocities ranging between 0.05 to 2 m/s. As the sweep velocity increased from 0.05 to 2.5 m/s, the separated oxygen mass flow rate increased by a factor of 5 or higher. For the reacting cases, feeding 2% methane oxy-combustion has increased the oxygen permeation by as much as 17% for annular oxy-combustion cases and by 12% for tubular oxy-combustion cases. The sweeping gas velocity increase seems to be more effective in increasing the oxygen permeation. This effect is still valid under reacting cases.