Impact of fluctuating temperature and pressure of injected CO <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si145.svg" display="inline" id="d1e1151"> <mml:msub> <mml:mrow/> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> </mm

This study investigates the influence of oscillatory inlet conditions on CO 2 adsorption performance and energy efficiency in a packed-bed reactor using Computational Fluid Dynamics (CFD) modelling. Baseline operating values of 3 bar and 20 °C were selected as representative conditions, and systematic oscillations in pressure ( A P = ± 0 . 2 to 2 bar) and temperature ( A T = ± 2 to 10 °C) were imposed at frequencies of 0.001 to 0.01 Hz. Three forcing patterns – snusoidal, triangular, and step changes – were considered and compared to steady operation. The results show that pressure oscillations dominate the dynamic adsorption response: large amplitudes ( ± 2 bar) reduce average CO 2 uptake by up to 16% and increase specific energy consumption by 18% relative to steady-state. Temperature oscillations alone have negligible impact under the present baseline, as symmetric forcing cancels over each cycle; however, when temperature oscillations are coupled with pressure swings, they significantly affect the cooling energy load. Among waveform types, triangular oscillations achieve the most favourable balance of adsorption performance and energy demand, while step changes lead to the poorest efficiency. Overall, the findings demonstrate that oscillatory injection conditions generally reduce adsorption performance, with pressure fluctuations exerting the strongest influence, underscoring the importance of pressure-stabilizing strategies for efficient CO 2 capture. • CFD model used to study oscillatory pressure and temperature effects on CO 2 adsorption. • Steady operation provides maximum uptake and lowest specific energy consumption. • Large pressure amplitudes (±2 bar) cut uptake by ∼ 16 % and raise energy use by ∼ 18 % . • Triangular oscillations outperform sinusoidal and step forcing in efficiency trade-offs. • Coupled temperature–pressure swings increase cooling load, unlike temperature alone.