Modelling of CO ₂ and H ₂O Interaction During Adsorption Cycles on Hydrotalcite for SEWGS Applications

Abstract

Sorption Enhanced Water Gas Shift (SEWGS) is an intensified pre-combustion capture process, based on a potassium promoted Mg/Al-hydrotalcite sorbent. The technology has demonstrated low energy requirements and high capture performances in real industrial settings within the Iron and Steel sector. Reactor modelling is an essential tool to develop energy and cost-efficient SEWGS units. The TNO developed model captures the fundamentals of the gas-solid thermodynamic and kinetic interactions, to accurately predict the multi-column behaviour, allowing for unit sizing and quantification of the energy requirements. The updated interaction model consists of Langmuir interaction for CO₂, a competitive interaction site for CO₂ and H₂O, an exchange site where either CO₂ or H₂O is adsorbed and a pore condensation for high-pressure H₂O. The updated model is validated against single column and multi-column operation with simulated blast furnace gas.

Keywords: Hydrotalcite, Adsorption, CO2 capture, Sorption equilibrium.