Development of Moving Bed Temperature Swing Adsorption (MBTSA) Process for Post-combustion CO2 Capture: Initial Benchmarking in a NGCC Context

A moving-bed temperature-swing adsorption (MBTSA) process has been evaluated for post-combustion CO2 capture in a natural-gas combined cycle (NGCC) context using Zeolite 13X as adsorbent. The performance of the different sections of the reactor (adsorption, regeneration and heat exchange) were modelled in gPROMS using real equilibrium and kinetic adsorption data and typical heat transfer parameters. As a consequence of the internal heat transfer between the hot adsorbent powder leaving the regenerator with the cold powder entering the regenerator, a low specific heat requirement for regeneration of 2.3 GJth/ton CO2 captured is estimated. When also including the electrical energy needed (also compression of CO2) a total energy penalty of 6.5%-points is obtained. For regeneration, flue gas at 222 °C was used for heating and it was assumed that the flue gas was heated after the power plant by using saturated steam condensing at 230 °C. A major reduction in the heat requirement for the process can be gained if the heat required for regeneration is provided from more optimal integration with the steam cycle of the power plant.