How much can novel solid sorbents reduce the cost of post-combustion CO₂ capture? A techno-economic investigation on the cost limits of pressure–vacuum swing adsorption

This paper focuses on identifying the cost limits of two single-stage pressure–vacuum swing adsorption (PVSA)
cycles for post-combustion CO₂
capture if the ‘‘ideal’’ zero-cost adsorbent can be discovered. Through an
integrated techno-economic optimisation, we simultaneously optimise the adsorbent properties (adsorption
isotherms and particle morphology) and process design variables to determine the lowest possible cost of
CO₂ avoided (excluding the CO₂
conditioning, transport and storage) for different industrial flue gas CO₂
compositions and flow rates. The CO₂ avoided cost for PVSA ranges from 87.1 to 10.4 e per tonne of CO₂
avoided, corresponding to CO₂
feed compositions of 3.5 mol% to 30 mol %, respectively. The corresponding
costs for a monoethanolamine based absorption process, using heat from a natural gas plant, are 76.8 to
54.8 e per tonne of CO₂ avoided, respectively showing that PVSA can be attractive for flue gas streams with
high CO₂
compositions. The ‘‘ideal’’ adsorbents needed to attain the lowest possible CO₂ avoided costs have a
range of CO₂ affinities with close to zero N2 adsorption, demonstrating promise for adsorbent discovery and
development. The need for simultaneously optimising the particle morphology and the process conditions are
emphasised.