Chemical Engineering and Industrial Chemistry

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

Authors

Abstract

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 € 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 EUR 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 optimizing the particle morphology and the process conditions are emphasized.

Version notes

This is an updated version of the paper uploaded on September 9, 2021

Content

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Supplementary material

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Supporting Information for the Paper
Details corresponding to the following aspects are provided: PVSA plant layout; cost performance of MEA-based CO2 capture; techno-economic modelling framework; dual-site Langmuir isotherm parameters for the two adsorbents; two PVSA cycles and their modelling; PVSA simulation parameters; cost model and cycle scheduling; technical modelling of compressors, vacuum pumps and heat exchangers; optimisation decision variable bounds; optimal decision variables along with the breakdown of capital and operating costs for the optimisations considered. Figures related to: optimal adsorbent properties obtained for the six-step DR cycle, optimal cycle scheduling, and the effect of plant size on PVSA costs are also illustrated.