(365h) Technoeconomic Assessment of Optimized Adsorption Processes for Post-Combustion CO2 Capture in Hydrogen Plants

Hydrogen is a clean fuel and plays a key role towards building a low-carbon sustainable energy society. While there are renewable sources to produce hydrogen, most of the global hydrogen production relies on fossil fuels like natural gas. To enable low-carbon emission hydrogen production, hydrogen production with CO₂ capture and storage remains an interim plausible solution. The most common route for hydrogen production involves steam methane reforming (SMR) technology. In SMR-based hydrogen plants, one of the main CO₂ emission sources continues to be SMR furnace flue gas.

Vacuum swing adsorption (VSA) technology has been widely considered for post-combustion CO₂ capture. Given very few technoeconomic studies exist for adsorptive-based CO₂ capture, detailed process design based on economics remains a key challenge. In order to fully understand the potential of VSA technology to enable low-carbon hydrogen production, this study provides a technoeconomic assessment of VSA for post-combustion CO₂ capture from SMR furnace flue gas. To this end, an integrated technoeconomic optimization methodology which takes into account process models, scale-up design, vacuum pump performance and comprehensive costing model is developed. Several operating conditions are thoroughly optimized for minimum CO₂ capture cost using genetic algorithm-based optimization with requirements of 95% CO₂ purity and 90% CO₂ recovery. Since the choice of adsorbent is critical for process design, commercial zeolite 13X and metal organic frameworks (MOFs) are assessed for their overall technoeconomic performances and compared against a benchmark solvent case. In addition, the impact of several parameters like vacuum pump efficiency, adsorbent cost, adsorption columns, etc. on the capital and operating costs are also considered. Further, many studies use multiobjective optimization of minimization of energy consumption and maximization of productivity to approximate the optimal cost performance. It is shown that the cost performance approximated through energy-productivity optimization may not reflect the true optimal cost performance obtained by considering cost minimization. At the meeting, the effect of choosing appropriate objective functions and the importance of comprehensive costing model to evaluate adsorption-based processes will be discussed.

Keywords: post-combustion CO₂ capture; adsorption; H₂ plant; process optimization; technoeconomic analysis; metal-organic frameworks; zeolite.

Acknowledgements

This publication has been produced with support from the NCCS Centre, performed under the Norwegian research program Centres for Environment-friendly Energy Research (FME). The authors acknowledge the following partners for their funding contributions to the NCCS Centre: Aker Solutions, ANSALDO Energia, CoorsTek Membrane Sciences, Gassco, KROHNE, Larvik Shipping, Norcem, Norwegian Oil and Gas, Quad Geometrics, Statoil, TOTAL, and the Research Council of Norway (257579/E20). Funding from Canada First Research Excellence Fund through University of Alberta Future Energy Systems is acknowledged.