Energy-Efficient and Low-Temperature Gaseous Concentration Swing Adsorption (GCSA)-Based Regeneration Method Utilizing Hydrogen Sweep for Direct Air Capture
- 1Dair Capture, Inc. , 7 Dana Rd , , ,
- 2University of Miami , , , ,
Abstract
Solid sorbent-based direct air capture (DAC) is a promising pathway for durable carbon dioxide removal (CDR), but large-scale deployment remains constrained by sorbent degradation and the high cost and energy associated with temperature-vacuum swing adsorption (TVSA). Here, we introduce a hydrogen (H2)-enabled gaseous concentration swing adsorption (GCSA) process that eliminates vacuum and enables regeneration at 35–70 °C using a closed-loop H2 sweep with a commercial amine sorbent. By lowering the CO2 partial pressure under reducing conditions near ambient pressure, H2-GCSA achieves effective regeneration with reduced thermal severity and suppressed oxidative degradation. Accelerated testing between 65 and 95 °C under oxidative and anaerobic environments demonstrates superior sorbent stability over 100 h under oxygen-free conditions. A process-integrated techno-economic analysis for a 100,000 tCO2/yr modular DAC plant, utilizing a total of less than 8.5 tons of H2 and incorporating downstream H2/CO2 separation via pressure swing adsorption (PSA), projects an energy demand of 2.78 GJ/tCO2 (775 KWh/tCO2) and a capture cost of 81 USD/tCO2, representing a 2–3× lower capital cost and 1.5–4× lower energy demand relative to TVSA. Further process integration using low-grade waste heat and PSA elimination reduces the energy demand to 0.85 GJ/tCO2 (235 KWh/tCO2), with projected costs approaching 31 USD/tCO2. Sensitivity analysis indicates that the sorbent cost below 95 USD/kg enables DAC below 100 USD/tCO2. Collectively, these results demonstrate that H2 sweep-mediated GCSA offers a scalable, lower-energy alternative to vacuum-driven (TVSA) regeneration on a wide range of sorbents, eliminating the sorbent material development risks and addressing a central bottleneck in solid-sorbent DAC.
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BibTeX
@article{thakkar2026energyefficient,
title = {{Energy-Efficient and Low-Temperature Gaseous Concentration Swing Adsorption (GCSA)-Based Regeneration Method Utilizing Hydrogen Sweep for Direct Air Capture}},
author = {Harshul Thakkar and Usman Shareef},
journal = {ACS Omega},
year = {2026},
month = nov,
doi = {10.1021/acsomega.6c05892},
url = {https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c05892/5462435/Energy-Efficient-and-Low-Temperature-Gaseous},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Energy-Efficient and Low-Temperature Gaseous Concentration Swing Adsorption (GCSA)-Based Regeneration Method Utilizing Hydrogen Sweep for Direct Air Capture
AU - Harshul Thakkar
AU - Usman Shareef
PY - 2026
DA - 2026/11/02
JO - ACS Omega
DO - 10.1021/acsomega.6c05892
UR - https://pubs.acs.org/acsodf/article/doi/10.1021/acsomega.6c05892/5462435/Energy-Efficient-and-Low-Temperature-Gaseous
AB - Solid sorbent-based direct air capture (DAC) is a promising pathway for durable carbon dioxide removal (CDR), but large-scale deployment remains constrained by sorbent degradation and the high cost and energy associated with temperature-vacuum swing adsorption (TVSA). Here, we introduce a hydrogen (H2)-enabled gaseous concentration swing adsorption (GCSA) process that eliminates vacuum and enables regeneration at 35–70 °C using a closed-loop H2 sweep with a commercial amine sorbent. By lowering the CO2 partial pressure under reducing conditions near ambient pressure, H2-GCSA achieves effective regeneration with reduced thermal severity and suppressed oxidative degradation. Accelerated testing between 65 and 95 °C under oxidative and anaerobic environments demonstrates superior sorbent stability over 100 h under oxygen-free conditions. A process-integrated techno-economic analysis for a 100,000 tCO2/yr modular DAC plant, utilizing a total of less than 8.5 tons of H2 and incorporating downstream H2/CO2 separation via pressure swing adsorption (PSA), projects an energy demand of 2.78 GJ/tCO2 (775 KWh/tCO2) and a capture cost of 81 USD/tCO2, representing a 2–3× lower capital cost and 1.5–4× lower energy demand relative to TVSA. Further process integration using low-grade waste heat and PSA elimination reduces the energy demand to 0.85 GJ/tCO2 (235 KWh/tCO2), with projected costs approaching 31 USD/tCO2. Sensitivity analysis indicates that the sorbent cost below 95 USD/kg enables DAC below 100 USD/tCO2. Collectively, these results demonstrate that H2 sweep-mediated GCSA offers a scalable, lower-energy alternative to vacuum-driven (TVSA) regeneration on a wide range of sorbents, eliminating the sorbent material development risks and addressing a central bottleneck in solid-sorbent DAC.
SN - 2470-1343
ER -