Effective direct steam regeneration of bis-iminoguanidine solid sorbent used for carbon dioxide capture

Journal Article · Mon Jun 24 00:00:00 EDT 2024 · Chemical Engineering Journal

DOI:https://doi.org/10.1016/j.cej.2024.153469· OSTI ID:2394727

Jang, Gyoung Gug ^[1]; Seob Jung, Gang ^[1]; Aye Meyer, Pimphan ^[1]; Kasturi, Abishek ^[1]; Stamberga, Diana ^[1]; Custelcean, Radu ^[1]; Tsouris, Costas ^[1]

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1. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

A cost-effective, energy-efficient sorbent regeneration process for phase-changing guanidines used for CO₂ capture was developed based on direct-steam stripping. This approach enhances the regeneration rate, simplifies the overall CO₂ capture process, and reduces the energy cost compared to conventional conductive thermal regeneration. A direct-steam sorbent regeneration reactor was developed, demonstrating that aqueous bis(iminoguanidines) (BIG) sorbents, e.g., methylglyoxal-bis(iminoguanidine) (MGBIG) and glyoxal-bis(iminoguanidine) (GBIG), could be efficiently regenerated with up to ~ 99 % CO₂ recovery through direct-steam stripping. Using low-temperature steam at 100 °C, a 4.5 times faster regeneration rate for GBIG carbonate sorbent (e.g., 30 min for 10 g) was demonstrated compared to conductive-heating (e.g., 135 min for 10 g) at 130 °C. Additionally, fully regenerated MGBIG converts into an aqueous MGBIG solution when the steam condenses onto the sorbent surface. Condensed steam with the guanidine can be easily recycled as an aqueous solution into the gas–liquid contactor to achieve a continuous-flow CO₂-capture process. Molecular dynamics simulation was employed to provide a better understanding of the process. Higher heat transfer rates from steam to guanidine carbonate, compared to air heating, were attributed to the vibration resonance of water molecules within MGBIG with that of vapor molecules and the effective transfer of kinetic energy from vapor to solid. Technoeconomic analysis demonstrated that direct-steam stripping significantly decreases the CO₂ capture cost by 50 % compared to traditional conductive heating methods. Further, enhanced mass transfer facilitated by low-temperature steam and subsequent condensation effectively heats up the H₂O-containing BIG-carbonate crystals, facilitating the desorption of CO₂ from the solid crystals, thereby leading to fast, effective, and energy-efficient sorbent regeneration.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE Office of Fossil Energy and Carbon Management (FECM)
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 2394727
• Journal Information: Chemical Engineering Journal, Journal Name: Chemical Engineering Journal Vol. 495; ISSN 1385-8947
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
CO2 capture
phase-changing guanidine
sorbent regeneration
steam stripping