Indirect air CO2 capture and refinement based on OTEC seawater outgassing

Straatman, Paul J.T.; Sark, W.G.J.H.M. van

doi:10.1016/j.isci.2021.102754

Cited by 10 publications

(4 citation statements)

References 13 publications

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“…There is a worldwide effort underway to find methods of recycling CO 2 , and one method is through its hydrogenation, a process that produces a substitute natural gas [ 1 , 2 ] or transportation fuels, either by Fischer–Tropsch synthesis (FTS) [ 3 , 4 ] or by methanol synthesis (used to produce alternative gasoline [ 5 , 6 ]). Sources of CO 2 include power generation plants [ 7 ], quarry activities [ 8 ], biogas [ 9 ], direct air capture systems [ 10 ], and ocean water [ 11 ]. The H 2 required to produce useful fuels from CO 2 can be generated in a renewable manner through the electrolysis of H 2 O using electricity harvested from solar energy [ 12 ], wind power [ 13 ], or nuclear plants [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

CO2 Hydrogenation: Na Doping Promotes CO and Hydrocarbon Formation over Ru/m-ZrO2 at Elevated Pressures in Gas Phase Media

et al. 2023

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Sodium-promoted monoclinic zirconia supported ruthenium catalysts were tested for CO2 hydrogenation at 20 bar and a H2:CO2 ratio of 3:1. Although increasing sodium promotion, from 2.5% to 5% by weight, slightly decreased CO2 conversion (14% to 10%), it doubled the selectivity to both CO (~36% to ~71%) and chain growth products (~4% to ~8%) remarkably and reduced the methane selectivity by two-thirds (~60% to ~21%). For CO2 hydrogenation during in situ DRIFTS under atmospheric pressure, it was revealed that Na increases the catalyst basicity and suppresses the reactivity of Ru sites. Higher basicity facilitates CO2 adsorption, weakens the C–H bond of the formate intermediate promoting CO formation, and inhibits methanation occurring on ruthenium nanoparticle surfaces. The suppression of excessive hydrogenation increases the chain growth probability. Decelerated reduction during H2-TPR/TPR-MS and H2-TPR-EXAFS/XANES at the K-edge of ruthenium indicates that sodium is in contact with ruthenium. A comparison of the XANES spectra of unpromoted and Na-promoted catalysts after H2 reduction showed no evidence of a promoting effect involving electron charge transfer.

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Section: Introductionmentioning

confidence: 99%

CO2 Hydrogenation: Na Doping Promotes CO and Hydrocarbon Formation over Ru/m-ZrO2 at Elevated Pressures in Gas Phase Media

et al. 2023

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“…ECCs based on EMPC, or pH swing, leverage the pH sensitivity of the CO2 equilibrium, whereby CO2 is absorbed as bicarbonate and carbonate species at high pH values and desorbed at lower pH values as gaseous CO2 [44]. Electrochemically-driven pH swing processes establish the necessary pH conditions for absorption (high pH) and desorption (low pH) through a protoncoupled electron transfer (PCET) redox reaction.…”

Section: Introductionmentioning

confidence: 99%

A Vanadium Redox Flow Process for Carbon Capture and Energy Storage

Afshari,

Refaie,

Aleta

et al. 2024

Preprint

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Climate change mitigation by decreasing worldwide CO2 emissions is an urgent and demanding challenge that requires innovative technical solutions. This work, inspired by vanadium redox flow batteries (VRFB), introduces an integrated electrochemical process for carbon capture and energy storage. It utilizes established vanadium and ferricyanide redox couples for pH modulation for CO2 desorption and absorbent regeneration. The developed process consumes electricity during the daytime—when renewable electricity is available—to desorb CO2 and charge the cell, and it can regenerate the absorbent for further CO2 absorption while releasing electricity to the grid during nighttime when solar power is unavailable. This research explores the process fundamentals and scalability potential, through an extensive study of the system's thermodynamics, transport phenomena, kinetics, and bench-scale operations. Cyclic voltammetry (CV) was utilized to study the thermodynamics of the process, mapping the redox profiles to identify ideal potential windows for operation. The CV results pinpointed a 0.3 V Nernstian overpotential as the thermodynamic minimum required for cell operation. Additionally, polarization studies were conducted to select the practical operating potential, identifying 0.5 V as optimal for the CO2 desorption cycle to provide sufficient polarity to overcome activation barriers in addition to the Nernstian potential. Mass transfer analysis balanced conductivity and desorption efficiency, with a 1:1 ratio identified as optimal for redox-active species and background electrolyte concentration. To further enhance the kinetics of the redox reactions, plasma treatment of electrode surfaces was implemented, resulting in a 43% decrease in charge transfer resistance, as measured by electrochemical impedance spectroscopy (EIS) analysis. Finally, a bench-scale operation of the system demonstrated an energy consumption of 54 kJ/mol CO2, which is competitive with other electrochemical carbon capture technologies. Besides its energy competitiveness, the process offers multiple additional advantages, including the elimination of precious metal electrodes, oxygen insensitivity in flue gas, scalability inspired by VRFB technology, and the unique ability to function as a battery during the absorbent regeneration process, enabling efficient day-night operation.

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“…According to Henry's law (eq 1), CO 2 can be naturally dissolved in water, including seawater, due to the gas−water equilibrium. 24 When the CO 2 concentration increases, the solubility of CO 2 in water (i.e., CO 2 capture capacity) increases because of the correlation between the solubility of CO 2 and gas partial pressure. In addition, as the temperature rises, the gas solubility decreases, necessitating additional circulating water for effective CO 2 capture.…”

Section: ■ Introductionmentioning

confidence: 99%

Unraveling the Potential of Electrochemical pH-Swing Processes for Carbon Dioxide Capture and Utilization

Cao,

Snyder,

Lin

et al. 2023

Ind. Eng. Chem. Res.

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Indirect air CO2 capture and refinement based on OTEC seawater outgassing

Abstract: Indirect atmospheric CO 2 capture from main power generation process in OTEC CO 2 from OTEC purified with energy optimized water scrubber OTEC CO 2 -associated production costs in the range of 15-35 euro per ton

Cited by 10 publications

References 13 publications

CO2 Hydrogenation: Na Doping Promotes CO and Hydrocarbon Formation over Ru/m-ZrO2 at Elevated Pressures in Gas Phase Media

CO2 Hydrogenation: Na Doping Promotes CO and Hydrocarbon Formation over Ru/m-ZrO2 at Elevated Pressures in Gas Phase Media

A Vanadium Redox Flow Process for Carbon Capture and Energy Storage

Unraveling the Potential of Electrochemical pH-Swing Processes for Carbon Dioxide Capture and Utilization

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