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In Situ FTIR and Tubular Reactor Studies for CO2 Capture of Immobilized Amine Sorbents and Liquid Amine Films

Wilfong, Walter Christopher
http://rave.ohiolink.edu/etdc/view?acc_num=akron1403704363

Abstract Details

2014, Doctor of Philosophy, University of Akron, Chemical Engineering.
In situ Fourier transform infrared spectroscopy (FTIR) and tubular reactor studies with mass spectrometry (MS) revealed the mechanisms and kinetics of CO2 diffusion and adsorption/desorption for immobilized amine sorbents and liquid amine films. CO2 mass transfer limitations of immobilized tetraethylenepentamine (TEPA)/silica sorbents were studied by a novel in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) technique using benzene as a surrogate CO2 probe molecule. Results showed that (i) adsorbed CO2 creates an interconnected network of ammonium-carbamate ions and carbamic acid that inhibits CO2 diffusion, and (ii) readsorption of desorbed CO2 along the pore wall and at the external surfaces limits the CO2 removal rate from the sorbent. CO2 diffusion and adsorption/desorption for different thicknesses of TEPA films were investigated by attenuated total reflectance (ATR) and DRIFTS. Results showed that CO2 strongly adsorbed to NH and NH2 at the top surface of thicker films and formed a strongly bound, interconnected network that reduced the access of CO2 to the bulk amines. Adsorption/desorption of CO2 onto/from immobilized amine particle and pelletized sorbents was studied in a tubular reactor set-up to investigate the sorbents’ performance under different operating conditions. Results showed enhanced CO2 capture on the sorbents in the presence of H2O vapor (wet adsorption), likely resulting from liberation of previously inaccessible amine groups of TEPA. Increasing the CO2 partial pressure by pulsing pure CO2 after wet adsorption, and steam regeneration of the adsorbed species in the CO2 gas environment allows the desorbed CO2 concentration to reach 99+%. A novel, cross-linked porous PVA support (PPc) was synthesized and impregnated with TEPA, polyeythylene glycol 200 (PEG), and other additives for testing as a low cost and stable CO2 capture sorbent. Results showed that PPc exhibited high surface area and pore volume similar to those of silica. Increasing the PEG-OH/TEPA-N ratio of the sorbent enhanced its CO2 capture performance due to dispersion of the NH2 and NH groups by PEG. In situ DRIFTS studies showed a weaker binding strength of CO2 to the amines of the PPc-supported than silica-supported sorbent, suggesting that using PPc sorbents could reduce the cost of sorbent regeneration.
Steven Chuang, Dr. (Advisor)
Bi-Min Newby, Dr. (Committee Member)
Gang Cheng, Dr. (Committee Member)
David Perry, Dr. (Committee Member)
Mark Foster, Dr. (Committee Member)
357 p.
Chemical Engineering
carbon dioxide, infrared spectroscopy, CO2 capture, diffusion, in situ, polymer, immobilized amine sorbent

Recommended Citations

Citations

  • Wilfong, W. C. (2014). In Situ FTIR and Tubular Reactor Studies for CO2 Capture of Immobilized Amine Sorbents and Liquid Amine Films [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1403704363

    APA Style (7th edition)

  • Wilfong, Walter. In Situ FTIR and Tubular Reactor Studies for CO2 Capture of Immobilized Amine Sorbents and Liquid Amine Films. 2014. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1403704363.

    MLA Style (8th edition)

  • Wilfong, Walter. "In Situ FTIR and Tubular Reactor Studies for CO2 Capture of Immobilized Amine Sorbents and Liquid Amine Films." Doctoral dissertation, University of Akron, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1403704363

    Chicago Manual of Style (17th edition)

akron1403704363
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This open access ETD is published by University of Akron and OhioLINK.