ARTICLE pubs.acs.org/IECR
Suitability of a Solid Amine Sorbent for CO2 Capture by Pressure Swing Adsorption A. D. Ebner,† M. L. Gray,‡ N. G. Chisholm,† Q. T. Black,† D. D. Mumford,† M. A. Nicholson,† and J. A. Ritter*,† † ‡
Department of Chemical Engineering, University of South Carolina, Columbia, South Carolina 29208, United States National Energy Technology Laboratory, U.S. Department of Energy, P.O. Box 10940, Pittsburgh, Pennsylvania 15236, United States ABSTRACT: This study showed that a solid amine, composed of poly(ethylenimine) immobilized into a CARiACT G10 silica substrate, is a feasible sorbent for applications in a pressure swing adsorption (PSA) process for postcombustion CO2 capture. This deduction materialized from an extensive study of the behavior of this material over a wide range of industrially relevant conditions using thermogravimetric analysis. The temperature ranged from 40 to 100 °C, the CO2 partial pressure ranged from 1.2 to 100 vol % with the total pressure fixed at 1 atm, the relative humidity ranged from dry conditions to 2 vol %, and the number of consecutive adsorption and desorption cycles ranged from 4 to 76. The results revealed that this solid amine sorbent was very stable under the conditions investigated. Water vapor at a low relative humidity exhibited only a minor and reversible effect on both the thermodynamics and kinetics of the CO2 uptake and release. The isothermal CO2 working capacity ranged between 0.25 and 2.8 mol/kg, increased with increasing CO2 concentration, exhibited a maximum with increasing temperature, and produced a heat of adsorption/reaction of around 50.0 kJ/mol. It was also determined that the optimal operating temperature for a PSA process was around 80 °C for CO2 partial pressures >10 kPa and 6070 °C for CO2 partial pressures 10 kPa and between 60 and 70 °C for CO2 partial pressures
