Intrinsic and Extrinsic Factors Associated with CO2 Capture in a Packed Bed Reactor

Thursday, November 11, 2010: 3:15 PM
250 A Room (Salt Palace Convention Center)
W. Richard Alesi, Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA and John R. Kitchin, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA

In CO2 capture on amine-based sorbents in a packed bed reactor configuration there are intrinsic and extrinsic factors that affect the kinetics of sorption and regeneration. For example, the intrinsic interactions between CO2 and the amine affect the capture capacity and regeneration energy costs. All other sorbent properties such as porosity and particle size are considered extrinsic factors, and these affect the rates of adsorption and regeneration. The complexities of a packed bed system must be corrected and well understood in order to obtain the thermodynamic and kinetic properties of the amine based sorbents. In this work, amine functionalized ion exchange resins (IER) were evaluated to assess the capture properties of their interaction with CO2. IER consisting of identical monofunctional primary amine chains on a polystyrene backbone are characterized at three particle sizes to determine the effect that particle size plays on the effective rate of capture. Additionally the role that water plays in the interaction and possible blocking of the active amine sites is evaluated. Thermogravimetric analyses, in addition to packed bed reactor experiments were used to obtain the capture capacity and capture efficiencies of each amine. This technique consists of an adsorption step, usually conducted at low temperature in the presence of CO2 and a subsequent regeneration step at elevated temperatures under an inert feed stream, to induce the desorption of CO2 from the amine. The molar gas compositions were characterized with an inline mass spectrometer under a wide range of operating conditions including simulated flue gas conditions (12% CO2) as well as gas compositions ranging from pure CO2 to inert gas feed streams, and temperature swings between ambient up to 100 C. We interpret these results with a model developed to decouple the intrinsic and extrinsic factors obtained through packed bed adsorption and desorption experiments allowing us to obtain a better understanding of the thermodynamic properties of the amine CO2 complex.

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See more of this Session: CO2 Capture by Adsorption I
See more of this Group/Topical: Separations Division