(289b) Multi-Scale Dynamic Modeling and Techno-Economic Analysis of a Radial Flow Fixed Bed Contactor for Post-Combustion CO2 Capture

Solid sorbent contactors are a commonly used technology for post-combustion CO₂ capture as they can potentially reduce capital and operational costs of the process. While fluidized, rotary, or moving beds may increase mass and heat transfer efficiency, they can be difficult to operate, require an attrition resistant sorbent, and can be difficult to scale-up from experimental data¹. Fixed bed contactors are easy to construct, operate, and run on a lab scale. Common fixed bed contactors have an axial flow configuration. This configuration, however, leads to large bed volumes and high pressure drops, especially when large volume of flue gas with low concentration of CO₂ needs to be treated². Radial flow fixed bed contactors (RFBR) can mitigate some of the problems mentioned above for the other type of contactors. In an RFBR, the gas flows radially in the reactor, which allows for a higher surface area for gas-solid contact, reducing the size of the vessel and the pressure drop, and therefore the cost of the process. RFFB contactors have been investigated for many applications, including direct air capture^{3, 4}, oxygen generation⁵, and various pressure swing adsorption processes⁵, but a detailed evaluation of RFFB contactors for post-combustion CO₂ capture using temperature swing adsorption that can be used for scale-up and optimization of a commercial system is lacking.

In this work, an RFBR model was developed for a functionalized metal organic framework (MOF). The MOF exhibits an unusual step-shaped isotherm that make it challenging to develop an isotherm model. A model of the sorbent isotherm is developed and validated by using the experimental data. The kinetic model is developed based on the thermogravimetric analysis data. In addition, a multi-scale model is developed. A particle level model is developed that incorporates mass and heat transfer resistance. This model is integrated with a bulk scale model. The multi-scale model is validated with the experimental breakthrough data from a lab-scale reactor. The model is then scaled up for a commercial scale simulating temperature swing adsorption cycle. For this MOF, effective thermal management is of high importance for realizing the potential of this MOF. An economic model was developed and techno-economic analysis was carried out by simulating changes in a number of design and operating variables. Results are compared with the axial flow fixed bed contactor showing considerable differences not only in the pressure drop and volume as has been reported in the literature but also the economics. In particular, capital and operating cost differences between these configurations are of utmost importance for commercialization of these technologies.

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References:

[1] Menendez, M., Herguido, J., Berard, A., Patience, G., Experimental Methods in Chemical Engineering: Reactors – Fluidized Beds. The Canadian Journal of Chemical Engineering. 2019; 97, 2383-2394.

[2] Kareeri, A.A., Zughbi, H.D., and Al-Ali, H.H., Simulation of Flow Distribution in Radial Flow Reactors. Ind. Eng. Chem. Res. 2006; 45, 2862-2874

[3] Yu, Q., Brilman, W., A Radial Flow Contactor for Ambient Air CO2 Capture. Appl. Sci. 2020; 10, 1080

[4] Schellevis, M., Jacobs, T., and Brilman, W., CO2 Capture From Air in a Radial Flow Contactor: Batch or Continuous Operation?. Frontiers in Chemical Engineering. 2020; 2.

[5] Wang, H., Yang, X., Li, Z., Liu, Y., Zhang, C., Xiaojun Ma, X., and Chunwang Li, C., 3-D Modeling of Gas–Solid Two-Phase Flow in a π-Shaped Centripetal Radial Flow Adsorber. Appl. Sci. 2020, 10, 614.