Session: 13-02: Carbon Capture & Cleaner Fossil Fuel Technologies

Paper Number: 138482

138482 - Numerical Assessment of Triply Periodic Minimal Surface Packings for Solvent-Based Carbon Capture 

Abstract: 

The intergovernmental panel on climate change (IPCC)’s assessment report states that carbon dioxide removal will be necessary if its level in the atmosphere is to be stabilized by the end of the century. Solvent-based direct air capture (DAC) of CO₂ is one of the technologies being explored to achieve the necessary reductions. However, the technology is still in its infancy and requires significant efficiency improvements before commercial adoption at scale is not cost prohibitive and can compete with other alternatives. Solvent-based DAC systems are usually composed of a packing material that is wetted by a capture fluid that reacts with the CO₂ in the air stream and effectively removes it. The capture efficiency of the contactor is determined by a complex relationship of capture-fluid dynamics, heat and mass transfer, temperatures, gas flow velocities, contactor geometry and solvent chemical properties. The capture efficiency of the contactor must be balanced with other losses, such as the energy required to move the air through the contactor (i.e., pressure drop). Triply periodic minimal surfaces (TPMS) are a class of differential surfaces that have been explored in multiple engineering applications and have been shown to exhibit excellent performance when used for heat exchangers. Their tortuous path provides a high surface-to-volume ratio and the best trade-off between contact area and pressure drop. Advances in additive manufacturing have curbed limitations associated with the fabrication of these complex lattice structures. Therefore, the production of TPMS surfaces such as the Gyroid, Fischer-Koch and Schwarz-P have all become possible at a reasonable cost. The gyroid TPMS is chosen for a geometrical parametric study due to its superior trade-off between pressure drop and surface area. The gyroid TPMS is evaluated using computational fluid dynamics (CFD) for a variety of unit-cell sizes and porosity levels to explore their potential. A thin-film modeling approach for solvent-based contactors developed and validated against falling film reactor data is used to analyze the parametric effects of different gyroid TPMS shapes. The model was developed with the intent of being a computationally efficient method of simulating these complex geometries at scale. The model makes appropriate assumptions about the nature of the falling solvent film to avoid the use of complex volume of fluid (VOF) methods and reduce computational cost. A gas-liquid mass transfer model is implemented in the commercial software STAR-CCM+ and used to predict the CO₂ capture efficiency and study the trade-off between capture performance and pressure drop through analysis of capture rates, film uniformity, and other relevant variables.

Presenting Author: Flavio Dal Forno Chuahy Oak Ridge National Laboratory

Presenting Author Biography: Flavio Dal Forno Chuahy is a research scientist at Oak Ridge National Laboratory. His expertise lies in the application of multi-phase, multi-physics computational models for the analysis of a variety of clean energy systems. Dr. Chuahy completed his PhD at the University of Wisconsin - Madison.

Authors:

Flavio Dal Forno Chuahy Oak Ridge National Laboratory
Filipe Brandao Oak Ridge National Laboratory
Kellis Kincaid Oak Ridge National Laboratory
Kashif Nawaz Oak Ridge National Laboratory