Research Projects

Most studies on adsorption-based CO2 capture have focused on developing new adsorbents, neglecting the development of optimal reactor design and operating conditions. However, the performance and cost of adsorption technology are not just a function of adsorbent material, but also depend on the reactor configuration. One way to make adsorption-based CO2 capture a viable alternative to absorption technology is to reduce the energy requirement and cycle time during temperature swing adsorption (TSA). A shorter cycle time implies using the adsorption column longer, leading to lower CO2 capture cost. Moreover, traditional TSA involves passing a hot (purge) gas through the adsorption column to heat the bed, such that the adsorption capacity of the sorbent drops, and the adsorbed gas gets released. In the case of CO2, the heating gas should be easily separable from CO2; otherwise, another unit operation would be required to separate CO2 from the heating gas. For this reason, steam or pure CO2 is a viable option. Many of the sorbents for CO2 deteriorate in the presence of moisture, leaving CO2 as a practical way to heat the bed. To remedy this challenge, alternate heating strategies are required. One such strategy is to heat the bed without a physical medium. Microwave and Joule heating are two such options. Microwaves penetrate the medium and generate heat within the medium. On the other hand, resistors carrying electric current can be placed within the bed to generate heat. These two heating sources also enable using electricity as the energy source instead of fossil fuels. In the near future, as the share of renewable electricity increases, microwave and Joule heating would gain more prominence as a cleaner way of providing process heat. Rapid adsorbent regeneration can be achieved using electrical swing adsorption (ESA) and microwave swing adsorption (MSA). Traditional temperature swing adsorption (TSA) is based on heating the adsorbent by passing a hot gas, leading to a longer regeneration step. Compared to TSA, MSA and ESA generate heat in situ using microwaves or electric current, respectively, and could provide a much shorter regeneration step. Moreover, MSA and ESA allow the use of renewable electricity. No thumb rules or correlations exist to optimize and scale up such systems. To this end, this proposed work will develop these tools by experimental investigation and first-principles model development. In this project, we will investigate the Joule and microwave heated CO2 sorbent regeneration in fixed beds. Experiments will be performed at lab scale and complemented with detailed first-principles modeling and techno-economic analysis (TEA) in ASPEN. Such an approach will allow a robust comparison of the electricity-based and conventional strategies to regenerate a saturated sorbent bed.