An efficient approach to separate CO2 using supersonic flows for carbon capture and storage. (15th March 2019)

• Record Type: Journal Article
• Authors: Wen, Chuang; Karvounis, Nikolas; Walther, Jens Honore; Yan, Yuying; Feng, Yuqing; Yang, Yan
• Is Part Of: Applied energy. Volume 238(2019)
• Page Start: 311
• Page End: 319
• Publication Date: 2019-03-15
• Subjects: CO2 separation -- Carbon capture and storage -- Supersonic flow -- CO2 emission; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2019.01.062
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: Propose an alternative approach to efficiently separate CO2 using supersonic flows. Develop an accurate CFD model to predict the CO2 condensation in supersonic flows. Compare the condensation flow and conventional dry gas models for CO2 fluid flows. Dry gas approach calculates wrong static temperature much lower than triple point. Condensation flow model predicts 18.6% condensed liquid fraction of the total mass. Abstract: The mitigation of CO2 emissions is an effective measure to solve the climate change issue. In the present study, we propose an alternative approach for CO2 capture by employing supersonic flows. For this purpose, we first develop a computational fluid dynamics (CFD) model to predict the CO2 condensing flow in a supersonic nozzle. Adding two transport equations to describe the liquid fraction and droplet number, the detailed numerical model can describe the heat and mass transfer characteristics during the CO2 phase change process under the supersonic expansion conditions. A comparative study is performed to evaluate the effect of CO2 condensation using the condensation model and dry gas assumption. The results show that the developed CFD model predicts accurately the distribution of the static temperature contrary to the dry gas assumption. Furthermore, the condensing flow model predicts a CO2 liquid fraction up to 18.6% of the total mass, which leads to the release of the latent heat to the vapour phase. The investigation performed in this study suggests that the CO2 condensation in supersonic flows provides an efficient and eco-friendly way to mitigate the CO2 emissions to the environment.