Volume 50

Active Temperature Control Strategy in Adsorption-based Carbon Capture Process for Minimum Exergy Losses Zhixin Huang, Kunteng Huang, Jiaqi Zhang, Ruikai Zhao1*, Shuai Deng

Abstract

Adsorption-based carbon capture is a promising carbon reduction technology for combating climate change. However, the desorption of CO2 from the adsorbent demands a high energy input, which limits this technology‘s further development. In the desorption step of a temperature swing adsorption (TSA) cycle, the heat transfer from the heat source to the adsorbent and the mass transfer of CO2 from the adsorption phase to the gas phase inevitably leads to exergy losses. Moreover, both heat and mass transfer are typically initially fast and then slow down, as the imbalance potential differences starting large but decreasing over time. The initial large potential differences accelerate the process but cause significant exergy losses. A more uniform potential difference distribution over the entire time scale is expected to achieve better balance between the exergy losses and desorption time. In this regard, this study proposes an active control strategy, that is, regulating the potential difference by process temperature control to reduce exergy losses. A one-dimensional numerical model for carbon capture was established to validate the proposed strategy. The optimal temperature-time condition was identified for a case study to guide the process design. The exergy demand of desorption step is reduced effectively under the active temperature control strategy. This study aims to minimize the exergy losses thereby contribute to the large-scale deployment of adsorption-based carbon capture.

Keywords adsorption, carbon capture, exergy, energy efficiency