Enhancing energy efficiency in CO2-rich amine solution regeneration using a Cu-modified attapulgite catalysts

Abstract

In recent years, significant attention has been drawn to the advancement of high-performance solid acid catalysts, which enhance the CO₂ desorption efficiency and concurrently lower energy requirements. Although solid acid catalysts show promise in reducing regeneration energy for amine-based CO₂ capture, achieving an optimal balance between activity, cost, and stability remains a major challenge. Herein a series of solid acid catalysts were prepared by modifying attapulgite (ATP) with various CuO_x loading, and the effect of Cu modification on CO₂ desorption performance was compared systematically. The results showed that CO₂ desorption performance of the as-prepared catalysts was in an order of 2/1-CuO_x/ATP > 1/1-CuO_x/ATP > 3/1-CuO_x/ATP > CuO > ATP. The CO₂ desorption capacity and rate were increased by 194 % and 205 %, respectively, the relative heat duty could be reduced by about 64.5 % by using 2/1-CuO_x/ATP to regenerate the rich MEA solution. ATR-FTIR technique was employed to confirm the catalytic effect and a possible catalytic CO₂ desorption mechanism was suggested. Additionally, the catalyst maintained 81% of its initial CO₂ desorption capacity after seven consecutive absorption-desorption cycles, demonstrating excellent recoverability. This study provides a practical strategy for utilizing efficient, affordable and environmentally benign solid acid catalysts for CO₂ desorption, thereby advancing energy-efficient CO₂ capture technology.

Keywords: Attapulgite; CO(2) desorption; Reaction mechanism; Relative desorption heat duty; Solid acid catalyst.