Impact of partial regeneration method on the reduction of CO2 desorption energy

Amine-functionalized solid materials have shown efficacy for low-concentration CO2 environments; however, their regeneration is often hindered by slow desorption kinetics at low temperatures. To address this, an innovative approach termed The Partial Regeneration Method is introduced as a driving method to enable low-temperature regeneration of CO2 adsorbents at low concentration levels. Analysis of desorption kinetics mechanisms reveal that at low temperatures, CO2 molecules exhibit reduced kinetic energy and intraparticle diffusion coefficients. Furthermore, as it approaches chemical equilibrium temperature, the re-adsorption reaction rate increases. The partial regeneration method which selectively targets CO2 molecules with low re-adsorption rates could be more effective in a such low temperature conditions. This method involves intentionally halting regeneration midway and proceeding to the next adsorption process. Experimental application of specific energy requirements and scenario analysis demonstrated a 50.7% decrease in energy consumption compared to the conventional methods. By optimizing amine loading to reduce excessive re-adsorption, the shortened cycle period compensates for the decreased adsorption per cycle. Increasing the number of cycles led to a 97.5% improvement in CO2 adsorption capacity over a one-month period. Thus, when faced with unavoidable inefficient low-temperature regeneration conditions, the proposed partial regeneration method emerges as a promising solution for minimizing energy consumption. © 2024 Elsevier B.V.