Enhanced catalytic regeneration of amine solutions using novel Cu/HZSM-5/MCM-41 catalysts

This study proposes an advanced method to tackle CO 2 emissions by enhancing solid acid catalysts, aiming to reduce the high energy consumption and low economic efficiency typically associated with chemical absorption processes. The research involves modifying commercial HZSM-5 zeolites through Cu ion exchange, with the optimal performance observed at a Cu ion content of 2.86 % and a Cu salt concentration of 0.2 M. This modification significantly minimizes the loss of copper ions—a common issue in the impregnation method—resulting in a 76.62 % reduction in the loss of active components. To further improve CO 2 gas-liquid mass transfer, mesoporous MCM-41 zeolites were introduced. Experimental results demonstrate that, at a regeneration temperature of 86°C and a mass ratio of 2:1 for HZSM-5 to MCM-41, the combined catalyst achieves a 61.28 % reduction in relative heat duty compared to the blank sample. Moreover, the energy consumption is 12.33 % and 16.45 % lower than that of HZSM-5 and MCM-41 used individually. Characterization analysis reveals that, under comparable acidic active site densities, catalysts with superior physical pore structures exhibit enhanced catalytic performance. The introduction of mesoporous structures notably improves the bidirectional mass transfer efficiency between carbamate macromolecules and CO 2 molecules. This work successfully demonstrates the synergistic effect of combining Cu ion-modified HZSM-5 zeolites with mesoporous MCM-41, leveraging the abundant active sites of HZSM-5 while harnessing the enhanced mass transfer properties of MCM-41.