Study of CO2 absorption into monoethanolamine solution in a rotating packed bed

초록

Conventional packed bed (PB) absorbers for post-combustion CO2 capture are hindered by large equipment size and high regeneration energy. Rotating packed bed (RPB) has emerged as a promising alternative by intensifying mass transfer and reducing process footprint. In this study, a lab-scale RPB system employing high-concentration monoethanolamine (MEA) solutions at concentrations of 30-70 wt% was investigated for CO2 absorption. Sensitivity analysis was conducted by varying motor speed (300-800 RPM), liquid flow rate, gas flow rate (3-6 Nm3/h), and reboiler temperature, while maintaining a CO2 capture efficiency of 90 %. The results revealed that higher motor speeds and concentrated MEA solutions enhanced mass transfer and cyclic capacity, while reducing overall power consumption. In addition, an optimal L/G ratio of 6.90 L/m3 minimized the total energy demand, while a regeneration temperature of 102 degrees C was found to be the minimum required. Lastly, the electricity consumption of the RPB was measured and compared with the regeneration energy in the stripper to evaluate the relative magnitude of the RPB power usage. As a result, the electrical energy consumption of the RPB accounted for about 2 % less than the heat duty required by the reboiler. This study demonstrates that an RPB-based CO2 capture system outperforms a PB despite its reduced packing height and reactor volume. The use of highly concentrated MEA solutions further enhances RPB process intensification, offering valuable guidance for industrial-scale CO2 capture system design and optimization.

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