Chemisorption of CO₂ in a Liquid-Driven Rotating Packed Bed: A Mass Transfer Study

A rotating packed bed is a typical process intensification device. However, the motor and dynamic seals may lead to power consumption and reactor safety concerns. This work developed a novel liquid-driven rotating packed bed (LD-RPB) composed of liquid-driven and rotor regions. An impeller driven by liquid jets was utilized to provide rotational motion for a porous packing without a motor and dynamic seals, thus improving reactor safety while guaranteeing effective mass transfer. Prior to practical applications, the rotational characteristics were studied. Liquid-side mass transfer performances were then systematically investigated by the chemisorption of CO2–NaOH, especially evaluating the contributions of the two regions. The effective interfacial area (ae) and volumetric liquid-side mass transfer coefficient (kLae) varied between 271.4–1037.6 m2/m3 and 0.50–1.50 1/s in the rotor region. The liquid-driven region provided extra ae and kLae values ranging from 10.7 to 94.7 m2/m3 and 0.02 to 0.13 1/s, respectively. In a lab-scale setup, the LD-RPB demonstrates comparable mass transfer with conventional RPBs. Meanwhile, the rate of kLae per energy dissipation was larger by 1–2 orders of magnitude, indicating its remarkable energetic efficiency to obtain mass transfer. The LD-RPB, with process intensification potential, presents application prospects in multiphase systems, especially for those with a toxic/hazardous medium.