Gas-liquid mass-transfer behavior of packed-bed scrubbers for floating/offshore CO2 capture

Abstract

The amine-based CO2 capture performance of packed bed scrubbers onboard offshore floating vessels was assessed in a systematic study using a hexapod robot with six-degree-of-freedom motions and an embarked column packed with structured elements (M500X) and Raschig rings. The potential bottlenecks stemming from ship tilts and oscillations on the mass transfer performance of the packed-bed scrubber were addressed in terms of effective gas-liquid interfacial area, CO2 removal efficiency, and overall volumetric mass-transfer coefficient. The results revealed that the CO2 absorption performance under offshore conditions would deviate from those measured with conventional vertical/stationary packed bed scrubbers. The effective gas-liquid interfacial area was found to decrease with incrementing tilt angle between 0° and 15° both for structured and random packings. Under column roll and roll + pitch oscillations, the interfacial area was also found to diminish monotonically with the oscillation period. Findings from this work indicate that the effect of offshore conditions and their influences on the packed-bed performance should be carefully considered in the design and scale-up of scrubber units subject to offshore floating perturbations since the mass transfer characteristics of packed beds onboard floating vessels are found to degrade with scrubber inclinations and oscillations.