Study on CO₂ bubble absorption and visualization in nanofluids

In this study, Al₂O₃ nanoparticles and methanol are combined into Al₂O₃/methanol nanofluid to enhance the CO₂ absorption rate of the base fluid, which is pure methanol. The absorption experiments are performed in a bubble type absorber equipped with mass flow controller and mass flow meter. The parametric analysis on the effect of the particle fraction on CO₂ absorption rate is carried out. The Al₂O₃ nanoparticle concentration is ranges from 0.005-0.1 vol%. The maximum CO₂ absorption enhancement compared to the pure methanol found to be 3.1% at 0.01 vol% of Al₂O₃/methanol nanofluids at 20°C, and 4.5% at 0.01 vol% of Al2O3/methanol nanofluids at -20°C. Furthermore, the CO₂ bubble absorption visualization is performed by a high speed camera to analyse the gas absorption enhancement mechanism in nanofluids. It appears that the hydrodynamic effect is the main reason for the mass transfer enhancement in nanofluids. It is concluded that the methanol nanofluids are expected to be a promising absorbent for removing the CO₂ gas.