CO2 absorption enhancement in low transition temperature mixtures-based nanofluids: Experiments and modeling

Q Yi and CA Zhao and CB Lv and GH Wan and MM Meng and LY Sun, SEPARATION AND PURIFICATION TECHNOLOGY, 325, 124584 (2023).

DOI: 10.1016/j.seppur.2023.124584

The enhancement of gas-liquid mass transfer in the CO2 absorption process by Low Transition Temperature Mixtures (LTTMs) based nanofluids was investigated. The effects of loading and size of TiO2 nanoparticles on the CO2 absorption rate were studied experimentally. The absorption rate was found to be improved significantly after adding nanoparticles. The maximum enhancement factor of 1.35 was observed when using nanoparticles with a particle size of 10 nm and a concentration of 0.6 kg/m3. The maximum absorption enhancement factor and mass transfer coefficient were observed when the loading of nanoparticles increased, hence there was an optimal concentration of TiO2 nanoparticles in the CO2 absorption process. For the size of nanoparticles, the CO2 absorption rate was higher when the diameter of nanoparticles decreased. Furthermore, a three-dimensional unsteady mathematical model of gas- liquid mass transfer, which was based on the mechanisms of grazing effect and hydrodynamic effect in the gas-liquid boundary layer, was developed to describe the CO2 absorption enhancement. The model predictions were well consistent with the experimental results, with a maximum deviation of less than 5%, which proved the reliability of the model. Finally, Molecular dynamics simulations were conducted on the absorbent-CO2 system. The results showed that the addition of TiO2 nanoparticles led to a reduction in the simulation box size at the same simulation time, but it did not significantly alter the interaction between LTTMs and CO2. Therefore, it can be inferred that TiO2 nanoparticles enhance CO2 absorption capacity by modifying the mass transfer rate. Through the aforementioned study, this paper explores the experimental and mechanistic aspects of nanoparticle-enhanced absorption of CO2 in LTTMs systems. The research demonstrates the feasibility of nanoparticle-enhanced absorption of CO2 in LTTMs solvents, providing insights into studying nanoparticle-enhanced gas-liquid mass transfer and offering a new research approach for CO2 capture.

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