Experimental and numerical mass transfer study of carbon dioxide absorption using Al2O3/water nanofluid in wetted wall column

Abstract

In this study, the CO2 absorption by Al2O3/water nanofluid was investigated in laboratory-scale wetted wall column. Effects of important operation parameters such as, nanoparticle volume fraction, fluid flow rate and temperature on the mass transfer coefficient have been studied under laminar conditions and steady state. According to the experimental results, the mass transfer coefficient of nanofluid is higher than base fluid water and the mass transfer coefficient increases with the increase of nanoparticle concentration, temperature, and fluid flow rate. The mass transfer coefficients Al2O3/water nanofluid were increased by 40.3% and 67.16% with addition of 0.0125 and 0.025 %v/v nanoparticle, respectively. Then, the mass transfer behavior of Al2O3/water nanofluid in an axi-symmetric two dimensional domains was simulated by applying computational fluid dynamics considering Brownian motion mass diffusion coefficient in nanofluid. The CFD results have a good agreement with experimental results. Also, results have shown that the dimensionless CO2 concentration in film layer clearly increases with an increase in nanoparticle volume fraction and the temperature; but when the fluid flow rate increases, the CO2 concentration decrease.