A detailed screening on the mass transfer modeling of the CO2 absorption utilizing silica nanofluid in a wetted wall column

Abstract

The low CO2 absorption in water is a major issue for the water-based CO2 capture technology. The current study focuses on augmentation effect of silica nanoparticles in a water-based nanofluid system on CO2 absorption experiments, carried out in a wetted wall column (WWC). Central composite design (CCD) and response surface methodology (RSM) have been applied to predict the individual and possible interaction influences of the most important operating variables, including absorption temperature, (25–45 °C), nanofluid flow rate, (100–300 mL/min), and concentration (0–1 %w) under atmospheric pressure. The propriety of the RSM model has been confirmed through R-squared and adjusted determination coefficients (R2 = 0.9757, and Adj-R2 = 0.9605).The combination of temperature and liquid flow rate, as well as liquid flow rate and concentration, has been proved to be highly effective for CO2 absorption in gas-liquid mass transfer experiments. The findings further have revealed that the impact of temperature at low flow rates is sensible on the gas-liquid mass transfer. Moreover, low absorption temperatures and high flow rates of silica nanofluid can dramatically enhance the liquid-side mass transfer coefficient. It was found that under the optimal operation condition, the enhancement ratio of the predicted kl in the presence of silica nanoparticles can be over 1.37.