Experimental study and modeling of simultaneous absorption of CO2 / H2S mixture by silica-water nanofluid in a packed bed column

In this research, mathematical modeling for the absorption process of carbon dioxide and hydrogen sulfide gases using silica-water nanofluid has been performed in a packed bed column. A laboratory apparatus consisting of two towers packed with plastic Raschig rings was prepared for the absorption and desorption process. Experimental tests were performed for three flow rates of 3, 7 and 15 LPM for gas and 0.35, 0.50 and 1 LPM for liquid and the molar fraction of CO2 and H2S in two phases of gas and the liquid are measured. The modeling of the process was done using the overall and partial mass balance equations. Comparison of the obtained model results with the experimental results shows a close correlation between the experimental data and the model and the average relative error was about 10%. Using the obtained model, the component concentration, transferred molar flux and mass flux for liquid and gas are plotted along the column. The results show that with increasing the gas flow rate, both the rate of mass transfer and the slope of the molar fraction gas components were increased. On the other hand, the mass transfer flux in higher gas flow rates achieved to more than twofold. Also, the mass transfer of carbon dioxide was higher than that of hydrogen sulfide, which is due to the higher concentration of carbon dioxide in the inlet gas.