Absorption Rate of Carbon Dioxide from Gas Mixture

Absorption of CO2 gas from CO2/Air mixture into aqueous sodium hydroxide solution has been achieved using packed column in pilot scale at constant temperature (T) of 25±1℃.The aim of the present work was to improve the Absorption rate of this process, to find the optimal operation conditions, and to contribute to the using of this process in the chemical industry. Absorption rate (RA) was measured by using different operating parameters: gas mixture flow rate (G) of 360-540 m3/h, carbon dioxide inlet concentration (CCO2) of 0.1-0.5 vol. %, NaOH solution concentration (CNaOH) of 1-2 M, and liquid holdup in the column (VL) of 0.022-0.028 m3 according to experimental design. The measured RA was in the range of RA = 3.235 – 22.340 k-mol/h. Computer program (Statgraphics/Experimental Design) was used to estimate the fitted linear model of RA in terms of (G, CCO2, CNaOH, and VL), and the economic aspects of the process. R-squared of RA model was 91.7659 percent, while the standard error of the estimate shows the standard deviation of the residuals to be 1.7619. The linear model of RA was adequate, the operating parameters were significant except the liquid holdup was not significant, and the interactions were negligible.