Optimum conditions for the capture of carbon dioxide with a bubble-column scrubber

A continuous bubble-column scrubber, capturing CO2 gas for scrubber design purpose by using a NaOH solution under a pH-stat operation, is used to search for optimum parameters for a scrubber design by means of the Taguchi method. The parameters are the pH of the solution, gas-flow rate, liquid-flow rate and temperature, with four levels for each. A total of 16 runs are carried out by using a Taguchi experimental design. From the measured CO2 concentrations at the outlet, the absorption rate and overall mass-transfer coefficient can be determined with the support of a steady-state material balance, as well as a two-film model. According to an SiN ratio analysis, a significance sequence influencing the parameters and optimum conditions can be determined. The results show that the gas-flow rate and pH value are significant parameters, while the temperature and liquid flow rate are minor. A total of four sets of optimum conditions will be used to make further verification. The data determined here were found to be optimum. According to the analysis presented here, a policy for a scrubber design can be established. The results could be used to obtain an algae growth solution for biological carbon fixation in a pilot-scale study. (C) 2015 Elsevier Ltd. All rights reserved.