A new process for the capture of CO2 and reduction of water salinity

Abstract

The present work evaluates a new process for the capture of CO2 and the reduction of water salinity. It is based on the Solvay process without the use of ammonia and involves the reaction of CO2 with saline water such as reject brine in the presence of calcium hydroxide. The effects of operating parameters such as reaction temperature, water pH and reaction stoichiometry on CO2 capture efficiency and sodium removal were examined for both traditional and modified Solvay process. The optimum conditions for maximum CO2 capture efficiency and sodium removal were determined using response surface methodology and were found to be at temperature of 20 °C and a pH of greater than 10 for both processes. At the optimum conditions, CO2 capture of 86% and 99% and sodium removal of 29% and 35% were achieved for the traditional Solvay and the Modified process, respectively. The water pH was found to be a key parameter in the effectiveness of the reaction process; higher pH leads to better process performance in both CO2 capture efficiency and sodium removal. The experimental results clearly illustrated that the Modified Solvay process is superior in terms of CO2 capture efficiency, sodium removal and energy consumption.