Optimization of a Solvay-Based Approach for CO2 Capture

Abstract

The present work optimizes the CO 2 capture based on the Solvay process, where carbon dioxide is passed into ammoniated brine and reacts with sodium chloride to form a precipitate of sodium bicarbonate and a soluble ammonium chloride. The process has the dual benefit of decreasing sodium concentration in the reject brine and reducing carbon dioxide emissions to the atmosphere. Process parameters were studied in a semi-batch reactor to determine their effect on CO 2 capture efficiency and ions removal. The optimum conditions for maximum CO 2 capture efficiency and ions removal have been determined using response surface methodology. The optimum CO 2 capture efficiency and ions removal was found to be at temperature of about 19 o C, a gas flow rate of 1.54 L/min, and a molar ratio of 3.3NH 3 :1NaCl. The CO 2 capture efficiency in 180 min was equal to 86% and the maximum sodium removal was 33%. These results indicated the technical feasibility of the Solvay approach for the capture of CO 2 through reactions with desalination reject brine. Index Terms-Desalination reject brine, CO 2 capture, sodium bicarbonate, sodium removal, Solvay process.