Removal of heat stable salts from aqueous solutions of N-methyldiethanolamine using a specially designed three-compartment configuration electrodialyzer

The heat stable salts (HSS) generated from the gas desulfurization using N-methyldiethanolamine (MDEA) solvents caused many problems such as solution froth, corrosion and fouling of the equipment. In this paper, a specially designed electrodialysis (ED) was employed to remove the heat stable salts from industrial aqueous MDEA solutions. The heat stable salts were successfully removed by adjusting the arrangement of cation- and anion-exchange membranes. To ensure a stable and durative desalination process, appropriate operation parameters such as applied potential and the flow rate were selected as voltage; 9 V and flow rate; 40 L/h. The experimental results show that about 90% of HSS were removed from aqueous solutions of MDEA solvents while the loss ratio is less than 9% under the appropriate conditions.