A quest for electrode materials: Heat-stable salts removal from industrial lean amine solution via electro-sorption

The accumulation of heat-stable salts (HSS) deteriorate the performance of gas treatment amine units. In this work, different commercially available electrode materials such as copper, stainless steel, aluminum foil, platinized coated titanium, and nickel foam were tested in a batch mode for the electro-sorption of HSS from industrial lean methyl-diethanolamine (MDEA) solutions. Initially, salt removal was examined by using copper electrodes in two different configurations: inside and outside the designed cell; attributing direct and indirect contact with the lean amine, respectively. The results revealed that indirect electrochemical cell configuration has a zero impact on HSS removal, and hence, all the electrodes were structured inside a cell having direct contact with the MDEA solution. Remarkably, the applied voltage has a significant impact on the removal efficiency of the HSS. Among the tested materials, nickel foam (Ni) and platinized (Pt) coated titanium (Ti) electrodes were the most efficient in the removal of HSS with 6.5% and 9.6% removal at a voltage of 0.8V and 1.2V, respectively. The electrochemical characteristics including areal capacitance and cyclic voltammetry for nickel and Pt coated Ti electrode were also reported. The magnetic forces showed no impact on the removal efficiency of the HSS in the batch mode of operation.