Multiobjective optimization of MEA/DEA/MDEA hybrid amine composition in a natural gas sweetening process

Natural gas has impurities and some of these impurities such as carbon dioxide and hydrogen sulfide have corrosive properties. Carbon dioxide and hydrogen sulfide are called acid gases and must be separated from natural gas. Improper removal of acid gases directly affects the quality of natural gas. In power plants, impurities lead to operational problems that include low efficiency of the fuel and plant. In the worst case, it will reduce the production of the factory, which will lead to a loss of income. Therefore, removing acid gases is a primary requirement. To achieve this goal, many technologies are developed which include absorption using physical and chemical solvents, adsorption, and membrane processes, etc. The method we use in this research to remove acidic compounds is absorption using alkanol-based solvents or the chemical absorption method. In this research, the sweetening process of natural gas by the three-component mixture of MEA/DEA/MDEA was simulated using the HYSYS software. The composition of the mixture was changed according to the mixture design of the experiment (DOE). Finally, a multiobjective function was defined considering the mole fraction of CO۲ and H۲S in the output of the sweetening process, the heat load of the condenser and reboiler of the striper tower, amine price, and corrosivity rate. By minimizing this multiobjective function, the optimum composition of the MEA/DEA/MDEA mixture was obtained. It was concluded that a mixture of ۵۸.۸۴ wt% MEA, ۱.۶۱ wt% DEA, and ۳۹.۵۵ wt% MDEA has the best desirability for simultaneously minimizing acidic gases in the sweet gas and achieving to lowest heat loading, price, and corrosion.

کلیدواژه ها:

Mixture design of experiment ، MEA MDEA DEA hybrid amine ، Gas sweetening process ، Multiobjective optimization ، Process simulation.