Simulation of Carbon Dioxide Removal by Three Amine Mixture of Diethanolamine, Methyldiethanolamine, and 2-Amino- 2-Methyl-1-Propanol in a Hollow Fiber Membrane Contactor Using Computational Fluid Dynamics

Abstract

The present paper investigates the simulation of carbon dioxide removal from natural gas stream by a mixture of three amines of diethanolamine (DEA), methyldiethanolamine (MDEA), and 2-amino- 2-methyl-1-propanol (AMP) in a hollow fiber membrane contactor made from polypropylene using finite volume method (FVM). The effect of structural parameters of length and thickness of membrane and diameter of shell on the removal efficiency was studied and the optimized values were calculated. The calculations were made with the assumption of two-dimensional symmetric geometry and compared with those of three-dimensional one. The effect of number and size of the meshes on the simulation results was also studied. The simulation results were validated against the experimental values from the literature. The results imply that the increase in the length and decrease in the thickness of membrane enhances the removal efficiency. As a result, higher quantities of carbon dioxide are transferred from the shell to the membrane and amine solution inside the tube which decreases the effluent CO₂ of shell and increases the average concentration of CO₂ in the membrane and tube sides. The changes in effluent CO₂ of shell with respect to amine solution concentration and influent CO₂ indicate the insignificant influence of influent CO₂ concentration on the removal efficiency.