Electrolyte solution of MDEA–PZ–TMS for CO2 absorption; response surface methodology and equilibrium modeling

Abstract This research aims to study the performance of MDEA–PZ–TMS​ blends solution in CO2 reactive absorption via a stirrer reactor. Two modeling approaches of the response surface methodology (RSM) and equilibrium modeling using the modified Pitzer model were employed to predict process behavior at the equilibrium state. Five independent variables of temperature, pressure, MDEA, PZ, and TMS concentrations were considered in the ranges of 20–75 °C, 2–8 bar, and 1–5wt%, respectively. Based on the RSM modeling, both CO2 loading and absorption percentage were simultaneously maximized with the degree of importance of 1 and 5, respectively, at operating conditions of 3.5 bar, 32.5 °C, 2wt% TMS, 4wt% MDEA, and 4wt% PZ concentrations. In the equilibrium modeling, the equilibrium CO2 loading was predicted with an average relative error of 4.85% for all empirical data. The present modeling can be applied to various CO2 absorption processes using different electrolyte solutions.