Industrial CO2 absorption into methyldiethanolamine/piperazine in place of monoethanolamine in the absorption column

Abstract

The goal of the study is to assess the use of MDEA + PZ in place of MEA solvent in industrial conditions. In the first part of the paper, a concise package of the models and the correlations in the Rate-based model is introduced to simulate the capture processes. For this purpose, Onda, Bravo-Fair, and, Billet-Schultes mass transfer correlations are evaluated to determine the one with a precise prediction of CO2 absorption. The results show that Bravo-Fair mass transfer correlation has a lower average error, 10.24 %, compared to Onda, 16.41 %, and Billet-Schultes, 27.02 %.In the second part of this paper, different operational and process sensitivity analyses have been performed to investigate the capabilities of the MDEA + PZ in place of the prevalent solvents such as MEA in the industrial environment with the use of the data obtained from Kermanshah petrochemical’s Carbon Dioxide Recovery plant (CDR). According to the sensitivity analysis, which determines the influence of design parameters and operational conditions on CO2 absorption percentage, rich solvent temperature, liquid temperature profile, and CO2 mole fraction profile in the gas phase inside the CO2 absorption tower, the total solvent concentration is the most influential one in CO2 absorption (%) and rich solvent temperature (°C). Hence, in optimal conditions, the absorption percentage can be raised from the base case 64.62 % to 87.44 % for MDEA + PZ compared to 82.86 of MEA. In addition, the rich solvent temperature can be lifted to 53.61 °C in comparison with 47.24 °C for MEA.