This document is an expanded abstract.

Summary

In this contribution, a theoretical sound approach was used to predict the viscosity of CO2-loaded aqueous monoethanolamine (MEA) solutions at conditions of relevance for CO2 capture from post-combustion streams. The approach was based on the soft-SAFT equation of state (EoS) coupled with the Free-Volume Theory (FVT) for the integrated modelling of the absorption of CO2 and viscosity. Results showed that the developed model is capable of predicting the impact of CO2 loadings on the viscosity of aqueous MEA solutions with low deviations to experimental data over a broad range of temperatures and amine concentrations.

Introduction

Aqueous amine solutions are considered to be the gold standard solvents for the removal of CO2 from the gas streams of many industrial processes such as natural gas production, gas ammonia synthesis and power generation from fossil fuels. The CO2 capture process using amine-based solvents involves the cyclic chemical absorption of CO2 in an absorber, followed by regeneration of the CO2-rich solvent at high temperatures in a stripper. The absorber and stripping are generally packed columns for an improved surface contact area. CO2 is recovered as the extracted product from the top of the stripper and the solvent is recirculated back to the absorber, in a closed-loop operation.

Among all, monoethanolamine (MEA) is the most extensively studied amine for industrial gas purification processes. MEA has a hydroxyl group which increases the solubility in water and an amino group responsible for providing the alkalinity necessary to capture CO2, as depicted in the figure below.

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