Systematic study of aqueous monoethanolamine‐based CO2 capture process: model development and process improvement

Kangkang Li,Moses Tade,Weiliang Luo,Hai Yu,Paul Feron,Ashleigh Cousins,Jian Chen

doi:10.1002/ese3.101

Abstract

AbstractIn this paper, we present improvements to postcombustion capture (PCC) processes based on aqueous monoethanolamine (MEA). First, a rigorous, rate‐based model of the carbon dioxide (CO2) capture process from flue gas by aqueous MEA was developed using Aspen Plus, and validated against results from the PCC pilot plant trials located at the coal‐fired Tarong power station in Queensland, Australia. The model satisfactorily predicted the comprehensive experimental results from CO2 absorption and CO2 stripping process. The model was then employed to guide the systematic study of the MEA‐based CO2 capture process for the reduction in regeneration energy penalty through parameter optimization and process modification. Important process parameters such as MEA concentration, lean CO2 loading, lean temperature, and stripper pressure were optimized. The process modifications were investigated, which included the absorber intercooling, rich‐split, and stripper interheating processes. The minimum regeneration energy obtained from the combined parameter optimization and process modification was 3.1 MJ/kg CO2. This study suggests that the combination of a validated rate‐based model and process simulation can be used as an effective tool to guide sophisticated process plant, equipment design and process improvement.

Highlights

Global climate change caused by the increasing atmospheric concentration of greenhouse gases such as carbon dioxide (CO2), has led to great interest in the development of CO2 capture and storage (CCS) technologies [1,2,3,4,5]
Upon combining the benefits of the three process modifications, the regeneration duty was reduced to 3.11 MJ/kg CO2, which is a 13.6% reduction in reboiler duty compared to the reference case
The combination of pilot-plant trials and process modeling has demonstrated that a validated rate-based model was an effective and reliable tool to evaluate and improve the MEA-b ased CO2 capture process

Summary

Introduction

Global climate change caused by the increasing atmospheric concentration of greenhouse gases such as carbon dioxide (CO2), has led to great interest in the development of CO2 capture and storage (CCS) technologies [1,2,3,4,5]. Using the pilot plant results, a rigorous, rate- based model was developed in Aspen Plus® V7.3 and used to evaluate the MEA-based CO2 capture process. This electrolyte NRTL model has been validated to accurately predict the vapor–liquid equilibrium, aqueous speciation, heat capacity, and CO2 absorption enthalpy of the MEA–H2O–CO2 system with a wide application range: MEA concentration up to 40wt.%, CO2 loading up to 1.33, temperature up to 443 K and pressure up to 20 MPa [35] These conditions cover all the conditions used in the pilot plant and simulations studied. The RateSep simulator embedded in Aspen Plus was used to simulate the aqueous MEA-based CO2 capture process This simulator allows the user to divide the tray column or packed column into different stages and provides more accurate and detailed description of CO2 absorption behavior at each stage based on the material and energy balance.

G Gas sample point

Conclusion

Findings

Conflict of Interest