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

Abstract

In 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 (CO 2 ) 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 CO 2 absorption and CO 2 stripping process. The model was then employed to guide the systematic study of the MEA-based CO 2 capture process for the reduction in regeneration energy penalty through parameter optimization and process modification. Important process parameters such as MEA concentration, lean CO 2 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 CO 2 . 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. 24

On the role of solid particles in CO2 bubble nucleation for solvent regeneration of MEA‐based CO2 capture technology

“…It captures CO 2 from major emission sources such as fossil power plant flue gas, and then transfers CO 2 into chemical products or stores it in deep oceans and abandoned mines . Alkanolamine solvents, such as 30% monoethanolamine (MEA) solvent, which possess the characteristic of quick absorption, large absorption capacity, and simple regeneration, have been used widely in postcombustion capture (PCC) . However, this process still raises the question of high energy consumption because of the high heat duty for solvent regeneration, which accounts for nearly 60–80% of the total running cost for a CO 2 capture process …”

“…For instance, Li et al . simulated a MEA regeneration process with improvements to the absorber inter‐cooling process, the rich‐split process, and the stripper inter‐heating process, and the total reboiler duty was reduced from 3.6 MJ/kg CO 2 to 3.1 . Zhao et al .…”

“…1 Carbon capture, utilization, and storage (CCUS) is a promising method for the reduction of postcombustion capture (PCC). 3,4 However, this process still raises the question of high energy consumption because of the high heat duty for solvent regeneration, which accounts for nearly 60-80% of the total running cost for a CO 2 capture process. 5 Many efforts have been made to reduce the energy consumption of the CO 2 capture process by enhancing the stripping process.…”

Exploiting response surface methodology (RSM) as a novel approach for the optimization of carbon dioxide adsorption by dry sodium hydroxide

“…The CO 2 ‐loaded amine solution is drained from the absorber and transported to a stripper upon equilibrium, whereby the CO 2 is released at a higher temperature (>100 °C) . Despite being widely employed at the industrial scale, amine‐consumption‐based solvents such as monoethanolamine have their own limitations, such as the high energy required for sorbent regeneration, the potential of solvent degradation, and equipment corrosion . Furthermore, evaporation and amine loss to the ambient air is a great risk, as the atmospheric degradation of the amine‐based solvents creates an extensive range of byproducts such as aldehydes, amides, nitrosamine, and nitramine, which are harmful to the environment …”

“…Likewise, the separated CO 2 stream from the regeneration column is of high purity. Though the exact percentage is not stated, most adsorption processes deliver a stream with purity higher than 95% . This is pure enough for sequestration.…”