Comparisons of amine solvents for post-combustion CO2 capture: A multi-objective analysis approach

• The post-combustion CO2 capture performances of three amine solvents were compared.
• DEA has potential for lower energy penalty and capital cost than 11 mol% MEA and AMP.
• There are tradeoffs in capital cost and energy penalty in CO2 capture processes.

Amine solvents are of great interest for post-combustion CO2 capture applications. Although the development of new solvents is predominantly conducted at the laboratory scale, the ability to assess the performance of newly developed solvents at the process scale is crucial to identifying the best solvents for CO2 capture. In this work we present a methodology to evaluate and objectively compare the process performance of different solvents. We use Aspen Plus, with the electrolyte-NRTL thermodynamic model for the solvent CO2 interactions, coupled with a multi-objective genetic algorithm optimization to determine the best process design and operating conditions for each solvent. This ensures that the processes utilized for the comparison are those which are best suited for the specific solvent. We evaluate and compare the process performance of monoethanolamine (MEA), diethanolamine (DEA), and 2-amino-2-methyl-1-propanol (AMP) in a 90% CO2 capture process from a 550 MW coal fired power plant. From our analysis the best process specifications are amine specific and with those specific, optimized specifications DEA has the potential to be a better performing solvent than MEA, with a lower energy penalty and lower capital cost investment.

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