A comparison between amino acid based solvent and traditional amine solvent processes for CO2 removal

With the aim of substituting amine solvents, traditionally employed for post-combustion removal of carbon dioxide from power plants in order to reduce the emissions of this acid gas to the atmosphere, new solvents have been studied. Recently, precipitating solvents have started to be considered for chemical absorption because of their advantages, if compared to MEA aqueous solution. This work focuses on the study of a post-combustion CO2 removal section by employing a 4M potassium hydroxide - 4M taurine aqueous solution and the evaluation of its performance in comparison with the process by traditional MEA solvent. Simulations have been carried out in ASPEN Plus (R), customized by the authors in previous work to represent the potassium taurate system, whose ionic species, reactions and properties, as well as the thermodynamic model, are not defined by default in the software database, and a techno-economic assessment has been performed. Results show that the traditional process by MEA solvent is more expensive, both as for the capital costs (for which corrosiveness influences the selection of the material of construction) and as for the operating costs (with cost for steam at the reboiler being much higher than the ones for cooling and electricity). (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.