Parameters influencing the rate-based simulation of CO2 removal units by potassium taurate solvent

CCS (Carbon Capture & Storage) is being widely considered for reducing the emissions of greenhouse gases to the atmosphere and is already industrially applied by use of chemical absorption with aqueous amines, as MonoEthanolAmine (MEA). This solvent is well performing, though being characterized by several drawbacks as high regeneration energy requirements, corrosion and toxicity. The excessive use of toxic solvents is environmentally detrimental and recognized as an unstable practice. In the efforts to address the issues of sustainability established in the 2030 Agenda for Sustainable Development, also the carbon dioxide absorption process is being studied and one key point is the employment of more environmentally friendly solutions. Aqueous amino acid salt solutions have been considered in the last years a viable alternative to traditional solvents for carbon dioxide removal. Moreover, some of them, such as the potassium taurate solvent, are characterized by precipitation at specific conditions during absorption, thus providing further advantages in terms of potential reduction in energy requirement to the process and/or costs. For any system, a validated process and thermodynamic model and simulation is one essential tool used by process engineers to assist with a thorough evaluation of different process options and designs. Choice of model parameters is fundamental to the accurate and reliable representation of the process. This work focuses on the analysis of the parameters influencing the rate-based simulation of the carbon dioxide removal section of a 500 MW coal-fired power plant. Results confirm that for the considered system the mass transfer coefficient is strongly influenced by the viscosity of the solvent and the diffusivity of CO₂ in the aqueous solution. The results also show that different values of the film discretization can lead to differences in the required solvent flowrate.