Application of Absorption by Potassium Taurate Solutions to Post-combustion CO2 Removal from Flue Gases with Different Compositions and Flowrates

Abstract

Climate change issues have led many countries to actively participate to international conventions, with the aim of reducing the impact of human activities on the environment. In this framework the Paris Agreement has established to keep the temperature rise below 2°C above the pre-industrial level.
One suitable mitigation option is to remove carbon dioxide, before it is emitted into the atmosphere. Several technologies are available, including chemical processes where acid gases are absorbed by aqueous alkanolamines solutions. Although this process is already widely used in industry, these solvents are characterized by high energy requirements, in addition to other disadvantages such as corrosion and degradation. Recently, alternative solvents are being studied as possible substitutes for traditional amine solutions. Precipitating solvents are considered in chemical absorption processes because of their characteristic of forming a solid phase, which allows the removal of one reaction product from the liquid solution, therefore shifting the equilibrium of the reaction and so enhancing the mass transfer of the CO₂ from the vapor phase to the liquid phase. One class of precipitating solvents are amino acids, with several different types which can be used in aqueous solution. Previous studies have identified the most suitable types for the capture of carbon dioxide and have highlighted the additional advantages of low corrosion and high stability towards degradation, in particular for the amino acid species containing a sulfonic group, such as taurine.
This work focuses on the use of potassium taurate aqueous solutions for the removal of carbon dioxide from flue gases from natural gas and coal-fired power plants. The aim is to evaluate changes in the solvent performance arising from changes in the flue gases composition and flowrates.
The obtained results confirm the possible application of the potassium taurate aqueous solution for CO₂ removal both in coal-fired and in NGCC power plants, with different energy requirements.