THE SOLUBILITY OF CARBON DIOXIDE IN AQUEOUS SOLUTIONS OF N-METHYLDIETHANOLAMINE (MDEA) AND TRIETHYLENE TETRAMINE (TETA). 2. MODELING LA SOLUBILITE DU CO2 DANS DES SOLUTIONS AQUEUSES DE N-METHYLDIETHANOLAMINE (MDEA) ET TRIETHYLENE TETRAMINE (TETA). 2. MODE
JEAN-MARC AMANN, CHAKIB BOUALLOU* ECOLE NATIONALE SUPÉRIEURE DES MINES DE PARIS, CENTRE ÉNERGÉTIQUE ET PROCÉDÉS, 60 BOULEVARD SAINT MICHEL, 75006 PARIS, FRANCE *CORRESPONDING AUTHOR: CHAKIB.BOUALLOU@ENSMP.FR
A new solvent based on a blend of N-methyldiethanolamine (MDEA) and Triethylene Tetramine (TETA), an amine very reactive with CO2, was proposed for CO2 post-combustion capture in power plants. The new solubility data generated in our experimental work (Part I) were modelled with the Non Random Two Liquids (NRTL) electrolyte model. The chemical reactions used for the data regression are those relating to the H2O-MDEA-CO2 system and two reactions with TETA: amine dissociation and bicarbamate reversibility to bicarbonate. Objective function is of the Maximum likelihood type. Twenty-two parameters have been regressed on the whole experimental data: pressure, temperature, compositions of the liquid and gas phase (198 experimental points). These parameters are the reaction equilibrium constants of the chemical reactions including TETA, the binary interaction parameters between MDEA and TETA and the electrolytic interaction pair’s parameters relating to the NRTL electrolyte model. The average relative deviation on the pressure was calculated for each solvent. The deviation is acceptable, with a value ranging between 12.8 and 23.2%. For the solvent with the higher ratio between TETA concentration and MDEA concentration, the deviation is higher at 38.2%. The average and high pressures are well represented by the model. The error is more important at low CO2 loadings.
