Thermophysical properties of fresh and lean thermally degraded N-methyldiethanolamine

•Thermophysical properties for thermally degraded MDEA solutions were investigated.•The measured values were validated through comparison with literature data.•Correlations of thermophysical properties were depicted.•The relative deviation between predicted and experimental data ranged from 3.5% to 7.5%.

This paper gives a deep insight to the thermophysical properties for thermally degraded methyldiethanolamine (MDEA) solutions. Density, viscosity and surface tension of samples of fresh MDEA solutions, real lean MDEA solutions, and thermally degraded MDEA solutions were measured at different temperatures. The measured values were validated through comparison with literature data. The obtained results were used to produce correlations for MDEA solution density and viscosity as a function of initial amine concentration, degradation time, and temperature. Increasing the degradation time and temperature increased the density, viscosity and surface tension. The predicted concentrations of MDEA of real lean amine samples were compared with the measured values through acid-base titration. The relative deviation between the results of titration and the predicted ones by the developed correlations ranged from 3.5% to 7.5%.