Densities and isobaric heat capacities at high pressures of aqueous solutions of 2-diethylaminoethanol (DEAE) or 2-ethylaminoethanol (EAE) for CO2 capture

Abstract

Densities and isobaric heat capacities of DEAE + H2O and EAE + H2O systems are presented in this paper. Density measurements were carried out at high pressure (up to 100 MPa) and temperatures from (293.15 to 393.15) K, with amine mass fractions of 0.1; 0.2; 0.3 and 0.4. These data were gathered using a vibrating tube densimeter (Anton Paar DMA HPM) with a relative expanded uncertainty of ±0.1 % (k = 2). A non-adiabatic quasi-isothermal flow calorimeter was used for isobaric heat capacity measurements with a relative expanded uncertainty better than 1 % (k = 2). Measurements reached pressures up to 25 MPa, and temperatures from (293.15 to 353.15) K, with amine mass fractions of 0.1; 0.2; 0.3 and 0.4. Both amine DEAE + H2O and EAE + H2O systems show a density and isobaric heat capacity decrease with amine mass fraction increase. Density data as a function of temperature, pressure and molality were fitted using a modified Tammann-Tait empirical equation of state. Furthermore, isobaric heat capacity data were correlated using an empirical function of temperature and amine mass fraction, but not pressure due to its lack of sensitivity in the measured data. Both correlations are in good agreement with the uncertainties. Comparison with experimental density data available in literature showed lower deviations than the associated uncertainties. Our isobaric heat capacity experimental data agree well with the scarce literature.