Enthalpies of solution of carbon dioxide in aqueous diglycolamine solutions

Abstract

An isothermal flow calorimeter was used to measure the enthalpies of solution of carbon dioxide in aqueous 10, 20, 40, and 60 wt.% diglycolamine (DGA) solutions. The experimental temperature and pressure ranges were 288.71-422.04 K and 156-1121 kPa, respectively. The experimental equipment and procedure are described, with emphasis on peculiarities originating from the difficulty of measuring the enthalpy of solution of a gas in a liquid. The calorimetric data were also found to be useful in determining the equilibrium concentrations of CO2 in the DGA solutions. Both enthalpy of solution and equilibrium concentration data for CO2 -aqueous DGA systems are reported and compared with existing values from other investigations. The enthalpy of solution of CO2 in aqueous DGA solutions was found to be independent of temperature and pressure and linearly dependent on the concentration of DGA in solution. An equation is given for predicting the enthalpy of solution over the ranges of temperatures, pressures, and concentrations investigated. © 1986.