ENTHALPIES OF ABSORPTION AND SOLUBILITY OF CO2 IN AQUEOUS-SOLUTIONS OF METHYLDIETHANOLAMINE

A flow mixing unit using a SETARAM C-80 calorimeter, developed for mea suring the enthalpy of solution of two fluids, has been used to measur e enthalpies of absorption of carbon dioxide in a 30 wt.% aqueous solu tion of methyldiethanolamine (MDEA) at three temperatures 313.15, 353. 15, 393.15 K and three pressures 2.0, 5.0, 10.0 MPa. We have establish ed that the effect measured by calorimetry corresponds not only to the absorption of CO2 in the aqueous solution but also to the vaporisatio n of water into the carbon dioxide depending on the temperature and th e pressure of the experiment. The enthalpies measured by calorimetry w ere compared with those calculated from solubility measurements and a reasonable agreement within the accuracy of measurement and calculatio n was found. (C) 1997 Elsevier Science B.V.