The Effect of Monoethylene Glycol on Calcium Carbonate Solubility at High Temperatures

Abstract

Copyright © 2018 American Chemical Society. This study presents the solubility of calcium carbonate in monoethylene glycol (MEG)/water solution at high temperatures and high MEG concentrations. The conditions simulate the water removal process during MEG regeneration. Solubility was measured by dissolution at equilibrium, and the thermodynamics of the dissolution process of calcium carbonate was also explored. The solubility of calcium carbonate decreased with increasing temperature up to 120 °C and showed a slight increase above 120 °C. The presence of MEG increased the activity coefficient of calcium carbonate and calcium ions with respect to temperature. The effect of MEG degradation on the solubility of calcium carbonate was also studied. At all temperatures studied (90 to 145 °C), MEG degraded in the presence of residual dissolved oxygen to produce acetate ions which complexed with calcium ions resulting in an increase in calcium solubility.