Title: The solubility of hydrogen sulfide in aqueous N-methyldiethanolamine solutions

Authors: P.J.G. Huttenhuis, N.J. Agrawal, G.F. Versteeg

Addresses: Procede Group B.V. P.O. Box 328, 7500 AH, Enschede, The Netherlands. ' Procede Group B.V. P.O. Box 328, 7500 AH, Enschede, The Netherlands. ' Procede Group B.V. P.O. Box 328, 7500 AH, Enschede, The Netherlands

Abstract: In this work the electrolyte equation of state as developed previously for the system MDEA-H₂O-CO₂-CH₄ [Huttenhuis et al. (2008), pp.99-112] was further developed for the system MDEA-MDEA-H₂O-H₂S-CH₄. With this thermodynamic equilibrium model the total solubility of hydrogen sulfide and the speciation in aqueous solutions of N-methyldiethanolamine can be described quantitatively. The model results were compared to experimental H₂S solubility data in aqueous MDEA in absence and presence of methane respectively. The application of equation of state models for this kind of acid gas – amine systems is a rather new development in the literature. An accurate description is difficult for this kind of complex systems with significant amount of both molecular and ionic species present in the liquid phase. The Schwarzentruber|s modification of the Redlich-Kwong-Soave EOS with a Huron-Vidal mixing rule is used as molecular part of the equation of state and ionic interactions terms are added to account for non-idealities caused by these interactions. With the new developed model a comparison with experimental data as presented was made. [Received: February 11, 2008; Accepted: June 1, 2008]

Keywords: hydrogen sulfide; N-methyldiethanolamine; solubility; electrolyte equation of state; gas treating; aqueous solutions.

DOI: 10.1504/IJOGCT.2008.020370

International Journal of Oil, Gas and Coal Technology, 2008 Vol.1 No.4, pp.399 - 424

Published online: 19 Sep 2008 *

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