Application of Molecular Modeling to Vapor-Liquid Equilibrium of Water with Synthesis Gas

Published

September 8, 2008

Author(s)

Allan H. Harvey

Abstract

In the Integrated Gasification Combined Cycle (IGCC) process for electricity generation, the hot synthesis gas may be quenched with water. The amount of water vaporized in this step has a large influence on the process economics, but is difficult to predict with typical thermodynamic models that are not designed for such systems. The most important factor in this phase-equilibrium problem is the nonideality of the vapor, which we model with the virial expansion. Second virial coefficients for water with synthesis gases are derived from state-of-the-art pair potentials obtained from quantum chemistry. When combined with Henry s law for the liquid phase, reliable results are obtained. Our results show that the vapor nonideality significantly enhances the water content of the vapor. Perhaps surprisingly, the Peng-Robinson equation, with a water-specific alpha function, is also able to provide reasonable values for the amount of water vaporized.

Proceedings Title

Proceedings of the 15th International Conference on the Properties of Water and Steam

Conference Dates

September 8-11, 2008

Conference Location

Berlin, GE

Pub Type

Conferences

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Keywords

carbon monoxide, carbon dioxide, hydrogen, IGCC, phase equilibrium, synthesis gas, thermodynamics, water

Citation

Harvey, A. (2008), Application of Molecular Modeling to Vapor-Liquid Equilibrium of Water with Synthesis Gas, Proceedings of the 15th International Conference on the Properties of Water and Steam, Berlin, GE, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=832264 (Accessed December 12, 2024)