The Volumetric Properties of Carbonyl Sulfide and Carbon Dioxide Mixtures from T = 322 to 393 K and p = 2.5 to 35 MPa: Application to COS Hydrolysis in Subsurface Injectate Streams

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• 作者：Connor E. Deering ; Matthew J. Saunders ; Jerry A. Commodore ; Robert A. Marriott
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2016
• 出版时间：March 10, 2016
• 年：2016
• 卷：61
• 期：3
• 页码：1341-1347
• 全文大小：351K
• ISSN：1520-5134

文摘

This work describes an exploration of high-pressure acid gas chemical equilibria in CO₂ rich fluids aimed at subsurface injection for acid gas reinjection, carbon sequestration, or enhanced oil recovery. To develop the capability to calculate both physical and chemical equilibria involving COS under high-pressure injectate conditions, we have measured the density changes associated with mixing COS (1) and CO₂ (2) at temperatures between T = 322.91 and 393.25 K and up to p = 35 MPa. These density differences were used to calculate apparent molar volumes for COS, which were used to calibrate binary mixing parameters for high-accuracy reduced Helmholtz energy equations-of-state (γ_ν,12 = 1.0496 and γ_T,12 = 0.94085). The new mixing parameters were shown to reproduce low-temperature p–x phase behavior measurements reported in the literature. The optimized mixing parameters were then applied in a Gibbs Energy Minimization (GEM) routine to find the enthalpy of formation for COS from literature equilibrium measurements at atmospheric conditions (Δ_fH^{298.15K,0.1 MPa} (COS) = 141.744 ± 0.803 kJ mol^–1). The same GEM routine was used to explore the reaction of acid gases at applicable high-pressures. Results showed a decreased reaction of H₂S + CO₂ at low-temperature and low-pressure, that is, COS hydrolysis is less favorable at high-pressure.