Novel Physical Solvents for Selective CO2 Capture from Fuel Gas Streams at Elevated Pressures and Temperatures

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• 作者：Yannick J. Heintz ; Laurent Sehabiague ; Badie I. Morsi ; Kenneth L. Jones ; Henry W. Pennline
• 刊名：Energy & Fuels
• 出版年：2008
• 出版时间：November 19, 2008
• 年：2008
• 卷：22
• 期：6
• 页码：3824-3837
• 全文大小：519K
• 年卷期：v.22,no.6(November 19, 2008)
• ISSN：1520-5029

文摘

Three perfluorinated compounds (PFCs), PP10, PP11, and PP25, manufactured by F2 Chemicals Ltd., U.K., were investigated as physical solvents for selective CO₂ capture from synthesis gas or syngas streams at elevated pressures and temperatures. The equilibrium solubility, the hydrodynamic, and the mass-transfer parameters of CO₂ in the solvents were measured in a 4-L ZipperClave agitated reactor under wide ranges of operating conditions: pressures (6−30 bar), temperatures (300−500 K), mixing speeds (10−20 Hz), and liquid heights (0.14−0.22 m). The CO₂ solubilities in the three solvents decreased with an increasing temperature at constant pressure and followed Henry’s law. The CO₂ solubilities in PP25 were greater than those in PP10 and PP11. The volumetric liquid-side mass-transfer coefficients (k_La) of CO₂ in the PFCs increased with mixing speed, pressure, and temperature. Also, the gas−liquid interfacial areas of CO₂ in the three PFCs appeared to control the behavior of k_La. This study proved the thermal and chemical stability and the ability of the PFCs to selectively absorb CO₂ at temperatures up to 500 K and pressures as high as 30 bar. A preliminary conceptual process design using PP25 for selective CO₂ capture from hot-shifted gas with pressure-swing and pressure−temperature-swing regeneration options was devised [a temperature-swing option was also examined but is not reported here because it is outside the context of the present study, which involves a physical solvent process benchmark (Selexol) for which temperature-swing regeneration is not a viable option]. The pressure−temperature-swing option led to greater PP25 solvent loss but a more favorable (more negative) net enthalpy than the pressure-swing option. However, for either regeneration option to be economically viable, the PP25 solvent must be completely recovered from the process.