Quantitative understanding of the water content of pipeline fluids in equilibrium with hydrates is critically important to ensure pipeline flow without hindrance from solid precipitation. This paper focuses on pipelines with CO 2 -rich fluids in cold environments (such as those in Alaska) and generally in CO 2 capture. Since there is considerable question about the available data for the water solubility in CO 2 at these conditions, a round-robin testing program was structured by Fluor/Worley Parsons Arctic Solutions to quantitatively establish the water solubility. The goal of the data program was to determine the water solubility in CO 2 -rich mixtures to estimated uncertainty. This paper presents the data program and evaluates its results through thermodynamic analysis and comparison to available literature data.
We report liquid−liquid mutual solubilities for binary aqueous mixtures involving 2-, 3-, and 4-ethylphenol, 2-, 3-, and 4-methoxyphenol, benzofuran, and 1H-indene for the temperature range (300 < T/K < 360). Measurements in the waterrich phase for (2-ethylphenol + water) and (4-ethylphenol + water) were extended to T = 440 K and T = 380 K, respectively, to facilitate comparison with literature values. Liquid−liquid equilibrium tie-line determinations were made for four ternary systems involving (water + toluene) mixed with a third component: phenol, 3-ethylphenol, 4-methoxyphenol, or 2,4-dimethylphenol. Literature values at higher temperatures are available for the three (ethylphenol + water) systems, and in general, good agreement is seen. The ternary system (water + toluene + phenol) has been studied previously with inconsistent results reported in the literature, and one report is shown to be anomalous. All systems are modeled with the predictive methods NIST-modified-UNIFAC and NIST-COSMO-SAC, with generally good success (i.e., within 0.05 mole fraction) in the temperature range of interest (300 < T/K < 360). This work is part of a larger project on the testing and development of predictive phase equilibrium models for compound types occurring in catalytic fast pyrolysis of biomass, and background information for that project is provided.
Vapor−liquid equilibrium (VLE) measurements have been performed on several binary systems incorporating chemicals of interest to the biofuels industry. Systems were chosen based on two criteria: (1) similarity to measurement requests received by Wiltec and (2) suitability of using the Wilson Equation to model the activity coefficients for the VLE data. The Wilson Equation is a good choice for modeling fully miscible solutions of moderately polar compounds. With these two ideas in mind, systems were chosen incorporating the following compounds: 1-methoxy-2-propanol, 2-furaldehyde, allyl alcohol, butyl acetate, carbon dioxide, carbon disulfide, carbonyl sulfide, ethanolamine, ethyl acetate, n-butanol, pentane, and tert-butanol. Measurement temperatures ranged from −25 °C to +200 °C.
A liquid/vapor isotherm model is developed by application of the ideal adsorbed solution theory (IAST) to liquid-phase excess adsorption data. The surface adsorption of mixtures is treated with IAST based on Langmuir isotherms on a fugacity basis. The mixture surface adsorption predictions are then directly related to experimental liquid excess adsorption measurements through mass balance. Excess adsorption measurements of several hydrocarbons on silica gel are performed, which allow for the extraction of the unary Langmuir isotherm parameters. The unary basis of the parameters allows for predictability in a wide range of mixtures. This methodology provides a novel and unified description of complex mixture adsorption from both vapors and liquids. The approach is then extended to petroleum pseudocomponents. From this petroleum representation, we demonstrate the accurate prediction of vapor and liquid adsorption data for species that were not included in the model development.
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