Reactive Phase Equilibria in Silica Aerogel Synthesis:  Experimental Study and Prediction of the Complex Phase Behavior Using the PC-SAFT Equation of State

Abstract Phase equilibria data were used to develop an equation-of-state correlation for complex hydrocarbon mixtures, thereby circumventing difficulties associated with use of pressure-volume-temperature data. Equilibrium phase data for two condensate reservoir fluids were used to determine equation-of-state parameters for hydrocarbons as heavy as C22H46 in a modified form of the Benedict-Webb-Rubin equation of state. Comparative tests of K-values from the resultant correlation were made with data for condensate reservoir, separator and gas plant absorber mixtures. Generally, for temperatures above 0F and computed liquid densities below 0.55 lb-mole/cu ft, the modified BWR equation predicted K-values in close agreement with the experimental data. Introduction Accurate predictions of thermodynamic behavior for complex hydrocarbon mixtures are necessary for many calculations k the petroleum industry. Because of the relatively high cost of extensive experimental data, many correlations for prediction of phase behavior have been developed. Some of these, such as the correlation of K-values presented in the NGAA Equilibrium Ratio Data Book, are totally empirical. Others, such as the Benedict-Webb-Rubin (BWR) equation-of-state method, are semitheoretical. Unfortunately, published correlation methods often do not accurately predict the phase behavior of complex hydrocarbon mixtures, principally because of inadequate representation of the effects of components heavier than decane. This paper presents a new approach to this problem in which basic equation-of-state relations including heavy hydrocarbon effects are applied. Equilibrium phase data for two condensate reservoir fluids containing hydrocarbons as heavy as C22H46 are used to correlate component K-values. The BWR equation was chosen as the prototype equation of state for this study because of its proven capability for accurately predicting phase behavior and thermodynamic properties of light-hydrocarbon mixtures. Research was directed toward development of BWR parameters for the heavy hydrocarbons and modifications of the mathematical form of the BWR equation for application to complex hydrocarbon mixtures. The new equation-of-state approach presented differs considerably from previous methods in that phase equilibria rather than PVT data are used for determination of equation-of-state parameters. It is an explicit approach since the parameters are determined directly from mixture data. As such, it does not encounter problems inherent in the implicit method used by Benedict, Webb and Rubin and numerous other investigators-one in which mixture parameters were postulated to be functions of the pure component parameters. The pure component BWR parameters, in turn, were determined from experimental PVT data. This method has been limited to mixtures containing components lighter than decane because of lack of vapor phase PVT data. Studies have been reported in which BWR parameters have been determined explicitly from PVT data for binary mixtures. However, since small concentrations of heavier components have only a minor effect on PVT behavior, it is doubtful that these explicit methods would yield useful results for condensate systems. Ellington and Eakin have shown that the accuracy of K-values predicted by an equation of state developed from mixture PVT data probably would be more than an order of magnitude lower than the accuracy of the PVT data. On the other hand an equation of state utilizing parameters developed from phase equilibria data should predict K-values with accuracy comparable to be accuracy of the experimental phase compositions. This work applies this explicit approach with the objective of improving hydrocarbon mixture phase behavior predictions. SPEJ P. 363ˆ

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Preparation and experimental study on the thermal characteristics of lightweight prefabricated nano-silica aerogel foam concrete wallboards

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.121895 ◽

2021 ◽

Vol 272 ◽

pp. 121895

Author(s):

Peng Liu ◽

Yan Feng Gong ◽

Guo Hua Tian ◽

Zheng Kun Miao

Keyword(s):

Experimental Study ◽

Silica Aerogel ◽

Thermal Characteristics ◽

Nano Silica ◽

Foam Concrete

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Revisiting Kelvin equation and Peng–Robinson equation of state for accurate modeling of hydrocarbon phase behavior in nano capillaries

Scientific Reports ◽

10.1038/s41598-021-86075-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ilyas Al-Kindi ◽

Tayfun Babadagli

Keyword(s):

Experimental Data ◽

Surface Tension ◽

Equation Of State ◽

Phase Behavior ◽

Pore Radius ◽

Microfluidic Chips ◽

Tight Sandstone ◽

Kelvin Equation ◽

Rock Samples ◽

Robinson Equation

AbstractThe thermodynamics of fluids in confined (capillary) media is different from the bulk conditions due to the effects of the surface tension, wettability, and pore radius as described by the classical Kelvin equation. This study provides experimental data showing the deviation of propane vapour pressures in capillary media from the bulk conditions. Comparisons were also made with the vapour pressures calculated by the Peng–Robinson equation-of-state (PR-EOS). While the propane vapour pressures measured using synthetic capillary medium models (Hele–Shaw cells and microfluidic chips) were comparable with those measured at bulk conditions, the measured vapour pressures in the rock samples (sandstone, limestone, tight sandstone, and shale) were 15% (on average) less than those modelled by PR-EOS.

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Phase equilibria modeling of biorefinery-related systems: a systematic review

Chemical Product and Process Modeling ◽

10.1515/cppm-2020-0119 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Marcos L. Corazza ◽

Julia Trancoso

Keyword(s):

Phase Equilibria ◽

Phase Behavior ◽

Fossil Fuel ◽

Process Conditions ◽

Design And Optimization ◽

Waste Reuse ◽

Wide Range ◽

Prisma Statement ◽

Fuel Substitution ◽

The Subject

Abstract The search for sustainable ideas has gained prominence in recent decades at all levels of society since it has become imperative an economic, social, and environmental development in an integrated manner. In this context, biorefineries are currently present as the technology that best covers all these parameters, as they add the benefits of waste reuse, energy cogeneration, and fossil fuel substitution. Thus, the study of the various applicable biological matrices and exploring the technical capabilities of these processes become highly attractive. Thermodynamic modeling acts in this scenario as a fundamental tool for phase behavior predictions in process modeling, design, and optimization. Thus, this work aimed to systematize, using the PRISMA statement for systematic reviews, the information published between 2010 and 2020 on phase equilibria modeling in systems related to biorefineries to organize what is already known about the subject. As a result, 236 papers were categorized in terms of the year, country, type of phase equilibria, and thermodynamic model used. Also, the phase behavior predictions of different thermodynamic models under the same process conditions were qualitatively compared, establishing PC-SAFT as the model that best represents the great diversity of interest systems for biorefineries in a wide range of conditions.

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Pore-Scale Simulation of Confined Phase Behavior with Pore Size Distribution and Its Effects on Shale Oil Production

Energies ◽

10.3390/en14051315 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1315

Author(s):

Jingwei Huang ◽

Hongsheng Wang

Keyword(s):

Phase Equilibrium ◽

Equation Of State ◽

Pore Size Distribution ◽

Phase Behavior ◽

Pore Size ◽

Size Distribution ◽

Critical Role ◽

Shale Oil ◽

Pore Scale ◽

Modified Equation

Confined phase behavior plays a critical role in predicting production from shale reservoirs. In this work, a pseudo-potential lattice Boltzmann method is applied to directly model the phase equilibrium of fluids in nanopores. First, vapor-liquid equilibrium is simulated by capturing the sudden jump on simulated adsorption isotherms in a capillary tube. In addition, effect of pore size distribution on phase equilibrium is evaluated by using a bundle of capillary tubes of various sizes. Simulated coexistence curves indicate that an effective pore size can be used to account for the effects of pore size distribution on confined phase behavior. With simulated coexistence curves from pore-scale simulation, a modified equation of state is built and applied to model the thermodynamic phase diagram of shale oil. Shifted critical properties and suppressed bubble points are observed when effects of confinement is considered. The compositional simulation shows that both predicted oil and gas production will be higher if the modified equation of state is implemented. Results are compared with those using methods of capillary pressure and critical shift.

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