scholarly journals Evaluation of Different Correlation Performance for the Calculation of the Critical Properties and Acentric Factor of Petroleum Heavy Fractions

2018 ◽  
Author(s):  
Dacid B. Lacerda ◽  
Rafael B. Scardini ◽  
André P. C. M. Vinhal ◽  
Adolfo P. Pires ◽  
Viatcheslav I. Priimenko
Keyword(s):  
Critical Properties ◽  
Acentric Factor ◽  
Heavy Fractions ◽  
Correlation Performance

Correlation of critical properties and acentric factor of hydrocarbons and derivatives

AIChE Journal ◽  
1984 ◽  
Vol 30 (6) ◽  
pp. 981-983 ◽  
Author(s):  
Ho-Mu Lin ◽  
Kwang-Chu Chao
Keyword(s):  
Critical Properties ◽  
Acentric Factor

Evaluation of Optimal Methods for Critical Properties and Acentric Factor of Biodiesel Compounds with Their Application on Soave–Redlich–Kwong and Peng–Robinson Equations of State

2015 ◽  
Vol 60 (11) ◽  
pp. 3358-3381 ◽  
Author(s):  
Frederico R. do Carmo ◽  
Nathan S. Evangelista ◽  
Fabiano A. N. Fernandes ◽  
Hosiberto B. de Sant’Ana
Keyword(s):  
Equations Of State ◽  
Critical Properties ◽  
Acentric Factor ◽  
Optimal Methods

Critical Properties, Normal Boiling Temperature, and Acentric Factor of Another 200 Ionic Liquids

2008 ◽  
Vol 47 (4) ◽  
pp. 1318-1330 ◽  
Author(s):  
José O. Valderrama ◽  
Wilson W. Sanga ◽  
Juan A. Lazzús
Keyword(s):  
Ionic Liquids ◽  
Boiling Temperature ◽  
Critical Properties ◽  
Acentric Factor

Effect of C7+ Properties on Equation-of-State Predictions

1984 ◽  
Vol 24 (06) ◽  
pp. 685-696 ◽  
Author(s):  
Curtis H. Whitson
Keyword(s):  
Specific Gravity ◽  
Boiling Point ◽  
Binary Interaction ◽  
Critical Properties ◽  
Critical Property ◽  
Interaction Coefficients ◽  
Acentric Factor ◽  
Pvt Data ◽  
Petroleum Fractions ◽  
Property Correlations

Summary This work studies the effect of heptanes-plus (C7+) characterization on equation-of-state (EOS) predictions. Both the Peng-Robinson EOS (PREOS) and a modified Redlich-Kwong EOS are used. Several characterization schemes found in the literature are used in the study. Six reservoir fluids with extended C7+ analysis have been chosen, representing a broad range of compositions and PVT data. First, the study deals with methods for estimating specific gravities and boiling points of petroleum fractions, two properties usually required by critical property correlations. EOS predictions are made by using critical properties based on specific gravities and boiling points measured experimentally and estimated with correlations. Next, a review of critical-property correlations is given, including a review of commonly used correlations. Four correlations are chosen to study the effect of critical properties on EOS predictions. Results indicate that relatively small differences in critical properties and acentric factor can result in significant differences in EOS predictions. Finally, a study is made of the effect that adjustments in C7+ critical properties have on EOS predictions; adjustments of EOS constants (Oa and Ob) and binary interaction coefficients also are studied. The influence of individual and combined adjustments to C7+ properties are illustrated graphically. They provide qualitative guidelines that can be used when matching experimental PVT data with an EOS. Introduction Recently there has been an increasing interest in EOR methods. One result has been the need to develop numerical models for simulating EOR processes involving complex phase behavior. Most of these models use an EOS to predict vapor/liquid equilibrium (VLE) and volumetric phase behavior. A typical problem with using an EOS is the difficulty in describing petroleum fractions constituting C7+. These fractions significantly affect EOS predictions, as has been reported in the literature. Usually only limited C7+ data are available to describe C7+ fractions. Even so, estimates of critical properties - critical pressure, critical temperature, and acentric factor - are required by most EOS's. Several correlations exist for estimating critical properties of petroleum fractions. Most are empirical equations giving a best fit of graphical correlations based on experimental data. Boiling point and specific gravity usually are required by critical property correlations. Several methods exist for estimating specific gravity and boiling point of petroleum fractions when only C7+ properties are known. Four of these have been used in our study. Several methods have been tried to improve C7+ characterization by approximating the chemical makeup of petroleum fractions. The most common approach assumes that petroleum fractions are composed of three hydrocarbon groups: paraffins (P), naphthenes (N), and aromatics (A). Several methods exist for estimating PNA content of petroleum fractions. 1–3 Three aspects of C7+ characterization have been studied:methods for estimating specific gravity and boiling point of petroleum fractions,correlations for estimating critical pressure, critical temperature, and acentric factor, andmanual adjustment of critical properties, EOS constants (Oa and Ob), and binary interaction coefficients (particularly between methane/CO2 and C7+ fractions). Reservoir fluids used in this study were chosen on the basis of availability of distillation data for C7+ fractions and the type of PVT measurements reported. Six fluids have been chosen from the literature, including fluids ranging from a lean gas to a black oil. PVT measurements have been reported at more than one temperature for some of the mixtures, which allows the study of temperature dependence of binary interaction coefficients between methane and C7+ fractions. Two cubic EOS's are used to make PVT predictions. PREOS4 was chosen because it is widely accepted in the industry and it generally yields better liquid-density estimates than the comparable Soave-Redlich-Kwong5 (SRK) equation. As a representative of the Redlich-Kwong6 family, Yarborough's7 version of the modified Zudkevich-Joffe-Redlich-Kwong8 (ZJRK) equation was chosen. Results from this work suggest that C7+ characterization has a significant influence on EOS predictions of reservoir fluid behavior. It is difficult to make objective conclusions about which C7+ characterization schemes are best. A different approach to characterization is needed. One possible alternative would be to calculate critical properties of petroleum fractions such that measured values of specific gravity and boiling point are force-fit by the EOS.

scholarly journals Fatty Acid Content in Biomasses: State-of-the-Art and Novel Physical Property Estimation Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-25
Author(s):  
Ana M. Sousa ◽  
Thalles A. Andrade ◽  
Massimiliano Errico ◽  
José P. Coelho ◽  
Rui M. Filipe ◽  
...  
Keyword(s):  
State Of The Art ◽  
Fatty Acid Content ◽  
Physical Property ◽  
Simulation Software ◽  
Biofuel Production ◽  
Estimation Methods ◽  
Critical Properties ◽  
Acentric Factor ◽  
Average Deviation ◽  
Property Estimation

In line with the growing environmental awareness developed along the last decades, modern societies are urged to evolve into sustainable economics where the reuse of organic wastes represents the key feedstock for a green transaction. The oil phase obtained from different biomasses has the potential to be a source of food supplements, medicines, cosmetics, or feedstock for biofuel production. In the present work, the composition of 104 different biomasses including seeds, peels, flowers, plants, and leaves has been reviewed for the lipid content. Based on the most frequent fatty acids screened, experimental data for normal boiling point temperature, normal melting point, critical properties, and acentric factor were collected and compared with the most common estimation methods, which are functions of the molecular structure and interaction between different functional groups. New predictive equations have been proposed to reduce the estimation deviation and to provide simple correlations to be used in simulation software when dealing with biomass processes. For all the properties, the estimations proposed have an absolute average deviation equal to or lower than 4.6%.

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