A new investigation of wax precipitation in Iranian crude oils: Experimental method based on FTIR spectroscopy and theoretical predictions using PC-SAFT model

Meighani, H. Mashhadi; Ghotbi, Cyrus; Behbahani, Taraneh Jafari; Sharifi, Khashayar

doi:10.1016/j.molliq.2017.11.110

Cited by 23 publications

(4 citation statements)

References 32 publications

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“…The database used in this research work was described earlier in this text (Tables and ). This database is collected from 27 experimental research works − reporting 1439 data samples for 39 different oil samples. Before applying the statistical preprocessing, some amendments were performed on the database.…”

Section: Methodsmentioning

confidence: 99%

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Connectionist Models for Asphaltene Precipitation Prediction by n-Alkane Titration─Pressure and Crude Oil Properties Considered

Tatar,

Shafiei

2023

Ind. Eng. Chem. Res.

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Experimental approaches for determining asphaltene precipitation in a laboratory are time-consuming and expensive due to consumption of a large amount of solvents. Development of robust, reliable, fast, and economic predictive tools to forecast the amount of asphaltene precipitation for a wide range of pressures, temperatures, and operational parameters and properties of petroleum fluids is inevitable. The main objective of this research work was to develop machine learning models using experimental data to predict asphaltene precipitation amount due to titration. After collecting 1439 data samples from 27 experimental research works, a quality check was performed for possible logical filling of the missing values and detecting the problematic data samples. Three categories, operational parameters, oil properties, and gas properties, were recognized to be the most influential parameters. The database used in this work is so far the largest ever reported in the literature. In addition, pressure is considered as one of the major parameters in this work, which was not considered in the previously reported models (i.e., all were conducted under ambient pressure). For the first time, 39 different oil samples were considered in the modeling (i.e., the existing works are mostly for one oil sample). We proposed new indices in the modeling to account for different oil types and n-alkanes. Due to the pressure data distribution, the database was split into two clusters. Each cluster went through several statistical preprocessing stages including treating duplicates and zero-variance features, imputing the missing data, assessing the collinearity, feature selection, and data splitting and scaling. Then, five different models, multilayer perceptron (MLP), support vector machine (SVM), decision tree (DT), random forest (RF), and committee machine intelligent system (CMIS), were used for model development. Based on the acquired results, the RF was determined as the best predictor for both clusters, consequently, for the whole database with root-mean-square error (RMSE) and R 2 values of 0.94 and 0.97, respectively, for the testing data set. The developed models can be used to accurately predict asphaltene precipitation by n-alkane titration for a wide range of pressure and crude oil properties.

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Section: Methodsmentioning

confidence: 99%

“…A thorough literature review was performed to locate the experimental works performed on this topic. In this regard, 27 experimental research works − were found reporting 1439 data samples. The number of research works and reported data samples is shown in Figure .…”

Section: Introductionmentioning

confidence: 99%

Connectionist Models for Asphaltene Precipitation Prediction by n-Alkane Titration─Pressure and Crude Oil Properties Considered

Tatar,

Shafiei

2023

Ind. Eng. Chem. Res.

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“…The orthorhombic form is needle-shaped, and it is found in crudes with high waxy content [15,16]. Crystallization kinetics and crystal morphology can be highly affected by some recognized factors, such as cooling rate [13,[17][18][19][20][21][22][23], carbonic chain nature (branched or linear and average length) [21], resins and asphaltene content [2,7,24,25], and shear rate [16,[26][27][28].…”

Section: Morphological Characterizationsmentioning

confidence: 99%

Wax Chemical and Morphological Investigation of Brazilian Crude Oils

Chrisman¹,

Duncke²,

Oliveira³

et al. 2020

Paraffin - An Overview

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The waxes in petroleum can precipitate and form unwanted gels and deposition when exposed to low temperatures. The idea of this chapter is to approach methods of quantification and physicochemical and morphological characterization of waxes and how this information can help in understanding this deposition. Information such as the quantity of waxes and the chemical structures in the oil is fundamental to predict the possible deposition and its ability to aggregate with other crystals. For example, the knowledge about the wax morphology may contribute to explain the nucleation and growth of the deposits. The polarized light microscopy, the most common technique to visualize wax crystals, and the brightfield microscopy, the most simple technique, able to show crystal details that have not been seen on the polarized light, was used.

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“…This approach was applied to WAT measurements of asphalt binders 39,40 and crude oil. 41 For these measurements, the thin film method was used, where the sample was placed between two NaCl (KBr) windows, the windows were placed in a cell holder with variable temperature capability, and the IR spectra were recorded in transmission mode.…”

Section: Introductionmentioning

confidence: 99%

Features of Wax Appearance Temperature Determination of Waxy Crude Oil Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Under Ambient and High Pressure

Shalygin,

Kozhevnikov,

Morozov

et al. 2023

Appl Spectrosc

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The wax appearance temperature (WAT), being one of the key characteristics of waxy crude oil and other waxy substances, is used for the necessary assessment of the phase stability of materials during various technological processes. However, the determination of this parameter as well as peculiarities of wax formation under high gas pressure suffers from the lack of suitable techniques for this task. To address this issue, an attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) method has been applied for the first time to measure the WAT of waxy crude oil under high gas pressure. Carbon dioxide (CO2), nitrogen, and natural gas were used in the study due to their widespread applicability as injection gases in enhanced oil recovery methods. The S2/S1 versus temperature method based on changes in the band of rocking vibrations of the CH2 group was applied to determine WAT. It was found that the ATR FT-IR method based on the proposed dependence S2/S1 versus temperature gives lower WAT values compared to those observed by viscometry, magnetic resonance imaging inspection, and cross-polarized microscopy methods for the waxy crude oil studied. A detailed analysis was carried out using variable-temperature ATR FT-IR spectra of waxy crude oil in the temperature region near the WAT. Essentially different dynamics of wax crystal formation in waxy oil sample and model paraffin solution were demonstrated during the cooling process. The results obtained by high-pressure ATR FT-IR showed that CO2 and natural gas reduce the WAT, while nitrogen has virtually no effect. In addition, for the studied oil, it was found that high pressure of CO2 and natural gases leads to a visual decrease in the amount of wax crystals precipitated, but not to the complete disappearance of microcrystals at a certain temperature and pressure. The results obtained proved that ATR FT-IR can be an effective method for proper determinations of WAT under high-pressure conditions similar to those met in practice.

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A new investigation of wax precipitation in Iranian crude oils: Experimental method based on FTIR spectroscopy and theoretical predictions using PC-SAFT model

Cited by 23 publications

References 32 publications

Connectionist Models for Asphaltene Precipitation Prediction by n-Alkane Titration─Pressure and Crude Oil Properties Considered

Connectionist Models for Asphaltene Precipitation Prediction by n-Alkane Titration─Pressure and Crude Oil Properties Considered

Wax Chemical and Morphological Investigation of Brazilian Crude Oils

Features of Wax Appearance Temperature Determination of Waxy Crude Oil Using Attenuated Total Reflection Fourier Transform Infrared Spectroscopy Under Ambient and High Pressure

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