A modified thermodynamic modeling of wax precipitation in crude oil based on PC-SAFT model

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

doi:10.1016/j.fluid.2016.09.010

Cited by 14 publications

(5 citation statements)

References 30 publications

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“…With the decrease in onshore and offshore oil and gas resources, the development of global oil and gas resources in deep water will replace strategic regional oil and gas resources [1,2]. The deep-water environment not only has strict requirements for platforms, subsea production systems and offshore work, but also poses serious challenges in terms of the length of submarine pipeline, ranging from a few kilometers to hundreds of kilometers, required to connect each satellite well, marginal oilfield and central processing facility [3,4]. Due to the low-temperature environment of the seabed (deep-sea seabed temperature is approximately 4 • C) [5], when crude oil is extracted from reservoir flows through submarine mixed-transmission pipelines, the crude oil temperature near the pipe wall drops below the wax appearance temperature (WAT), and wax molecules dissolved in the crude oil near the pipe wall crystallize and deposit on the pipe wall or form an immobile layer due to the free surface energy.…”

Section: Introductionmentioning

confidence: 99%

Experimental Measurements of Wax Precipitation Using a Modified Method of Simultaneous Centrifugation and High-Temperature Gas Chromatography

Liu

Duan

et al. 2021

Energies

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Wax precipitation and deposition are serious flow assurance problems. Wax precipitation is investigated simultaneously using centrifugation and high-temperature gas chromatography (C-HTGC) to obtain the amount and component distribution of precipitated wax in artificial waxy oil and diesel at different temperatures. However, the conventional C-HTGC method gives upper measurements of the amount of precipitated wax, as it ignores wax dissolved in crude oil in the centrifugal cake. A modified C-HTGC method was developed to obtain the precipitated solid fraction of crude oil, based on the mass balances of the non-crystallized fraction of the centrifuged cake. The weight, percent and carbon number distribution of precipitated solid wax crystals at different temperatures of artificial oil and 0# diesel were obtained. It was found that wax precipitation characteristics are affected by many factors, including the carbon number distribution of the oil, the sensitivity of alkane crystallization to temperature and the temperature of the waxy oil solution. The average carbon number of alkanes in precipitated wax crystals decreases with the decrease in temperature. The distribution of alkanes in solid wax crystals is roughly the same as that in 0# diesel but slightly heavier than in diesel. Alkanes with high carbon numbers precipitate simultaneously with those with low carbon numbers.

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Section: Introductionmentioning

confidence: 99%

Experimental Measurements of Wax Precipitation Using a Modified Method of Simultaneous Centrifugation and High-Temperature Gas Chromatography

Liu

Duan

et al. 2021

Energies

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“…The AAD of 0.3−0.8% was reported in this work. 14 Bagherinia et al improved the wax precipitation approach using the PC-SAFT EOS for the calculation of the vapor and liquid phase's fugacities and the UNIQUAC equation for evaluating the activity coefficient in the solid phase. The obtained absolute average deviation indicated more accuracy of the model prediction in comparison with the model of Dalirsefat and Feyzi.…”

Section: ■ Introductionmentioning

confidence: 99%

“…So, it could be concluded that using the PC-SAFT EOS could be suitable for wax precipitation models. 16 The previously mentioned models 14,15 indicated that the cubic EOS cannot calculate the precipitated wax amount as well as PC-SAFT EOS. Also, the SS model usually overestimates the WAT value without using adjustable parameters.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Meighani et al used the perturbed chain form of the statistical associating fluid theory (PC-SAFT), for predicting the amount of precipitated wax. The AAD of 0.3–0.8% was reported in this work . Bagherinia et al improved the wax precipitation approach using the PC-SAFT EOS for the calculation of the vapor and liquid phase’s fugacities and the UNIQUAC equation for evaluating the activity coefficient in the solid phase.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation and Thermodynamic Modeling of Wax Precipitation in Crude Oil Using the Multi-Solid Model and PC-SAFT EOS

Heidariyan

Ehsani

Behbahani³

et al. 2019

Energy Fuels

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Wax precipitation is a significant problem in the oil and gas industry as it may cause plugging of the process equipment and transportation pipelines during oil transportation, production, and refining. Therefore, an accurate thermodynamic model for prediction of the wax appearance temperature (WAT) at especially high pressures can be helpful to deal with this problem. In this work, first, the WAT values for nine types of Iranian live crude oils were measured using a PVT cell equipped with a solids detection system (SDS). Then, an improved thermodynamic model based on the multi-solid (MS) model of wax precipitation, which was coupled with the chain form of the statistical associating fluid theory (PC-SAFT) equation of state (EOS), was developed to correlate the measured experimental data. Also, the MS model of wax precipitation was coupled with the Peng–Robinson (PR) EOS to be compared with the proposed model. Solid–liquid equilibria (SLE) were employed for the pressures above the bubble curve, and vapor–liquid–solid equilibria (VLSE) were utilized below the bubble curve in the P-T diagram. In the proposed model, the crude oil was considered as a mixture of the paraffinic, naphthenic, and aromatic fractions, and the plus fraction has been characterized using the three-parameter gamma probability function theory, to improve the characterization of the previous models based on two-parameter gamma probability function theory. The results of the experiments indicated that the WAT values decreased by increasing the pressure at the lower range of pressures. Also, the correlated values show that the proposed model based on PC-SAFT EOS with the correlated parameters can predict the WAT values better than the MS model with PR EOS with the %AAD below %1 at a wide range of pressures.

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“…The knowledge of wax formation phenomena has been improved both experimentally and theoretically . While literature is rich in reporting wax appearance temperature (WAT), scientists argue that wax disappearance temperature (WDT) is closer to the wax equilibrium condition .…”

Section: Introductionmentioning

confidence: 99%

Phase boundaries for synthetic light oils and gas condensate mixtures using predictive equations of state with a solid solution model

Nasrifar

Javanmardi

2018

Can J Chem Eng

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Phase boundaries for five synthetic paraffinic mixtures were predicted using a previously developed Gibbs energy minimization algorithm. In this method, the vapour and liquid phases were described by cubic equations of state (EoS). These EoS employed a predictive temperature-dependent group-contribution binary interaction parameter model. The solid phase was described using a universal quasi-chemical activity coefficient (UNIQUAC) solid solution model. Using this algorithm, the phase boundaries were calculated from a temperature-search strategy. The predicted phase boundaries were found to be in good agreement with experimental phase boundaries for vapour-liquid (VL), solid-liquid (SL), solid-vapour (SV), and solid-vapour-liquid (SVL) regions. The model was also used to predict the phase boundaries at low temperatures where no experimental data were available.

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A modified thermodynamic modeling of wax precipitation in crude oil based on PC-SAFT model

Cited by 14 publications

References 30 publications

Experimental Measurements of Wax Precipitation Using a Modified Method of Simultaneous Centrifugation and High-Temperature Gas Chromatography

Experimental Measurements of Wax Precipitation Using a Modified Method of Simultaneous Centrifugation and High-Temperature Gas Chromatography

Experimental Investigation and Thermodynamic Modeling of Wax Precipitation in Crude Oil Using the Multi-Solid Model and PC-SAFT EOS

Phase boundaries for synthetic light oils and gas condensate mixtures using predictive equations of state with a solid solution model

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