An Investigation of Two-Phase Oil/Water Paraffin Deposition

Couto, Guilherme H.; Chen, Hong; Delle-Case, Emmanuel; Sarica, Cem; Volk, M.

doi:10.2118/114735-pa

Cited by 29 publications

(24 citation statements)

References 3 publications

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“…Using a cold finger apparatus, a few studies have reported that increasing the water-cut in a two-phase oil−water deposition process resulted in a decrease in the amount of solids deposition. 23,24,26,27 The same trend was also reported by Bruno et al, 25 who used a flow-loop experimental setup. Couto et al 24 observed no difference in the amount of wax deposited when salt water was used instead of fresh water.…”

Section: ■ Introductionsupporting

confidence: 57%

“…23,24,26,27 The same trend was also reported by Bruno et al, 25 who used a flow-loop experimental setup. Couto et al 24 observed no difference in the amount of wax deposited when salt water was used instead of fresh water. Kasumu and Mehrotra 22 did not observe a relationship between the water content and the mass of wax deposited in a flow-loop apparatus; i.e., there was no consistent effect of water on the deposit mass.…”

Section: ■ Introductionsupporting

confidence: 57%

“…22−31 The role of water in the wax deposition process is not well established, possibly due to the complexity caused by the aqueous phase and the difficulty in obtaining consistent results with water-in-oil mixtures. 24 Li et al 28 reported that the presence of water decreased the amount of wax deposited, especially on a water-wet surface. Using a cold finger apparatus, a few studies have reported that increasing the water-cut in a two-phase oil−water deposition process resulted in a decrease in the amount of solids deposition.…”

Section: ■ Introductionmentioning

confidence: 99%

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Solids Deposition from Wax–Solvent–Water “Waxy” Mixtures Using a Cold Finger Apparatus

Kasumu

Mehrotra

2015

Energy Fuels

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The solids deposition from one-phase and two-phase waxy mixtures (comprising a multicomponent paraffinic wax dissolved in a multicomponent solvent, and water) was studied using a cold finger experimental apparatus. The deposition experiments were performed with a 10 mass % wax solution, containing 0, 10, 20, and 30 vol % water, with two different rates of agitation, and for nine different deposition times ranging from 30 s to 24 h. The water content of the deposit was found to be not related to the water content of the waxy mixture. The short-duration experiments showed the deposition process to be very fast, with more than half of the deposition process completed in 30 s. Following a rapid rate of deposition initially, the deposit mass was observed to increase slowly to reach steady state at about 12 h. The deposit mass decreased with an increase in the agitation speed. The deposition data were modeled satisfactorily with a steady-state heat-transfer model and an unsteady-state model based on the moving boundary problem formulation. The results confirmed the liquid−deposit interface temperature to be equal to the wax appearance temperature (WAT) of the wax solution throughout the deposition process, i.e., for all deposition times. The results of this study provide further confirmation that the solids deposition process can be described adequately with an approach based solely on heat-transfer considerations. ■ INTRODUCTIONThe precipitation and deposition of solids are of significant importance in the production, transportation, and processing of "waxy" or paraffinic crude oils because wax deposition can damage oil reservoir formations and wells and cause blockage of pipelines and process equipment. Solids deposition in pipelines and process equipment causes an increase in pressure drop, an increase in pumping power requirement, and/or a decrease in efficiency. Challenges associated with solids deposition are more severe in cold environments, especially in subsea conditions, where seabed temperatures can be as low as 4°C. 1 With increasing prevalence of deep-water−oil recovery, 2 crude oil is transported over longer distances with an increase in exposure to low temperatures. Such solids deposition problems are expected to become worse and so will the control and remediation costs associated with them.Waxes are mixtures of long-chain hydrocarbons with carbon numbers ranging from 18 to 65. 3 Waxes occur in significant proportions in paraffinic crude oils. These waxes are less soluble in the crude oil at lower temperatures and tend to crystallize and deposit on cooler surfaces. The temperature at which the first wax crystals start to appear in the crude oil during cooling is known to as the wax appearance temperature (WAT) or the cloud point temperature (CPT). It is pointed out that the wax disappearance temperature (WDT, measured while heating a sample) has been shown to provide a better representation of the true solid−liquid phase transformation temperature or the liquidus temperature. 4 Although somewhat higher ...

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Section: ■ Introductionsupporting

confidence: 57%

Section: ■ Introductionsupporting

confidence: 57%

Section: ■ Introductionmentioning

confidence: 99%

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Solids Deposition from Wax–Solvent–Water “Waxy” Mixtures Using a Cold Finger Apparatus

Kasumu

Mehrotra

2015

Energy Fuels

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“…28−32 A literature review showed that the wax deposition process is not well-established for two-phase oil−water flow conditions, perhaps due to the increased complexity caused by the addition of the water phase and the difficulty in obtaining consistent results with oil−water mixtures. 29 The presence of water has been reported to decrease the amount of wax deposited, especially on a water-wet surface. 33 Using a cold-finger experimental apparatus, a few studies have reported a decrease in the amount of solids deposition with increasing water cut for a two-phase oil−water deposition process.…”

Section: ■ Introductionmentioning

confidence: 99%

Solids Deposition from Two-Phase Wax–Solvent–Water “Waxy” Mixtures under Turbulent Flow

Kasumu

Mehrotra

2013

Energy Fuels

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The deposition of solids from two-phase waxy mixtures (comprising a multicomponent paraffinic wax dissolved in a multicomponent solvent and water) was studied under turbulent flow conditions in a flow-loop apparatus, incorporating a cocurrent double-pipe heat exchanger. The deposition experiments were performed with 6 mass % wax solutions, containing 0, 5, 10, 15, 20, 25, and 30 vol % water, at different flow rates over 5600 < Re < 25 300, and at different hot and cold stream temperatures. In the bench-scale apparatus, the deposit was formed rapidly such that a thermal steady state was attained within 10−20 min in all experiments. The water content of the deposit was found to be not related to the water content of the waxy mixture. The deposit mass was found to decrease with an increase in Re, the waxy mixture temperature, and/or the coolant temperature. The deposit mass also increased as the water content of the waxy mixture was increased to about 10 vol % and decreased thereafter. The deposition data, analyzed with a steady-state heat-transfer model, indicated that the liquid−deposit interface temperature was close to the wax appearance temperature of the waxy mixture. The average thermal conductivity of the deposit was estimated to be 0.38 W m −1 K −1 . Overall, the results of this study confirm that the deposition process from waxy mixtures is primarily thermally driven.

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“…The TUWAX simulator has many versions and has been developed over time with contributions from different graduate work (Matzain, 1996;Lund, 1998;Matzain, 1999;Apte, 1999;Manabe, 2001;Heranandez-Perez, 2002;Couto, 2004;Rodriguez, 2006;Singh, 2013). The…”

Section: Molecular Diffusionmentioning

confidence: 99%

Fundamental Study of Wax Deposition Under Real Flow Conditions

Fleming¹

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An Investigation of Two-Phase Oil/Water Paraffin Deposition

Cited by 29 publications

References 3 publications

Solids Deposition from Wax–Solvent–Water “Waxy” Mixtures Using a Cold Finger Apparatus

Solids Deposition from Wax–Solvent–Water “Waxy” Mixtures Using a Cold Finger Apparatus

Solids Deposition from Two-Phase Wax–Solvent–Water “Waxy” Mixtures under Turbulent Flow

Fundamental Study of Wax Deposition Under Real Flow Conditions

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