Crystal Behavior of Paraffin Wax.

Ferris, S. W.; Cowles, H. C.

doi:10.1021/ie50431a016

Cited by 32 publications

(17 citation statements)

References 3 publications

(3 reference statements)

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“…1A). These crystallites increase the viscosity of crude oil (12), causing droplets to coalesce, and become multiphase emulsions ( Fig. 1B) (13,14).…”

Section: Introductionmentioning

confidence: 99%

Wax-wetting sponges for oil droplets recovery from frigid waters

et al. 2021

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Energy-efficient recovery of oil droplets from ice-cold water, such as oil sands tailings, marine, and arctic oil spills, is challenging. In particular, due to paraffin wax crystallization at low temperatures, the crude oil exhibits high viscosity, making it difficult to collect using simple solutions like sponges. Here, we report a wax-wetting sponge designed by conforming to the thermoresponsive microstructure of crude oil droplets. To address paraffin wax crystallization, we designed the sponge by coating a polyester polyurethane substrate with nanosilicon functionalized with paraffin-like octadecyl ligands. The wax-wetting sponge can adsorb oil droplets from wastewater between 5° and 40°C with 90 to 99% removal efficacy for 10 cycles. Also, upon rinsing with heptol, the adsorbed oil is released within seconds. The proposed approach of sponges designed to conform with the temperature-dependent microstructure of the crude oils could enable cold water technologies and improve circular economy metrics in the oil industry.

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“…1A). These crystallites increase the viscosity of crude oil (12), causing droplets to coalesce, and become multiphase emulsions ( Fig. 1B) (13,14).…”

Section: Introductionmentioning

confidence: 99%

Wax-wetting sponges for oil droplets recovery from frigid waters

et al. 2021

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“…Macro-crystalline paraffin wax crystallizes into platelet-like structures, as illustrated in Figure 1(b). 12 Below the gelation temperature, linear alkane components tend to form a volume-spanning network of plate-like crystals, entraining the liquid oil phase and forming a colloidal or physical gel, as illustrated in Figure 1(c). Affinity between wax crystals arises due to London van der Waals dispersion forces, conferring upon the wax structure a distinct mechanical strength.…”

Section: Introductionmentioning

confidence: 99%

Influence of Measuring Geometry on Rheomalaxis of Macrocrystalline Wax–Oil Gels: Alteration of Breakage Mechanism from Adhesive to Cohesive

et al. 2019

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Rheological measurement of wax-oil gel breakage is highly susceptible to the phenomenon of adhesive breakage, hindering instrument-scale replication of cohesive breakage processes. Adhesive breakage measurements are notoriously irreproducible, due to strongly non-affine gel deformation. Efforts to ensure mechanical fixation give rise to spatially inhomogeneous deformation fields in the measuring geometry, particularly with respect to azimuthal and radial location. In order to elucidate the functional role of mechanically fixating geometries during gel breakage processes, 3 model solutions were prepared containing 5 wt%, 7.5 wt%, and 10 wt% macro-crystalline wax in dodecane. Rheograms were acquired in controlled deformation mode at imposed shear rates in the range of 0.1-1.0 s −1 using a vane or a cone and plate geometry. Yield stress values, nominally ascribed to primary peak height, were established based on 95% confidence intervals. Yielding trends confirm that adhesive breakage is particularly pronounced in high solid-fraction gels. A solid-fraction threshold delineates cohesive breakage in low solidfraction gels from inherent adhesive breakage in high solid-fraction gels. Mechanical fixation in a vane geometry precludes wall slippage, ensuring cohesive breakage; resultant yield stress values follow a modified power-law dependency on total wax content, characterized by a power law exponent of ∼1.25. Nonuniform deformation within the vane geometry confers a modest (artificial) reduction in apparent yield stress value as a consequence of azimuthal integration of the torque signal. Nonuniform deformation also confers a distinct (artificial) broadening of the breakage peak, and is accompanied by the appearance of a new shoulder-peak located at a deformation value of ∼5. Conversely, in the cone and plate geometry, adhesive breakage occurs inherently for high solid-fraction gels, and is manifested by a substantial reduction in measured yield stress, albeit without a concomitant peak broadening. Hence, the practical utility of the cone and plate geometry is limited to low solid-fraction gels that inherently exhibit cohesive breakage behavior. Mechanical fixation afforded by the vane geometry effectively precludes wall slippage, enhancing measurement reproducibility while simultaneously ensuring cohesive breakage of high solid-fraction wax-gels that otherwise rupture in adhesive mode.

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“…Equation 12 can be transformed in completely macroscopic terms by multiplying both m and k by Avogadro's number N A to get the molecular weight MW of the particles and the universal gas constant R:…”

Section: B Sedimentation Equilibriummentioning

confidence: 99%

Quantification of Asphaltene and Wax Sludge Build-up in Crude Oil Storage Facilities

Leontaritis¹

2005

All Days

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractAt some thermodynamic conditions, asphaltenes flocculate into larger, almost spherical particles that have a specific gravity of 1.05 to 1.10. Work is cited here that indicates that asphaltene stable colloids exist in oil as very minute particles and that their pre-flocculation sizes are in the range of about 10 to 15 Å. This corresponds to 334 and 1,128 molecular weight respectively, assuming asphaltene spherical colloids and an experimentally determined asphaltene density of 1.06 g/cm 3 . The reason for this high specific gravity of asphaltene particles compared to the rest of the molecules of oils is that they consist mostly of asphaltenes and resins, the heaviest constituents of oils. Roughly, resins have specific gravities of 0.95 to 1.0 and asphaltenes 1.1 to 1.2. Because of their high specific gravity asphaltene particles settle by the force of gravity in storage systems where the convection currents and shear forces are minimal. Some of these particles are large enough to overcome the convection currents and shear forces and settle in large separators and occasionally in large pipes due to Stoke's law effects, especially at elbows changing the direction of flow where the particles impinge against the pipe wall and are temporarily halted. This paper presents a modeling methodology for the simulation of sedimentation of asphaltene and wax particles in both onshore and offshore storage systems. The asphaltene and wax particle size distribution is usually available from microscopic observations, filtration, and thermodynamic models. The sedimentation calculation is done by assuming that the particles have settled and are at gravimetric equilibrium. Two examples are presented: one 1,000,000barrel FPSO case and one 250,000-barrel oil storage tank case. Both the FPSO and the tank had lost a substantial fraction of their capacity due to accumulation of asphaltene and wax sludge.

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Crystal Behavior of Paraffin Wax.

Cited by 32 publications

References 3 publications

Wax-wetting sponges for oil droplets recovery from frigid waters

Wax-wetting sponges for oil droplets recovery from frigid waters

Influence of Measuring Geometry on Rheomalaxis of Macrocrystalline Wax–Oil Gels: Alteration of Breakage Mechanism from Adhesive to Cohesive

Quantification of Asphaltene and Wax Sludge Build-up in Crude Oil Storage Facilities

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