Evaluation of pressure on the crystallization of waxes using microcalorimetry

Vieira, Lenise C.; Buchuid, Maria B.; Lucas, Elizabete F.

doi:10.1007/s10973-012-2252-3

Cited by 13 publications

(8 citation statements)

References 23 publications

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“…So, the use of calorimetric or microcalorimetric methods to determine enthalpy, entropy or free energy can be insightful to infer the nature and magnitude of forces associated with the phenomenon(a) under investigation. [28][29][30][31][32] Different volumes of asphaltene-in-toluene solutions, resin-in-n-heptane solutions and also pure solvents were mixed in this experimental work. Although, it is indisputable that the changes in the solubility parameter affect the interaction between solutes from different solvents, our aim here was to force the asphaltenes (from the toluene solution) to come out of solution, by adding a bad solvent (resins containing n-heptane), thus generating large specific surface area of asphaltene particles (colloidal ones) with which resins (in n-heptane solution) could promptly interact.…”

Section: Isothermal Microcalorimetrymentioning

confidence: 99%

A study of asphaltene-resin interactions

Marques¹,

Pereira²,

Bueno³

et al. 2012

J. Braz. Chem. Soc.

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Foi realizado um estudo para investigar a interação entre asfaltenos (em soluções de tolueno) e resinas (em soluções de n-heptano). Para entender melhor o tipo de interação entre essas frações, quantificou-se o consumo de resina quando asfaltenos (dissolvidos em tolueno) foram precipitados com uma solução de n-heptano contendo resina. Os resultados indicaram que a precipitação de asfaltenos ocorre juntamente com a redução na concentração de resina. Os perfis das isotermas de ligação indicaram que a saturação ocorreu em um caso, em quanto que o efeito cooperativo com posterior platô inicial foi observado para duas outras amostras. Estes resultados confirmaram a hipótese de que resinas podem adsorver em asfaltenos, mas não podem evitar floculação e precipitação de asfaltenos. Além disso, resultados de microcalorimetria sugeriram que a resina e asfalteno interagem por forças fracas de van der Waals. Estes resultados estão em contraste com a escola de pensamento predominante desde a década de 1940 que advoga que as resinas podem peptizar e estabilizar asfaltenos.A study was carried out to investigate the interaction between asphaltenes (in toluene solutions) and resins (in n-heptane solutions). To better understand the type of interaction between these fractions, it was quantified the resin uptake when asphaltenes (dissolved in toluene) were precipitated by a resin-containing n-heptane solution. These results indicated the asphaltene precipitation occurs together with a reduction in the resin concentration. The binding isotherm profiles indicated that saturation occurred in one case, while collective association following an initial plateau was observed for the other two samples. These results confirmed the hypothesis that resins can adsorb on asphaltenes but cannot prevent asphaltenes from flocculating and precipitating. Furthermore, microcalorimetric results suggested that the resin and asphaltene interact by weak van der Waals forces. These results are in stark contrast with the school of thought prevalent since the 1940s that resins can peptize and stabilize asphaltenes.

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Section: Isothermal Microcalorimetrymentioning

confidence: 99%

A study of asphaltene-resin interactions

Marques¹,

Pereira²,

Bueno³

et al. 2012

J. Braz. Chem. Soc.

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“…Amphiphilic polymers have widespread applications. In the petroleum industry, they are used in drilling fluids and for demulsification of water‐in‐oil emulsions, inhibition of wax deposition, stabilization of asphaltenes in crude oil, flocculation of asphaltenes, inhibition of naphthenate deposition, enhanced oil recovery, and water treatment . In drilling, hydrophobically modified starches can be used to control filtrate from emulsified fluids .…”

Section: Introductionmentioning

confidence: 99%

“…For demulsification of emulsions, the great majority of demulsifier agents are based on surfactant copolymers of poly (propylene oxide)–poly(ethylene oxide) . Copolymers made from ethylene and vinyl acetate and acrylic copolymers with long hydrocarbon chains have long been used to inhibit deposition of paraffins from crude oil . Polymers containing cardanol and sulfonated polystyrene have been tested as stabilizers/flocculants of asphaltenes in petroleum .…”

Section: Introductionmentioning

confidence: 99%

Solubility behavior of amphiphilic sulfonated copolymers based on styrene–stearyl methacrylate and styrene–stearyl cinnamate

Palermo

Souza

Silvino

et al. 2015

J of Applied Polymer Sci

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Amphiphilic polymers have found many applications, so many types of these copolymers have been prepared. Specifically, sulfonated polystyrene acts, for example, as a flocullant or dispersant of petroleum asphaltenes as a function of its hydrophilic-hydrophobic balance. However, when changing the sulfonation degree, looking for the best performance, the solubility also changes, and sometimes it is responsible for making the polymer unsuitable for any application. Therefor, this work investigates in detail the changes in the solubility range of copolymers based on styrene-stearyl methacrylate and styrene-stearyl cinnamate with different molar compositions and different sulfonation degrees. The copolymers were synthesized and characterized by 1 H-NMR, Fourier transform infrared spectroscopy, and elemental analysis. In the range of compositions analyzed, with increasing content of long hydrocarbon chains, not only the displacement of the solubility in solvents with lower solubility parameter (d), but also the broadening of the solubility range was observed. In general, the solubility was directly related to the sulfonic group content, but there appeared to be an influence of the randomness of the sulfonation reactions along the chains. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43112.

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“…Therefore, heavy oil with high viscosity, such as Belayium crude oil, cannot easily diffuse from the surface of the samples into the internal space of the network. However, toluene is the solvent most frequently used to dissolve asphaltene in crude oil, while other factors such as the presence of dissolved gases affect the solubility of petroleum and of fractions made from it . Thus, we have used crude oil diluted with toluene so that the swelling behavior of the samples could be easily evaluated.…”

Section: Resultsmentioning

confidence: 99%

Porous crosslinked copolymers of octadecyl acrylate with acrylic acid as sorbers for crude petroleum spills

Atta

Brostow

Lobland

et al. 2013

Polymer International

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Bulk and suspension polymerization were used to prepare octadecyl acrylate/acrylic acid (ODA/AA) copolymers. AA content ranged from 0 to 90 mol%. Divinyl benzene was used as a crosslinker at several concentrations (1, 4 and 10 wt%). Isopropyl alcohol or dioctyl phthalate and methyl benzoate were used as the reaction solvents in the presence of poly(vinyl alcohol) as a dispersing agent and 2,2-azobis isobutyronitrile as the initiator. The polymers so prepared were coated onto poly(ethylene terephthalate) nonwoven (NWPET) fibers. The effects of copolymerization, feed composition, crosslinker concentration and reaction medium or solvent on morphology including porosity and the dynamic mechanical and swelling properties of the crosslinked polymers were determined. Swelling tests were performed in toluene and in 10% crude petroleum diluted with toluene. Bulk polymerization does not result in the formation of a continuous liquid absorbing material while suspension polymerization enables sorbers to be obtained with desired properties. Coating ODA/AA copolymers onto NWPET increases liquid absorption.

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Evaluation of pressure on the crystallization of waxes using microcalorimetry

Cited by 13 publications

References 23 publications

A study of asphaltene-resin interactions

A study of asphaltene-resin interactions

Solubility behavior of amphiphilic sulfonated copolymers based on styrene–stearyl methacrylate and styrene–stearyl cinnamate

Porous crosslinked copolymers of octadecyl acrylate with acrylic acid as sorbers for crude petroleum spills

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