ENERGY & FUELS
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2019
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IF 3.021
Hailin Yu,Zhengnan Sun,Guolin Jing,Zhiwei Zhen,Yang Liu,Kai Guo
Nanocomposite pour point depressants (PPDs) provide a new way to further improve the fluidity of waxy crude oil at low temperatures, which has important application values in pipeline transportation. In this work, the effect of ethylene-vinyl acetate (EVA) doped with magnetic spherical nanoparticles of Fe3O4 (30 nm) on the morphology of wax crystals and the flow behavior of Daqing crude oil was investigated by polarized optical microscopy and rheological testing. The results showed that, compared to the EVA PPD doped with spherical nano-SiO2 (with the same size), the EVA (VA = 28%)/Fe3O4 nanocomposite PPD caused Daqing crude oil to have a more compact and regular wax crystal structure and a weaker gel structure because of the synergistic effect of magnetic materials and heterogeneous nucleation. This study examines the mechanism of nanocomposite PPDs and provides a new perspective for the development of new nanohybrid PPDs.
研究领域:
石油工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Petroleum Science
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2024
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IF 6
Yi-Hai Yang,Li-Na Zhang,Zheng-Nan Sun,Ming-Xing Bai,Guo-Lin Jing,Yang Liu,Xiao-Yan Liu
Modified ethylene-vinyl acetate copolymer (EVAM) and amino-functionalized nano-silica (NSiO 2 ) particles were employed as the base materials for the synthesis of the nanocomposite pour point depressant designated as EVAM-g-NSiO 2 . This synthesis involved a chemical grafting process within a solution system, followed by a structural characterization. Moreover, combining macro-rheological performance with microscopic structure observation, the influence of the nanocomposite pour point depressant on the rheological properties of the model waxy oil system was investigated. The results indicate that when the mass ratio of NSiO 2 to EVAM is 1:100, the prepared EVAM-g-NSiO 2 nanocomposite pour point depressant exhibits excellent pour point reduction and viscosity reduction properties. Moreover, the nanocomposite pour point depressant obtained through a chemical grafting reaction demonstrates structural stability (the bonding between the polymer and nanoparticles is stable). The pour points of model waxy oils doped with 500 mg/kg ethylene-vinyl acetate copolymer (EVA), EVAM, and EVAM/SiO 2 were reduced from 34°C to 23, 20, and 21°C, respectively. After adding the same dosage of EVAM-g-NSiO 2 nanocomposite pour point depressant, the pour point of the model wax oil decreased to 12 °C and the viscosity at 32 °C decreased from 2399 to 2396.9 mPa·s, achieving an impressive viscosity reduction rate of 99.9%. Its performance surpassed that of EVA, EVAM, and EVAM/SiO 2 . The EVAM-g-NSiO 2 dispersed in the oil phase acts as the crystallization nucleus for wax crystals, resulting in a dense structure of wax crystals. The compact wax crystal blocks are difficult to overlap with each other, preventing the formation of a three-dimensional network structure, thereby improving the low-temperature flowability of the model waxy oil.
研究领域:
材料科学
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石油工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
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2024
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IF 5.5
Yihai Yang,Hanlin Chen,Zhengnan Sun,Mingxing Bai,Guolin Jing,Yang Liu,Xiaoyan Liu
Background Waxy crude oil is widely distributed worldwide and is an important fossil energy resource. Polyoctadecyl acrylate (POA) is a commonly used pour point depressant for waxy crude oil. Methods The introduction of polar groups is a novel and effective way to improve the performance of polymeric pour point depressants. Based on the solution radical polymerization reaction, this study successfully synthesized copolymer pour point depressants with different monomer ratios of poly(octadecyl acrylate-methylbutenol) (POAM) for the first time. Significant Findings The results indicate that among all the synthesized copolymer pour point depressants, the best performance is achieved when the molar ratio of octadecyl acrylate to methylbutenol is 3:1 (POAM-2). The addition of POAM-2 pour point depressant not only lowered the viscosity of the oil sample but also resulted in a decrease of 19 °C in the pour point, 7.3 °C in the gelation point, and the wax appearance temperature of the oil sample decreased by 4.1 °C. Microscopic images confirm that the POAM-2 changes the morphology of wax crystals from large plates to spherical shapes. The wax crystals also become denser, thereby inhibiting the formation of a network structure and further improving the rheological properties of the model waxy oil.
研究领域:
石油化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
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2019
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IF 3.021
Shuang Yang,Chuanxian Li,Fei Yang,Xiaoteng Li,Guangyu Sun,Bo Yao
For the pipeline transportation of waxy crude oil, pour point depressants (PPDs) have been developed and used to improve its flowability at low temperature. As supercritical CO2 (scCO2) flooding becomes a common technique to improve oilfield recovery, how the sensitivity of PPD changes due to the degassed crude oil treated by CO2 should be studied. In this work, the effect of scCO2 extraction on the performance of EVA in improving the flowability of Changqing degassed crude oil is investigated by means of a self-developed scCO2 treating equipment, SARA/HTGC analysis, SEM analysis, pour point test, rheological measurement, asphaltene precipitation test, particle size analysis, DSC test, and microscopic observation. The results show that without EVA addition, scCO2 extraction aggravates the flowability of the crude oil at low temperature. The scCO2 extraction extracts light components from asphaltene aggregates causing asphaltenes to precipitate, which inhibits the asphaltenes on playing a role as the natural PPD. As a result, it leads to the formation of smaller needle-like wax crystals with large amount, worsening the flowability of the crude oil. When the EVA is present, however, scCO2 extraction favors the functioning of EVA on improving the flowability of the crude oil at low temperature. The addition of EVA can slightly enhance the solubility of wax molecules thus decreasing the crude oil WAT to some extent, while can significantly change the morphology of precipitated wax crystals from small needle-like to agglomerated clusters, thus improving the flowability of the crude oil. Because of the synergistic effect of EVA and asphaltene aggregates after scCO2 extraction, a more compact EVA–asphaltene–wax ternary crystal structure will form thus further decreasing the pour point, elastic modulus, and equilibrium viscosity at low temperature.
研究领域:
石油工程
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化学工程
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
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2017
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IF 3.091
Guolin Jing,Zhengnan Sun,Ziyi Tu,Xudong Bian,Yu Liang
Nanohybrid pour-point depressants (PPDs) were prepared by organically modified nano-SiO2 in copolymers of ethylene and vinyl acetate (EVA) with various vinyl acetate contents. The effects of nanohybrid PPDs on the cold-flow properties of 25 wt % wax model oil were evaluated. The crystallization behavior and crystal morphology of the model oil at low temperatures were also observed using polarized optical microscopy. The results indicated that the co-crystallization and dispersion effects of EVA on wax crystals are the key factors in determining the heterogeneous nucleation effect of the nanohybrid PPDs. The vinyl acetate content in EVA strongly affects the compatibility between the modified nanosilica and EVA. As a result, the selection of an appropriate EVA according to the oils used and the compatibility factor is important. In this work, EVA (VA = 32%)/modified nano-SiO2 composite PPD [N-SiPPD(32)] provided the best cold-flow improvement for the model oil when doped at 500 ppm. The pour point of the model oil was reduced from 34 to 5 °C, which resulted in a regular, diamond-shaped, and uniform arrangement of wax morphologies.
研究领域:
材料科学
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石油工程
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
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2022
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IF 8.857
Xiaokang Zhang,Nana Li,Zhong Wei,Sheng Han,Bin Dai,Hualin Lin
The application of nanoparticles in terms of improving the cold flow properties of diesel fuels attracted more and more attention, and the composite technology of pour point depressant could further improve the cold flow properties of diesel fuels. A new type of nano-hybrid pour point depressant (PPD) was created in this study by copolymerising surface-modified carbon dots with tetradecyl methacrylate, which demonstrated good cold flow properties for diesel fuels (ΔSP = 21 °C, ΔCFPP = 9 °C). Besides, the ethylene-vinyl acetate (EVA) resin was also tested as a novel class of PPD to improve the cold flow properties of diesel fuels and exhibited excellent effect (ΔCFPP = 13 °C) on reducing the cold filter plugging point of diesel fuels. Thus, the combined technology of these two type of PPDs was used to further improve the cold flow properties of diesel fuels. The results indicated that the composite PPDs showed a great decrease in both solid point and cold filter plugging point of diesel fuels at a dose of 1500 ppm (ΔSP = 30 °C, ΔCFPP = 20 °C), which indicates better performance than achieved by either of them alone. In addition, polynomial and quadratic function fitting models are established to describe how the two main factors affect the cold flow properties of diesel fuels, and the fitting effects are well. In the end, using a differential scanning calorimeter , polarised optical microscope and rheological analysis, the paraffin crystallisation and morphology of wax crystals for diesel fuels before and after treatment with PPDs were studied, and the mechanism of heterogeneous nucleation and crystallisation of paraffin induced by PPD was proposed to explain the effects of nano-hybrid PPD, EVA resin and combined PPDs.
研究领域:
材料科学
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能源工程
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化学工程
✓ 已验证
DOI
高影响因子
ENERGY & FUELS
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2024
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IF 5.2
Lexin Zhang,Zhen Long,Yong He,Jinhang Wang,Xuebing Zhou,Lingli Shi,Deqing Liang
Wax deposition and hydrate formation are two unwelcome problems that can threaten the safety of pipeline transportation in the oil and gas industry. The existing prevention methods mainly aim at the flow blockage resulting from single solid phase, but rarely take into account multi-solid-phase systems, such as hydrate-wax, hydrate-sand, etc. Recently, it has been proposed that adding pour point depressants (PPDs) can not only improve the rheological property of waxy oil but also have potential to inhibit hydrate formation. In this study, a series of PPD polymethylsilsesquioxane (PMSQ) microspheres were synthesized by a two-step sol–gel method. First, the effect of PMSQ microspheres on wax deposition in waxy mineral oil was tested by differential scanning calorimetry (DSC). Then, the influence of PMSQ microspheres on the cyclopentane (CP) hydrate formation in waxy oil–water systems at the atmospheric pressure and temperature of −3 °C was investigated by using a self-assembly high-pressure reactor. The experimental results showed that the addition of PMSQ microspheres could reduce the wax appearance temperature (WAT) of waxy oil and prolong the nucleation time of the CP hydrate. Powder X-ray diffraction and laser confocal micro-Raman data indicated that the presence of PMSQ did not affect the sII crystal structure of the CP hydrates. A possible inhibition mechanism of PMSQ microspheres by the steric hindrance effect was proposed.
研究领域:
化学工程
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材料科学
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石油工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）