Influences of different functional groups on the performance of polyoctadecyl acrylate pour point depressant

Yang, Fei; Xiao, Zuoqu; Yao, Bo; Li, Chuanxian; Wang, Lu; Shi, Xin; Sun, Guangyu; Yan, Kongyao

doi:10.1080/10916466.2016.1212211

Cited by 27 publications

(9 citation statements)

References 10 publications

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“…According to the position of the long alkyl chains in the molecular structure, polymeric PPDs could be classified into two types: linear copolymers with long alkyl chains located in the backbone [such as the ethylene–vinyl acetate copolymer (EVA) − ] and comblike copolymers with long alkyl chains located in the side chain (such as the polyacrylates − ). To guide the application of polymeric PPDs in crude oil pipelines, the effects of the molecular structure of PPDs, − wax composition and content, , and thermal/shear histories , on the efficiency of the polymeric PPDs have been widely studied; the mechanisms of polymeric PPDs were also well-discovered: − the polymeric PPDs could participate in the precipitation process of wax molecules and then change the morphology of precipitated wax crystals, thus improving the flow behavior of waxy crude oil.…”

Section: Introductionmentioning

confidence: 99%

Ethylene–Vinyl Acetate Copolymer and Resin-Stabilized Asphaltenes Synergistically Improve the Flow Behavior of Model Waxy Oils. 1. Effect of Wax Content and the Synergistic Mechanism

Yao

Zhang

et al. 2018

Energy Fuels

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Both polymeric pour point depressants (PPDs) and asphaltenes can improve the flowability of waxy oils. However, the effect of polymeric PPDs together with asphaltenes on the flowability of waxy oils is not clear. In this paper, the synergistic effect of ethylene–vinyl acetate (EVA) PPD (100 ppm) and resin-stabilized asphaltenes (0.75 wt %) on the flow behavior of model waxy oils (10–20 wt % wax content) was investigated through rheological tests, DSC analysis, microscopic observation, and asphaltenes precipitation tests. The results showed that the asphaltenes disperse well in the xylene/mineral oil solvent as small aggregates (around 550 nm) with the aid of resins. The EVA or asphaltenes alone moderately improve the flow behavior of waxy oils by changing the wax crystals’ morphology from long and needlelike to a large, radial pattern or fine particles, respectively. The wax precipitation temperatures (WPTs) of waxy oils are also slightly decreased by adding EVA or asphaltenes, meaning that the cocrystallization effect between the additives and waxes is dominant. The addition of EVA together with asphaltenes cannot further decrease the WPT, but it can dramatically decrease the pour point, gelation point, G′, G″, and apparent viscosity of waxy oils, indicating that a synergistic effect exists between EVA and asphaltenes. The synergistic effect deteriorates upon increasing the wax content of waxy oils. The EVA molecules can adsorb on the surface of asphaltene aggregates, thus inhibiting the asphaltenes precipitation and forming the EVA/asphaltenes composite particles. The formed composite particles can act as wax-crystallizing templates and then greatly change the wax crystals’ morphology into large, compact, and spherelike wax crystal flocs, thus dramatically improving the waxy oil flow behavior. This work enriches the theory of micro/nano composite PPDs, which is helpful for developing new PPDs with high efficiency.

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Section: Introductionmentioning

confidence: 99%

Ethylene–Vinyl Acetate Copolymer and Resin-Stabilized Asphaltenes Synergistically Improve the Flow Behavior of Model Waxy Oils. 1. Effect of Wax Content and the Synergistic Mechanism

Yao

Zhang

et al. 2018

Energy Fuels

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“…Four characteristics of side chains/pendants that influence the efficacy of additives were identified, namely, functional group (Zhao et al and Wu et al), pendant length (Li et al and Deshmukh and Bharambhe , ), monomer ratio (Jiang et al, Fu et al., Yang et al), and graft density (Jiang et al). While analyzing the effects of functionality of side chains, Zhao et al studied the effect of replacing the alkyl side chain linked to the amide group in a maleic anhydride-based copolymer, with a benzene ring and a benzimidazole ring (as shown in Figure ).…”

Section: Classification Of Flow Improversmentioning

confidence: 99%

“…Some authors have modified the monomer ratio and have observed the efficacies of the different polymeric additives. − Jiang et al modified the alkyl amide content (octadecyl chain, nonpolar; amide, polar) in maleic anhydride-based polymers. They synthesized polymers with different amidation ratios ( f ), which indicates the number of alkyl amides resulting from maleic anhydride groups.…”

Section: Classification Of Flow Improversmentioning

confidence: 99%

“…With a further increase in styrene content (beyond 2:3 ratio of octadecyl acrylate and styrene; feed ratio = 0.6 octadecyl acrylate content), octadecyl acrylate content decreases (that can cocrystallize with paraffins), and hence, PPD performance degrades. Yang et al 76 studied the effect of introducing different functional groups in acrylate-based polymers on the apparent viscosity, yield stress, and wax morphology of Changqing waxy crude oil. They varied the monomer ratio for polyoctadecyl acrylate−vinyl acetate (POA-VA), polyoctadecyl acrylate−maleic anhydride (POA-MA), and polyoctadecyl acrylate−styrene (POA-St) in different feed ratios.…”

Section: Classification Of Flow Improversmentioning

confidence: 99%

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Chemical Additives as Flow Improvers for Waxy Crude Oil and Model Oil: A Critical Review Analyzing Structure–Efficacy Relationships

et al. 2022

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Waxy crude oil has become a crucial unconventional oil alternative owing to the depleting conventional oil resources. However, ascertaining flow assurance in a waxy crude oil pipeline at low temperatures is challenging due to the high viscosity and gelation properties of waxy crude oil and wax deposition on the pipeline wall. Researchers and industries use different classes of chemical additives to resolve the flow assurance issues. The current review aims to build a relationship between the structural properties of chemical additives and their flow improvement efficacy. A wide array of compounds reported in the past decade has been critically examined to understand the progress in the field. Polymers form a bulk of these compounds. However, there is a shift toward polymer nanocomposites owing to their better effect compared to pure polymers. Surfactants, organic solvents, and other molecules have also been utilized as additives to ensure flow during waxy crude oil transportation. The presence of different structural properties such as alkyl chain length, aromatic rings, size of aromatic rings, polar groups, and others have been related to their effect on the flowability of waxy crude oil. Moreover, the factors related to scaling of lab-scale results to industry level have been enumerated. The future directions and perspectives related to utilizing structure–efficacy relationships of chemical additives have been discussed. In contrast to the existing literature, special importance has been given to the chemical structures of additives and their molecular interactions with waxy oils. The perspective of the structure–efficacy relationship will help in designing novel additives with greater efficacy and suitability for waxy crude oil.

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“…In the petroleum industry, treating the crude oil with small amounts of polymeric pour point depressants (PPDs) is a common way to improve its flowability . During the last 3 decades, people have developed many types of polymeric PPDs, among which the linear copolymer PPDs, such as ethylene–vinyl acetate copolymer (EVA), − and the comb-like copolymer − PPDs, such as polyoctadecyl acrylate (POA), have been widely used in the exploitation and pipeline transportation of waxy crude oil. These two types of polymeric PPDs are composed of both the nonpolar alkane chains and the polar groups, with the nonpolar parts affecting the crystallization process of paraffin waxes and the polar groups interfering in the growth of wax crystals .…”

Section: Introductionmentioning

confidence: 99%

Ethylene–Vinyl Acetate Copolymer and Resin-Stabilized Asphaltenes Synergistically Improve the Flow Behavior of Model Waxy Oils. 2. Effect of Asphaltene Content

Yao

Yang

et al. 2018

Energy Fuels

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In part 1 (10.1021/acs.energyfuels.7b03657), the synergistic effect of ethylene–vinyl acetate copolymer (EVA) pour point depressant (PPD) and rensin-stabilized asphaltenes on improving the flowability of synthetic waxy oil has been verified. This paper is a continuous work studying the effect of the asphaltene content (0.01–3 wt %) on the synergistic effect between EVA PPD and resin-stabilized asphaltenes. The results showed that, in the absence of EVA and with the increase of the asphaltene content, the precipitated wax crystals of the waxy oil tend to grow gradually from initial big needle-like to smaller and more regular (spherical-like) particles with a larger amount; therefore, adding aphaltenes can only decrease the apparent viscosity of waxy oil at the temperature range slightly lower than the wax precipitation temperature (WPT) (the precipitated wax crystal amount is low), and the temperature range is broadened by increasing the asphaltene content. When the temperature is decreased far below the WPT of the oil, however, the apparent viscosity of oil rises up with increasing the aphaltene content as a result of the large amount of wax crystals and asphaltenes. In addition, only a part of the asphaltenes participates in the wax precipitation process, and the rest of the asphaltenes disperses in the oil phase as asphaltene aggregates, which could adhere or adsorb on the existing wax crystal flocs, strengthening the interactions between wax flocs. After asphaltenes are added together with EVA, EVA molecules can adsorb onto the asphaltene aggregates to generate the formation of the EVA/asphaltene composite particles, and the synergistic effect of the EVA/asphaltene composite particles on the flowability of waxy oil improves first with the increase of the asphaltene content and then somewhat deteriorates at a higher asphaltene content (3 wt %). When the asphaltene content is low, the wax crystal modification by the composite particles is insufficient and the formed large wax flocs have a very loose structure, which favor the wax crystal structure building. When the asphaltene content is too high (3 wt %), EVA/asphaltene composite particles disperse the precipitated wax flocs into relatively small spherical-like wax flocs with a larger amount. Although the structure of the wax flocs is compact, the large amounts of wax flocs and asphaltene aggregates in the oil phase lead to somewhat deterioration of the synergistic performance of EVA and asphaltenes. At the middle contents of asphaltenes (0.75–1.5 wt %), EVA/asphaltene composite particles cause the formation of relatively large spherical-like wax flocs with a compact structure and the asphaltene content is moderate, both of which greatly promote the flow behavior improvement of the oil.

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Influences of different functional groups on the performance of polyoctadecyl acrylate pour point depressant

Cited by 27 publications

References 10 publications

Ethylene–Vinyl Acetate Copolymer and Resin-Stabilized Asphaltenes Synergistically Improve the Flow Behavior of Model Waxy Oils. 1. Effect of Wax Content and the Synergistic Mechanism

Ethylene–Vinyl Acetate Copolymer and Resin-Stabilized Asphaltenes Synergistically Improve the Flow Behavior of Model Waxy Oils. 1. Effect of Wax Content and the Synergistic Mechanism

Chemical Additives as Flow Improvers for Waxy Crude Oil and Model Oil: A Critical Review Analyzing Structure–Efficacy Relationships

Ethylene–Vinyl Acetate Copolymer and Resin-Stabilized Asphaltenes Synergistically Improve the Flow Behavior of Model Waxy Oils. 2. Effect of Asphaltene Content

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