Jun Xu

Find an error

Name:

Organization: East China University of Science and Technology

Department:

Title:

Chemicals
References

Effect of Heteroaromatic Pendants in Comb Copolymers on Paraffin Crystallization and Cold Flow Ability of Crude Oil

Co-reporter:Hanqing Zhao, Jun Xu, Tao Li, Tongshuai Wang, Xiaoming Wei, Jie Wang, Yisheng Xu, Li Li, and Xuhong Guo

Energy & Fuels 2016 Volume 30(Issue 7) pp:5398

Publication Date(Web):June 8, 2016

DOI:10.1021/acs.energyfuels.6b00451

Adding comb copolymers as chemical additives is considered an effective and convenient method to improve the cold flow ability of crude oils. To improve the effectiveness of comb copolymers on the flow ability modification for crude oils with asphaltenes, poly(maleic acid amide-α-octadecene) with benzimidazolyl pendants (MACB) were designed and synthesized. In comparison to reported comb maleic anhydride copolymers (MAC) with octadecyl (MACO) or phenyl (MACP) pendants, MACB with heteroaromatic pendants are more efficient in reducing the yield stress of both model oil and Liaohe crude oil, as revealed by rheological measurements, in modifying the morphology of wax crystals, as observed by polarizing light microscopy (PLM), in lowering the wax appearance temperature (WAT) and quantity of wax precipitation, as determined by differential scanning calorimetry (DSC), and in decreasing the crystallinity of paraffins, as measured by X-ray diffraction (XRD). The benzimidazolyl pendants in MACB can provide both hydrogen bonding by amino groups and π–π stacking by benzyl groups with asphaltenes in crude oil, which improves the interactions with asphaltens and, thus, the effectiveness in modification the cold flow ability of crude oils.

Synthesis of Triblock Copolymers via RAFT Polymerization and Their Application as Surfactants for Crude Oil-in-Water Emulsion

Co-reporter:Jing Huang, Jun Xu, Kaimin Chen, Tongshuai Wang, Chao Cui, Xiaoming Wei, Rui Zhang, Li Li, and Xuhong Guo

Industrial & Engineering Chemistry Research 2015 Volume 54(Issue 5) pp:1564

Publication Date(Web):January 16, 2015

DOI:10.1021/ie504207r

As surfactants for crude oil emulsions, poly[N,N-(dimethylamino) ethyl methacrylate-b-poly(ethylene glycol) methyl ether methacrylate-b-lauryl methacrylate] (PDMA-b-PPMA-b-PLMA) triblock copolymers were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization and characterized by gel permeation chromatography and proton nuclear magnetic resonance spectroscopy. The copolymers exhibited high interfacial activity which could be tuned by simply adjusting the solution pH, and remarkably reduced the dodecane/water interfacial tension from 52.8 to 2.1 mN/m, producing stable dodecane-in-water emulsions even at a low concentration of 0.5 mg·mL–1. Utilization of these copolymers in Shengli crude oil further confirmed their emulsification capacity. The apparent viscosity of crude oil reduced from 34 000 to 350 mPa·s after emulsification at 20 °C, and the formed emulsions exhibited long-term stability for above 3 months. Due to the balanced hydrophilicity and hydrophobicity, PDMA22-PPMA27-PLMA36 proved to be the most efficient surfactant, which generated stable O/W emulsion with the smallest dosage.

Effect of Comb-type Copolymers with Various Pendants on Flow Ability of Heavy Crude Oil

Co-reporter:Jun Xu, Hejian Jiang, Tao Li, Xiaoming Wei, Tongshuai Wang, Jing Huang, Weina Wang, Anthony L. Smith, Jie Wang, Rui Zhang, Yisheng Xu, Li Li, Robert K. Prud’homme, and Xuhong Guo

Industrial & Engineering Chemistry Research 2015 Volume 54(Issue 19) pp:5204-5212

Publication Date(Web):April 23, 2015

DOI:10.1021/acs.iecr.5b00674

Modification of the paraffin crystallization and flow ability of waxy crude oil is of vital importance during transportation and restart processes at low temperature. To investigate the influence of pendants in comb-type copolymers on the cold flow ability of crude oil, maleic anhydride-α-octadecene copolymer and its derivatives with octadecyl (MAC), phenyl (AMAC), or naphthalene (NMAC) pendants were synthesized. These derivatives, when added to waxy crude oil, change the size and quantity of the paraffin crystals observed by polarizing light microscopy (PLM), improve the flow ability of waxy oils by reducing the viscosity and yield stress revealed by rheometer, and decrease the paraffin crystallization temperature and quantity of wax precipitation determined by differential scanning calorimetry (DSC). AMAC had the greatest effect followed by MAC and NMAC, respectively. It seems that small aromatic pendants improve the flow ability of waxy oils by adsorbing on the surface of asphaltenes, while large aromatic pendants impair the assembly of copolymers with asphaltenes by a higher steric hindrance.

Synthesis of comb-type copolymers with various pendants and their effect on the complex rheological behaviors of waxy oils

Co-reporter:Tongshuai Wang;Minglei Wang;Xiaoming Wei;Muxian Shen;Jing Huang;Rui Zhang;Li Li;Xuhong Guo

Journal of Applied Polymer Science 2015 Volume 132( Issue 11) pp:

Publication Date(Web):

DOI:10.1002/app.41660

ABSTRACT

To improve the flowability of waxy crude oil containing a high concentration of asphaltenes (AS), novel comb-type copolymers of poly(maleic acid polyethylene glycol ester-co-α-octadecene) (PMAC) and poly(maleic acid aniline amide-co-α-octadecene) (AMAC) with various grafting ratios (R_g) of PEG/aniline to maleic anhydride are synthesized. Model oils containing wax mixtures and AS are prepared to explore the effect of asphaltene concentration and the copolymers on the yield stress. The influence of the copolymers on the wax appearance temperature (WAT) of Liaohe high waxy oil is examined by rheological and microscopic methods. Experimental flow curves of shear stress as a function of shear rate are fitted following the Casson model to interpret the rheological properties of gelled waxy crude oil in the presence of AMACs, PMACs, and MAC. Compared with MAC, PMACs, and AMACs are more efficient in reducing the yield stress of both model oil and crude oil, which indicates a better flowability. It is found that PMAC1.0 and AMAC1.0 with a medium R_g can balance the interaction of copolymers with waxes and AS and reduce the yield stress much more than others. Between them, AMAC1.0 that possesses aromatic pendants is better than PMAC1.0, which only has polar pendants. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41660.

Flow improvement of Liaohe extraheavy oil with comb-type copolymers

Co-reporter:Hejian Jiang;Xiaoming Wei;Tongshuai Wang;Weina Wang;Li Li;Xuhong Guo

Journal of Applied Polymer Science 2014 Volume 131( Issue 8) pp:

Publication Date(Web):

DOI:10.1002/app.40082

Abstract

Liaohe extraheavy oil is a kind of special crude oil with high paraffin and asphaltene contents and a pour point of up to 60°C. To improve its flowability, comb-type poly(maleic alkylamide-co-α-octadecene) copolymers (MACs) with various amidation ratios were synthesized and used. Model oils containing paraffin mixtures with the same average carbon number to Liaohe extraheavy oil with and without asphaltene were prepared to explore the effect of the MACs on paraffin crystallization and asphaltene dispersion, respectively. We found that MACs reduced the yield stress, changed the size and shape of the paraffin crystals, and obstructed the paraffin crystallization for both model oils and extraheavy Liaohe oils as observed by rheology, polarizing light microscopy, X-ray diffraction, and differential scanning calorimetry. The MACs seemed to be an ideal candidate for improving the flowability of Liaohe extraheavy oils. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40082.

Effects of Amphiphilic Copolymer Dispersants on Rheology and Stability of Coal Water Slurry

Co-reporter:Jing Huang, Jun Xu, Dong Wang, Li Li, and Xuhong Guo

Industrial & Engineering Chemistry Research 2013 Volume 52(Issue 25) pp:8427

Publication Date(Web):June 5, 2013

DOI:10.1021/ie400681f

As dispersants of coal water slurry (CWS), two kinds of amphiphilic copolymers were synthesized by grafting of poly(styrene-co-maleic anhydride) with 1-naphthylamine-6-sulfonic acid alone (SMANS) or together with methoxypolyethlene glycol (SMANP), and characterized by 1H NMR and GPC. Their effects on the rheological behaviors and stability of CWS were investigated. The Cross model was employed to quantitatively describe the rheological behavior of CWS. It was found that amphiphilic copolymer dispersants remarkably reduced the viscosity and improved the stabilization of CWS. The electrostatic repulsion and steric hindrance generated by the copolymer dispersants are believed to play an important role. With the presence of sulfonate groups, both kinds of copolymer dispersants can provide electrostatic repulsion among coal particles after adsorption. For SMANP, the polyethlene glycol (PEG) pendants offer additional steric hindrance to further stabilize the CWS. On the basis of these results, the mechanism of dispersion and stabilization of CWS by the copolymer dispersants was proposed.

Effect of polar/nonpolar groups in comb-type copolymers on cold flowability and paraffin crystallization of waxy oils

Co-reporter:Jun Xu, Shili Xing, Huiqin Qian, Sheng Chen, Xiaoming Wei, Rui Zhang, Li Li, Xuhong Guo

Fuel 2013 Volume 103() pp:600-605

Publication Date(Web):January 2013

DOI:10.1016/j.fuel.2012.06.027

Comb-type poly(maleic alkylamide-co-α-octadecene) copolymers (MACs) with various ratios of polar carboxyl group/nonpolar octadecyl group were synthesized. Upon cooling, MACs change the size and shape of paraffin crystals, and reduce the pour point and yield stress of waxy oils, as observed by rheology, polarizing light microscopy, differential scanning calorimetry, and X-ray diffraction. They also reduce the paraffin crystallization temperature and enthalpies, inhibit the formation of layer structure of paraffin crystals. Their efficiency to improve the cold flowability was found to correlate to the ratio of polar/nonpolar group (r). MAC with r of 0.4, is more effective than the other two in improving the flowability of waxy oils. It seems that MAC2 can balance the competitive assembly behaviors of copolymers with paraffins and asphaltenes. The assembly between the carboxyl and amide groups of MACs with polar aromatic asphaltenes appears to stabilize crude oil by the steric effects of the long-chain alkyl branches of MAC polymers, thereby improving the flowability of paraffin/asphaltene gels formed upon cooling.Highlights• Comb-type poly(maleic alkylamide-co-α-octadecene) copolymers with various ratios of polar/nonpolar group were synthesized. • Effects of copolymers on the cold flowability of waxy oils and crystallization of paraffins were studied. • Copolymer with an appropriate ratio of polar/nonpolar group possesses the best effect on the flowability of waxy oils. • Assembly model of comb-type copolymers interacting with paraffins and asphaltenes in crude oil was presented.