Influence of Poly-octadecylacrylate-vinylacetate Comb-like Copolymers on Rheological and Crystallization Characteristics of Waxy Crude Oil†

doi:10.7503/cjcu20160174

Abstract

Abstract:

The comb-like copolymers, which are used as pour point depressants(PPDs) for waxy crude oil, polyoctadecylacrylate(POA) and poly-octadecylacrylate-vinylacetate(POA-VA) were synthesized by solvent free-radical polymerizing method and characterized by ¹H NMR and gel permeation chromatography(GPC). The performance of comb-like polymers on waxy crude oil were investigated via pour point measurement, rheological test, differential scanning calorimetry method and polarized microscopic observation. The results show that the introduction of VA group controls the pour point depressing ability of POA. In particular, POA-VA-4[n(OA)∶n(VA)=3∶1] is the best PPD in optimizing rheological properties of the waxy crude oil. After the addition of 400 mg/kg POA-VA-4, compared with original waxy crude oil, the pour point of crude oil decreases by 22 ℃ and its average viscosity decreases by 51.45%. Based on the crystallization exothermic characteristics and wax crystal morphology of crude oils after the addition of POA and POA-VA, the mechanism of the effects of VA content on the performance of comb-like copolymer PPDs was proposed.

Key words: Waxy crude oil, Pour point depressant, Rheological measurement, Comb-like copolymer, Polar functional group

CLC Number:

O631.1⁺1

TrendMD:

YANG Fei, XIAO Zuoqu, YAO Bo, LI Chuanxian, SUN Guangyu, YAN Kongyao. Influence of Poly-octadecylacrylate-vinylacetate Comb-like Copolymers on Rheological and Crystallization Characteristics of Waxy Crude Oil^†[J]. Chem. J. Chinese Universities, 2016, 37(7): 1395.

Figures/Tables 10

References 26

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Copolymer	Feeding molar fraction of OA(%)	Real molar fraction of OA(%)	M_w	M_n	M_w/M_n
POA			19977	7293	2.74
POA-VA-1	90	92	33658	10685	3.15
POA-VA-2	87	88	34522	6928	4.98
POA-VA-3	83	84	32700	6527	5.01
POA-VA-4	75	77	35766	6185	5.78
POA-VA-5	50	56	33893	7596	4.46

Copolymer	Feeding molar fraction of OA(%)	Real molar fraction of OA(%)	M_w	M_n	M_w/M_n
POA			19977	7293	2.74
POA-VA-1	90	92	33658	10685	3.15
POA-VA-2	87	88	34522	6928	4.98
POA-VA-3	83	84	32700	6527	5.01
POA-VA-4	75	77	35766	6185	5.78
POA-VA-5	50	56	33893	7596	4.46

Copolymer	Apparent viscosity/(Pa·s)					Average viscosity reducing rate(%)
Copolymer	11.58 s^-1		20.35 s^-1	49.95 s^-1	101.6 s^-1	199.6 s^-1
Non-added	0.801	0.396	0.226	0.177	0.149
POA	0.267	0.202	0.139	0.116	0.102	41.78
POA-VA-1	0.243	0.184	0.128	0.108	0.096	46.29
POA-VA-2	0.259	0.194	0.133	0.112	0.099	43.86
POA-VA-3	0.268	0.198	0.135	0.113	0.100	43.09
POA-VA-4	0.222	0.168	0.116	0.097	0.086	51.45
POA-VA-5	0.310	0.228	0.156	0.132	0.117	33.89

Copolymer	Apparent viscosity/(Pa·s)					Average viscosity reducing rate(%)
Copolymer	11.58 s^-1		20.35 s^-1	49.95 s^-1	101.6 s^-1	199.6 s^-1
Non-added	0.801	0.396	0.226	0.177	0.149
POA	0.267	0.202	0.139	0.116	0.102	41.78
POA-VA-1	0.243	0.184	0.128	0.108	0.096	46.29
POA-VA-2	0.259	0.194	0.133	0.112	0.099	43.86
POA-VA-3	0.268	0.198	0.135	0.113	0.100	43.09
POA-VA-4	0.222	0.168	0.116	0.097	0.086	51.45
POA-VA-5	0.310	0.228	0.156	0.132	0.117	33.89