聚丙烯酸十八酯-乙酸乙烯酯梳状二元共聚物降凝剂对含蜡原油结晶特性与流变性的影响

doi:10.7503/cjcu20160174

摘要/Abstract

摘要：

在合成聚丙烯酸十八酯(POA)梳状均聚物和聚丙烯酸十八酯-乙酸乙烯酯(POA-VA)系列梳状二元共聚物的基础上, 通过凝点测量、流变实验、差示扫描量热(DSC)分析及偏光显微镜观察等手段研究了POA与POA-VA对长庆含蜡原油结晶特性与流变性的影响. 实验结果表明VA基团的引入调控了POA降凝剂对含蜡原油的作用效果. 当OA与VA单体摩尔比为 3∶1时, POA-VA对含蜡原油的流变改善效果最好, 在降凝剂400 mg/kg剂量下可以降低凝点22 ℃, 平均降黏率为51.45%; 而单体摩尔比升高或降低均会使POA-VA对含蜡原油的流变改善效果变差. 另外, 从POA-VA分子的结晶放热特性和蜡晶微观形貌分析角度, 探讨了VA含量对POA-VA作用性能的影响规律和机理.

关键词: 含蜡原油, 降凝剂, 流变性测量, 梳状聚合物, 极性基团

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

中图分类号:

O631.1⁺1

TrendMD:

杨飞, 肖作曲, 姚博, 李传宪, 孙广宇, 阎孔尧. 聚丙烯酸十八酯-乙酸乙烯酯梳状二元共聚物降凝剂对含蜡原油结晶特性与流变性的影响. 高等学校化学学报, 2016, 37(7): 1395.

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^†. Chem. J. Chinese Universities, 2016, 37(7): 1395.

图/表 10

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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