摘要: |
采用熔融共混法制备不同共混浓度的乙烯-醋酸乙烯酯(EVA)/沥青质颗粒复合降凝剂,通过流变实验和凝点实验,探究EVA/沥青质复合降凝剂对青海原油低温流变性的影响,考察加剂前后原油的结晶特性和蜡晶形貌的变化情况,分析共混浓度对复合降凝剂流变改善效果的影响。结果表明:沥青质颗粒的引入增强了EVA降凝剂的成核作用,提高了含蜡原油的析蜡点;EVA/ASP复合降凝剂以平均粒径为2 μm的复合颗粒形式分散于油相中,在降温过程中为蜡分子提供异相成核模板,进而显著改善析出蜡晶的形貌和含蜡原油的低温流变性;随着复合降凝剂中沥青质质量分数的提高,复合降凝剂作用效果先提高后降低,在50 mg/kg的加剂量下,EVA/10% ASP对含蜡原油具有最佳的流变改善效果,比纯EVA降凝剂凝点进一步降低3 ℃,胶凝点进一步降低2.2 ℃。 |
关键词: 含蜡原油 沥青质颗粒 复合降凝剂 流变性 |
DOI:10.3969/j.issn.1673-5005.2022.02.021 |
分类号::TE 832 |
文献标识码:A |
基金项目:国家自然科学基金项目(51904327、51774311);中国博士后科学基金项目(2019TQ0354、2019M662468);中央高校基本科研业务费专项(20CX06020A) |
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Influence of EVA/asphaltene composite pour point depressant on rheological properties of Qinghai waxy crude oil |
YANG Fei, XIA Xue, ZHANG Xiaoping, LI Chuanxian, YAO Bo, SUN Guangyu
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(College of Pipeline and Civil Engineering in China University of Petroleum(East China), Qingdao 266580, China)
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Abstract: |
The melt blending method was used to prepare EVA/asphaltene particle composite pour point depressants with different blending concentrations. Through rheological and pour point experiments, the effect of EVA/asphaltene composite pour point depressant on the low-temperature rheology of Qinghai crude oil was explored. The change of crystalline characteristics and wax crystal morphology of crude oil before and after the addition was investigated, and the effect of blending concentration on rheological improvement of composite pour point depressants was analyzed. The results show that the introduction of asphaltene particles enhances the nucleation effect of EVA pour point depressant and improves the wax precipitation point of waxy crude oil. The EVA/ASP composite pour point depressant is dispersed in the oil phase as composite particles with an average particle size of 2 μm. It provides a heterogeneous nucleation template for wax molecules during the cooling process, which significantly improves the morphology of precipitated wax crystals and the rheology of waxy crude oil at low temperature. With the increase of the asphaltene mass fraction in the compound pour point depressant, the effect of the compound pour point depressant increases first and then decreases.At the dosage of 50 mg/kg, EVA/ASP-3 has the best rheological improvement effect on waxy crude oil, which further reduces the pour point by 3 ℃ and gelation point by 2.2 ℃ compared with pure EVA pour point depressant. |
Key words: waxy crude oil asphaltene particles composite pour point depressant rheology |