纳米KH550-C18/SiO2复合粒子稠油降黏剂的制备及应用性能

Preparation and application property of viscosity reducer with nano-sized KH550-C18/SiO2 composite particles for heavy oil

关键词:  稠油  降黏剂  蜡晶  成核剂  纳米二氧化硅  表面改性 

Key words:  heavy oil  viscosity reducer  wax crystal  nucleating agent  nano-silica  surface modification

摘要:

通过硅烷偶联剂KH550和十八酸对纳米SiO₂进行复合疏水改性,制备了一种新型纳米KH550-C18/SiO₂复合粒子降黏剂。采用红外光谱(FT-IR)、热重分析(TG)、透射电镜(TEM)、扫描量热分析(DSC)等手段对改性后纳米SiO₂粒子的结构和性质进行分析表征。将其应用于大庆高蜡稠油进行降黏性能测试,研究了改性剂用量配比和降黏剂加入量对降黏效果的影响。结果 表明,复合改性后,颗粒团聚程度减轻,在有机介质中能均匀稳定分散；纳米KH550-C18/SiO₂复合粒子表面由于接枝了含有极性基团的有机长链,能同时起到改善蜡质结晶行为和抑制胶质、沥青质形成大尺寸聚集体的作用；在最佳合成条件和最佳加入量时,该降黏剂在40 ℃的表观降黏率和净降黏率分别达66.91%和40.32%,优于市售EVA降黏剂。 

Abstract:

A novel nano-silica composite particle viscosity reducer for heavy oil was prepared by modifying the surface of nano-silica with silane couping agent KH550 and stearic acid. The structure and property of modified nano-silica particles were characterized and analyzed by FTIR, TG, TEM and DSC. Its viscosity reducing effect for high-wax heavy oil in Daqing oilfield was studied, and the effects on viscosity reducing were investigated by the ratio of modifier and dosage of viscosity reducer. After surface modification, the nano-silica composite particles were low agglomerated and could be dispersed in organic medium stably. Because the nano-sized KH550-C18/SiO₂ composite particles were surface grafted with organic long chain containing polar group, they could change wax’s crystallization behavior and prevent colloid and asphaltene forming large-sized aggregate. Under the optimal synthesis conditions and the best addition, its apparent viscosity reducing ratio and pure viscosity reducing ratio reached 66.91% and 40.32% respectively at 40 ℃, which is better than the commercial viscosity reducer EVA.