含聚污水中乳化活性亚组分的分析及污水稳定性研究

Study on the Emulsifiable Active Subfractions and Stability of Polymer-flooding Produced Water

用石油醚和三氯甲烷依次萃取含聚污水中的油分,然后用石油醚沉淀及甲醇/异丙醇抽提,将两个组分分成六个亚组分。表征了六个亚组分的结构组成,研究了亚组分的乳化性能,考察了水相组成对高酸值亚组分SF31所形成乳状液稳定性的影响。研究结果表明,固体亚组分SF41和SF42的H/C低,相对分子质量高,杂原子含量高,金属钙、铁含量高(SF42相对分子质量高达4 533,杂原子含量25.3%,钙、铁含量分别达到2 357 mg/kg、455.8 mg/kg),液体亚组分SF1和SF31酸值高(SF31酸值高达23.9 mg KOH/g),这些亚组分都有很强的乳化能力,在一定浓度范围内,乳化活性弱的亚组分SF2对乳化活性强的亚组分的乳化有一定的抑制作用,酸值高的亚组分是导致含聚污水油含量高的主要因素。当水相HPAM含量超过200 mg/L时,乳状液很稳定;盐含量超过1 800 mg/L以后,含HPAM的乳状液稳定性增强,盐含量超过7 000 mg/L后,Zeta电位变成正值。

The oily substances (OSs) in the produced water from a polymer flooded reservoir of Gud-ao,Shengli, were extracted by petroleum ether and tri-chloromethane successively. Then, the two fractions were separated into six subfractions based on polarity by using solvent deposition and extraction. The composition and structure of these subfractions were characterized by elemental analysis, acid number and molecular weigh. The emulsifying activity of subfactions was studied and the factors that influence the stability of produced water emulsion, such as hydrolyzed polyac-rylamide ( HPAM) content, salinity were investigated. High heteroatom content (25.3% for SF42),high molecular weigh (4533 for SF42),high metal content ( Ca 2357 mg · kg-1and Fe455.8mg·kg-1 for SF42),low H/C ratio, and strong emulsifying capacity are observed for solid subfractions SF41 and SF42 at low concentrations. SF31 and SF1, which contributed to the stability of polymer-flooding produced water, had higher acid values (23. 9mg KOH · g-1 for SF31 ) and stronger emulsifying activity than SF2 which had weaker emulsifying activity. The emulsion was extremely stable when HPAM concentration surpassed 200mg · L-1. The emulsion stability increased as NaCl concentration above 1800mg · L-1,and Zeta-potential became positive as NaCl concentration up to 7000mg · L-1 in the present of HPAM.