生物复合型破乳剂破乳特性研究

摘要

The use of microbial de-emulsifier is limited for its low de-emulsification activity,instability and sen-sitivity to environmental factors.To solve this problem,two superior strains（Bacillus mojavensis,Bacillus subtilis）were cultured in a mineral salt medium to obtain a microbial compound de-emulsifier with high capa-bility of de-emulsification.The cell culture could demulsify the O/W model emulsion completely in 48 h at room temperature.Comparing with that of the single strain culture,the fermentation process of the mixed culture was shortened more than 6 h.With less addition volume,the mixed culture showed higher de-emulsification activity and stability.The microbial compound de-emulsifier kept high de-emulsification activity in the emulsion with different pH value ranged from 3-7.Thermostability was detected.When the emulsion temperature varied from 20-120℃,changing rate of the oil drain rate was under 15%.After the strains were mixed cultured,the me-tabolites produced during the fermentation process still took the main function of de-emulsifiction.The superna-tant remained 87%de-emulsification ability of the cell culture while the bacterial cells could hardly break the e-mulsion.Comparing with the widely used chemical ones,the microbial compound de-emulsifier has almost the same effectiveness in dealing with the oil-bearing waste water from Daqing oilfield.Compounding microbial de-e-mulsifiers is an effective way to enhance their demulsification abilities.%为解决现有生物破乳剂破乳效率低、稳定性差、易受环境影响、难以大规模生产的问题,将具有破乳效果的莫海威芽孢杆菌（Bacillus mojavensis）、枯草芽胞杆菌（Bacillus subtilis）在改进的无机盐液体培养基中混合培养,得到了一种高效生物复合型破乳剂.生物复合型破乳剂全培养液在室温下,接触时间48h可使O/W型模型乳状液完全破乳.与单一菌株的全培养液相比,缩短了发酵时间（提高6h以上）,降低了破乳剂投加量,提升了破乳活性和稳定性.乳状液pH值为3～7的条件下,生物复合型破乳剂可维持较高破乳活性.具有良好耐温性,乳状液温度在20～120℃,破乳剂排油率变化在15%以内.复合后,生物破乳剂仍主要依靠发酵过程中产生代谢产物破乳,上清液排油效果为全培养液的87%,菌体悬液几乎不具有破乳活性.与目前广泛使用的化学破乳剂相比,对大庆油田含油废水的处理效果基本接近.微生物破乳剂的复合是提高破乳活性的有效手段.