复配菌对原油除蜡降黏效果分析

Effect of Compound Bacteria on Wax Removal and Viscosity Reduction of Crude Oil

为提高含蜡原油流动性能,从辽河油田附近经受原油污染的土壤中筛选出两株原油降解菌。经过16S rRNA基因序列比对鉴定,菌株为纤维微菌属(Cellulosimicrobium sp.)和假单孢菌(Pseudomonas sp.),命名为7^#和12^#。将筛选出的7^#菌与12^#菌优化复配使用,研究结果表明:复配菌对液体石蜡有乳化效果,当复配菌体积比为1∶1时,乳化率最高达到77.5%;最适的生长温度为35~40℃,p H=6~8,最佳接种量(体积分数)为4%,复配菌体积比为1∶1,且培养基在初始pH,即pH=7时复配菌生长状态最佳。复配菌在37℃,pH=7条件下对原油处理7 d后,除蜡率为61.32%,降黏率达到31.58%;显微镜观察蜡晶变小,进一步说明菌株能够降解石蜡,破坏蜡晶结构,提高含蜡原油的流动性能。

In order to improve the flow performance of waxy crude oil, two strains which can degrade crude oil were isolated from the oil contaminated soil near Liaohe Oilfield. The strains were identified as Cellulosimicrobium sp. and Pseudomonas sp., named 7^# and 12^# by 16 S rRNA gene sequence analysis. The results showed that the compound bacteria from 7^# bacteria and 12^# bacteria could emulsify the liquid paraffin. When the volume ratio of 7^# bacteria to 12^# bacteria was 1∶1, the highest emulsification rate reached up to 77.5%. Under the optimal conditions of temperature 35~40 ℃, p H value 6~8, inoculum volume ratio 4%, volume ratio of 7^# bacteria to 12^# bacteria 1∶1, the best growth of the compound bacteria was obtained at initial pH=7. After the crude oil was treated for 7 days with the compound bacteria at 37 ℃ and pH=7, the removal rate of wax was 61.32% and the rate of viscosity reduction reached up to 31.58%. Through microscope observation, wax crystals became smaller, further indicating that the strain could degrade the wax, destroy the structure of wax crystals and improve the flow performance of waxy crude oil.