LP油田沉降罐过渡带原油破乳脱水实验研究

LP油田沉降罐过渡带原油中含有起乳化作用的胶态FeS等成分,导致原油脱水困难,不能满足原油进后续电脱水器的要求;分析了过渡带原油物性、原油组分及采出水组成,对FeS脱除剂及破乳剂的筛选进行优化实验,重点研究了FeS脱除剂与破乳剂联合破乳效果及适应性。结果表明,筛选出的FeS脱除剂BLJ-01对FeS有很好的溶解效果,体积分数3%的FeS脱除剂BLJ-01和质量浓度800 mg/L的破乳剂X-75联合使用,55℃下可有效去除沉降罐过渡带原油中FeS,沉降罐过渡带原油脱水率达85.78%;BLJ-01与X-75配合使用适应性较强,对含水率超过40%的P2联合站沉降罐过渡带原油脱水率均可达80%以上,且在弱酸或弱碱性条件下都可以表现出优良的破乳效果,也适用于SJ站沉降罐过渡带原油的破乳脱水,并能显著降低破乳剂使用量。

聚合物及固体颗粒对原油乳状液稳定性影响机制研究

为了探明油田作业返排残液影响原油采出液脱水的原因,以返排残液中最常见的非离子型聚丙烯酰胺(NPAM)及瓜胶为聚合物代表,以石英砂为颗粒物代表,研究了单一聚合物、单一颗粒物及聚合物与颗粒物共存影响原油乳状液稳定性的机理。结果表明,单一聚合物对乳状液稳定性影响中,聚合物质量浓度增加至1 000 mg/L,乳状液脱水率降低至0%,粒径分布峰值均小于10μm,黏度成倍增长,含瓜胶乳状液黏度增加了2.80倍,含NPAM黏度增加了1.82倍,平衡界面张力下降,油水界面黏弹性增加且弹性模量是黏性模量的4~5倍,此时界面膜以弹性膜为主,界面膜强度增加,乳状液稳定性增加。单一颗粒物对乳状液影响为含固量增加至1%,乳状液脱水率降低了9.90%,黏度增加了46.36%,油水界面张力降低了9.10%左右。聚合物和固体颗粒叠加影响作用于乳状液,含固量1%且聚合物质量浓度增加时,脱水率从54.50%降低至0%,黏度增加了2.58倍,粒径分布峰值降低了74.97%;这些现象说明乳状液中聚合物和固体颗粒增多,脱水难度增加,乳状液稳定性增加。

Nitrification and denitrification in biological activated carbon filter for treating high ammonia source water

Since the ammonia in the effluent of the tradi-tional water purification process could not meet the supply demand,the advanced treatment of a high concentration of NH4+-N micro-polluted source water by biological activated carbon filter(BACF)was tested.The filter was operated in the downflow manner and the results showed that the remov-ing rate of NH_(4)^(+)-N was related to the influent concentration of NH_(4)^(+)-N.Its removing rate could be higher than 95%when influent concentration was under 1.0 mg/L.It could also decrease with the increasing influent concentration when the NH_(4)^(+)-N concentration was in the range from 1.5 to 4.9 mg/L and the dissolved oxygen(DO)in the influent was under 10 mg/L,and the minimum removing rate could be 30%.The key factor of restricting nitrification in BACF was the influent DO.When the influent NH_(4)^(+)-N concentration was high,the DO in water was almost depleted entirely by the nitrifying and hetetrophic bacteria in the depth of 0.4 m filter and the filter layer was divided into aerobic and anoxic zones.The nitrification and degradation of organic matters existed in the aerobic zone,while the denitrification occurred in the anoxic zone.Due to the limited carbon source,the denitrifica-tion could not be carried out properly,which led to the accu-mulation of the denitrification intermediates such as NO_(2)^(−).In addition to the denitrification bacteria,the nitrification and the heterotrophic bacteria existed in the anoxic zone.

Effects of deep soil mixing on existing shield tunnels in soft soil ground

To mitigate the impact of adjacent construction on existing shield tunnels,deep soil mixing(DSM)has been widely used to reinforce the soft soil ground around shield tunnels.However,the construction of DSM may cause the movement of existing shield tunnels under soft soil and sensitive ground conditions,and reasonable installation parameters will reduce the impact of DSM construction on the existing shield tunnels.Based on the field tests of DSM installation parameters and a program of field measurements of existing shield tunnels during the DSM construction in Suzhou,the reasonable installation parameters of DSM were selected,and the movement of soil behind the soil mixing walls(SMWs)during multirow DSM installation was investigated.The movement of the shield tunnels caused by DSM construction were discussed in detail.The field test results showed that the DSM columns installed at a higher speed and a lower water-cement ratio enlarged the movement of the surrounding soil.The DSM should be installed at a lower speed and a higher watercement ratio to reduce the movement of the shield tunnels.The field measurement results showed that the displacement of the tunnel lining was primarily caused by the construction of DSM zones beside the shield tunnels,which led to vertical compression and horizontal expansion of the tunnel lining.The construction of DSM immediately above the shield tunnels caused uplift to the tunnels.In addition,the deformed shapes of the two shield tunnels were asymmetric,and the displacement of the spring lining was larger than that of the crown.By taking the reasonable installation parameters of DSM and under the protection of the SMWs,the deformation of the shield tunnels caused by the construction of DSM was effectively controlled,and the maximum displacement was within the control value of the shield tunnels in this study.