Si Shaoxiong, Yan Zhong, Gong Zhaobo, Liu Pengfei, Zhang Yumin, Xiang Yu
Experimental Detection Research Institute, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China E-mail:
Chemical Engineering Specialty of Science College, China University of Petroleum, Beijing 102249, China.
Water Sci Technol. 2018 Jan;77(1-2):101-107. doi: 10.2166/wst.2017.513.
In order to meet the latest Environmental Protection Law of China on wastewater discharge standards, this paper studied a pilot-scale micro-flocculation filtration pretreatment process for the treatment of oilfield wastewater. The experiment showed that the removal rate of oil and suspended solids (SS) respectively increased from 91.52% to 95.38% and from 66.42% to 97.19%. After the treatment by the micro-flocculation filtration device, the relevant characteristics of the discharge wastewater satisfied the latest standards continuously. Moreover, the polyaluminum chloride (PAC) dosage was reduced from 200 mg/L to 100 mg/L (50 mg/L in micro-flocculation device and 50 mg/L in the cyclone reactor) at the same time. In order to decrease the degree of scaling in the filter, ceramsite was chosen as the filter material instead of quartz sand that is widely applied in the oilfields. The scaling experiment showed that the HCO, Ca and Mg contents in the extract from quartz sand after the scaling study were increased by 38.05, 35.91 and 0.28 mg/L, respectively. Meanwhile, the HCO, Ca and Mg contents in the extract from ceramsite were only increased by 13.14, 6.26 and 0.27 mg/L, respectively. Therefore, the ceramsite is not so prone to scaling as compared to quartz sand under identical test conditions, which avoided a hardened and impervious filter after operating for some time. These results suggest that the micro-flocculation filtration with the ceramsite as filter media is a suitable pretreatment process for the oilfield wastewater treatment.
为满足中国最新的《环境保护法》对废水排放标准的要求，本文研究了一种中试规模的微絮凝过滤预处理工艺用于处理油田废水。实验表明，油和悬浮固体（SS）的去除率分别从91.52%提高到95.38%以及从66.42%提高到97.19%。经微絮凝过滤装置处理后，排放废水的相关特性持续满足最新标准。此外，同时将聚合氯化铝（PAC）的投加量从200mg/L降至100mg/L（微絮凝装置中为50mg/L，旋风反应器中为50mg/L）。为降低过滤器中的结垢程度，选择陶粒作为过滤材料，而非油田广泛应用的石英砂。结垢实验表明，结垢研究后石英砂提取物中的HCO₃⁻、Ca和Mg含量分别增加了38.05、35.91和0.28mg/L。同时，陶粒提取物中的HCO₃⁻、Ca和Mg含量仅分别增加了13.14、6.26和0.27mg/L。因此，在相同测试条件下，陶粒比石英砂更不易结垢，避免了运行一段时间后过滤器变硬和堵塞。这些结果表明，以陶粒为过滤介质的微絮凝过滤是一种适用于油田废水处理的预处理工艺。
