干化罐底油泥的溶剂萃取-海水洗涤工艺

为节约淡水资源、拓展海水的直接利用途径,采用热化学水洗处理技术开展了基于海水洗涤的罐底油泥处理试验研究. 结果表明:干化罐底油泥(水含量为9.8%、油含量为25.6%、固含量为64.6%,均以w计)不宜直接进行热化学洗涤,需采用轻油(120#溶剂油)进行萃取预处理,萃取后残油量(干基,以w计)为18.8%. 适宜的洗涤液为海水溶液,其ρ(TX-10)(TX-10为壬基酚聚氧乙烯醚)为10 g/L. 液固质量比为5、洗涤温度为60 ℃、搅拌速率为180 r/min、搅拌时间为30~40 min是洗涤萃取残泥的适宜条件,该条件下萃取后的残油量为2.80%. 二级海水洗涤可使残油量降至0.23%,满足GB 4284—1984《农用污泥中污染物控制标准》. 在洗涤废水再利用试验中,为维持洗涤废水的脱油能力,可在每L洗涤废水中补加1 g TX-10. 研究显示,溶剂萃取-海水洗涤工艺可有效处理干化罐底油泥. 

Solvent Extraction-Seawater Washing of Dried Oily Sludge from Crude Oil Tank

In order to save fresh water and expand the use of seawater, thermo-chemical seawater washing for oily sludge disposal was investigated. It was observed that the dried oily sludge from a crude oil tank, which contains 9.8% moisture, 25.6% oil and 64.6% solid, could not be well disposed directly by thermo-chemical washing, when sludge was not pre-extracted. The extraction solvent was naphtha (such as 120# solvent naphtha), and the oil content of the extracted sludge was about 18.8% (dry basis). Seawater was more effective than fresh water during the washing process. The proper washing liquid was seawater with 10 g/L nonylphenol polyeothoxylates (e.g.TX-10). With a mass ratio of liquid to extracted sludge of 5, operation temperature of 60 ℃, stirring rate of 180 r/min and stirring duration of 30-40 min, the oil content in the sludge washed once was about 2.80% (dry basis), and that in the sludge washed twice was about 0.23% (dry basis), which was less than the oil control limit of 0.30% (dry basis) for mud discharge according to China's national standard GB 4284-1984, “Contaminant Control Standard of Sludge for Agriculture in China”. Moreover, in the experiment on reuse of washing wastewater, 1 g of TX-10 was added per liter of waste water in order to maintain washing efficiency. The technique with solvent extraction and seawater washing is efficient for dried oily sludge of tank bottom, and has a prospective application on the fields of seawater direct use and oily sludge disposal.