炼厂浮渣的超声强化脱水处理

Ultrasound-enhanced dewatering of oil refinery scum

针对炼厂浮渣乳化严重、脱水减量困难的问题,采用超声—离心分离工艺对其进行强化脱水处理。比较了单独离心、絮凝—离心和超声—离心3种方式对浮渣的脱水效果,考察了超声时间和超声温度对浮渣脱水效果的影响,表征了超声处理前后浮渣的微观结构,探讨了超声强化脱水的机理。实验结果表明:在未加任何药剂、超声频率25 kHz、超声功率240 W、超声时间5 min、超声温度30℃的最佳工艺条件下,浮渣脱水率为89.68%,较单独离心和絮凝—离心工艺分别提高了7.77和2.99百分点,底泥含水率为82.94%。表征结果显示:超声机械振动作用破坏了固体颗粒空隙和内部沟壑结构,降低了对油滴的吸附,促进了油滴凝并,实现了原油轻质化,说明超声作用可促进浮渣脱水。

Aiming at the problems of serious emulsification and difficult dehydration reduction,the oil refinery scum was treated by enhanced dewatering process of ultrasonic-centrifugation separation.The dewatering processss of single centrifugation,flocculation-centrifugation and ultrasonic-centrifugation were compared.The effects of ultrasonic time and ultrasonic temperature on scum dewatering were investigated.The microstructures of the scum before and after treatment were characterized and the mechanism of ultrasound-enhanced dewatering was discussed.The experimental results indicate that under the optimum conditions of without any flocculant,ultrasonic frequency 25 kHz,ultrasonic power 240 W,ultrasonic time 5 min and ultrasonic temperature 30℃,the scum dewatering rate is 89.68%,which increased 7.77 and 2.99 percent compared to the single centrifugation and flocculation-centrifugation processes,respectively,and the moisture content of the dewatered sludge is 82.94%.The characterization results show that the solid particle voids and internal trench structures are destructed due to the ultrasonic mechanical vibration,which reduces the adsorption of oil.It also promotes the merging of smaller oil droplets into bigger ones and makes the oil lightening,which indicates that the dewatering of the scum can be improved by ultrasonic irradiation.