Pretreatment of oily sludge is the key to determine whether oily sludge can be efficiently utilized. The current domestic and international oil sludge pretreatment technologies, including: extraction technology, quenching and tempering technology, and reinjection. Profile control technology, chemical hot water washing method, ultrasonic treatment technology, etc.
Oily sludge is mainly produced in crude oil production, oil and gas storage and transportation, and crude oil storage and sewage treatment in refineries. According to the data, China's petroleum resources are concentrated in the eight major basins of Bohai Bay, Songliao, Tarim, Ordos, Junggar, Zhujiangkou, Qaidam and East China Sea Shelf.
According to its source, oily sludge can be generally divided into three types: floor sludge, tank bottom sludge and “refinery three mud”. Oily sludge pollution generally has the characteristics of high oil content, high viscosity and difficulty in dehydration. Oily sludge is a multi-phase system. It is generally composed of oil-in-water, water-in-oil and suspended solids.
The oily sludge has a high oil content, the water is fully emulsified, and the direct treatment cost is high. Moreover, the oil content in the oily sludge is a valuable resource, so the appropriate technology should be adopted according to the oil content in the sludge during the sludge treatment. At present, the treatment of oily sludge is usually pretreated to separate oil and water, and a part of crude oil is recovered to realize resource recycling. After the pretreatment, the sludge deep treatment technology is used to further realize the harmlessness and resource utilization of the oily sludge.
