Method for treatment of oily sludge

[0028] The invention relates to a method for treating oily sludge. First, the oily sludge is diluted from a viscous state to a fluid state by the first quenching and tempering treatment, followed by heating and ultrasonic treatment to initially separate water, oil, and mud into three phases , To obtain separated oil and solids, and then use the second quenching and tempering treatment for deep oil-solid separation, and finally, the oil is separated by a horizontal screw centrifugal machine, the sludge solids are dried, standing for precipitation, oil-water layer separation, crude oil Recycle and complete the treatment of oily sludge. In the whole process, two quenching and tempering treatments are carried out according to the characteristics of the sludge, the efficiency of oil washing is higher, and the utilization rate of the medicament is higher. Ultrasonic and mechanical centrifugal methods are also used to speed up the process, further improve the efficiency of oil washing of oily sludge, simple operation, low energy consumption, and achieve the purpose of reducing, harmless, and recycling oily sludge.

[0029] In the following, the present invention will be further described in detail with reference to the accompanying drawings and specific implementation examples in order to clearly understand the technical method of the present invention.

[0030] Such as figure 1 As shown, an oily sludge treatment method of the present invention includes a quenching and tempering treatment part, a heating ultrasonic treatment part and a centrifugal separation treatment part, the obtained sewage is transported to the sewage treatment plant, the heavy oil (crude oil) is returned to the refinery and The sludge is dried and landfilled to prevent it from damaging the environment. The specific implementation steps are as follows:

[0031] (1) A conditioning treatment, adding sludge, water, demulsifier, and flocculant according to a certain proportion, and after being fully mixed by mechanical stirring, the sludge is diluted from a viscous state to a fluid state;

[0032] (2) Heating and ultrasonic treatment: the mud-water mixture after a tempering treatment is ultrasonically treated by a customized heating ultrasonic device, heated to 50°C for 100 minutes, and then taken out. The oily sludge is treated by ultrasonic mechanical vibration and cavitation. The emulsion forms strong turbulence, so that the oil, water, and mud in the sludge overcome the interfacial tension due to friction and separate from each other, especially for the cavitation of the sludge interface, which can quickly separate the oil and solid;

[0033] (3) Secondary conditioning treatment, adding alkaline dispersant and dehydrating agent, performing secondary conditioning treatment on the deep-seated oil that was not completely separated in the previous treatment, and further carrying out oil-solid separation;

[0034] (4) Centrifugal separation, after primary conditioning treatment, ultrasonic treatment and secondary conditioning treatment, the oil in the sludge is fully emulsified and mixed with water under the action of medicament and ultrasonic treatment. Separation, centrifuge for 15min under the condition of 3000r/min, and separate the oil in the sludge from the sludge solid along with the moisture;

[0035] (5) Drying, the sludge solid after centrifugal treatment is in elastic plastic form, and the water content is still higher than 60%. Natural drying or solar drying can be used to dry it, in order to prevent pollution to the surrounding environment , The sludge can be dried in a greenhouse, and the moisture content of the dried sludge is 20%-40%, which can be landfilled or subsequently solidified;

[0036] (6) Oil-water stratification. The liquid after centrifugal separation is composed of water and emulsified oil. Electrolytes or demulsifiers are added to destroy the stability of the emulsified system, thereby achieving the separation of oil and water. The separated oil-water mixture is in the gravity separator. Set aside to settle, after the oil-water layer, the crude oil floating on the upper layer is recovered by using the different density of the oil and water, the recovered crude oil is filtered and sent to the refinery for reuse, and the sewage from the lower layer is sent back to the primary conditioning treatment step for recovery use.

[0037] Moreover, the sludge is heavy oil sludge. Oily sludge, viscous, black, peculiar smell, oil content of 26%.

[0038] Moreover, the mass ratio of each component in the primary conditioning treatment is:

[0039]

[0040] Moreover, the ratio of the sludge to water is 1:5. When the mud-water ratio is 1:5, the washing effect is the best. When the mud-water ratio is too high, the concentration of demulsifiers such as sodium dodecylbenzene sulfonate will decrease, resulting in insignificant demulsification effect, and the oil content of the washed sludge will increase, so a mud-water ratio of 1:5 should be adopted.

[0041] Moreover, the heating temperature is 50℃

[0042] Moreover, the demulsifier is sodium dodecylbenzene sulfonate, the mass fraction of which is 2% of the sludge. Sodium dodecylbenzene sulfonate can destroy the oil-in-water structure in the sludge as a demulsifier, and then disperse the oil-in-water structure through the vibration and cavitation reaction of the ultrasonic vibrator.

[0043] Moreover, the flocculant is polyaluminum chloride. The polyaluminum chloride flocculant makes the water separated from the oil-in-water flocculate into the mud quickly.

[0044] Moreover, the oil-displacing agent is carbonamide.

[0045] Moreover, the mass ratio of each component in the secondary tempering treatment is:

[0046] Dispersant 0.8-1.5g 1-1.7g 1.1-1.9g

[0047] Moreover, the dispersant is sodium silicate, the mass fraction of which is 1.0% of the sludge. As a dispersant, sodium silicate is disturbed by ultrasound and cannot exert the effect of oil-water separation, so it should be added after the ultrasound step.

[0048] Both 2% sodium dodecylbenzene sulfonate and 1.0% sodium silicate are the best mass fractions. Adsorption is prone to occur when the mass fraction of the two is low, but when the concentration of sodium dodecylbenzene sulfonate reaches the critical concentration of micelles, micelles will appear in the solution. When the sodium concentration increases again, a large number of micelles will be formed, and the concentration of free sodium dodecylbenzene sulfonate molecules in the solution will decrease, which will lead to a decrease in the efficiency of washing and deoiling.

[0049] This oily sludge treatment method has carried out the following three specific examples to treat oily sludge with a viscous, black, peculiar smell and an oil content of 26%. The material ratio of the conditioning treatment is shown in the following table.

[0050] Table 1 Material ratio of quenching and tempering treatment

[0051]