Method and device for preventing electrical desalting tank oil sludge sedimentation by means of ultrasonic waves

Abstract

The invention belongs to the technical field of petrochemical engineering applying ultrasonic waves, and particularly relates to a method and device for preventing electrical desalting tank oil sludgesedimentation by means of ultrasonic waves. According to the method, crude oil is mixed and then enters an ultrasonic wave acting device, and ultrasonic waves formed by a mixing action manner of parallel correlation ultrasonic waves and pipeline reflection ultrasonic waves are formed in the ultrasonic wave acting device through an ultrasonic wave action area structure; and a standing wave field effect is achieved through ultrasonic superposition, the ultrasonic reflection generates infinite extension, the mixed crude oil is subjected to ultrasonic treatment through a combined action of a standing wave field and the dead-angle-free coverage infinite extending, and the mixed crude oil enters an electric desalting tank for electric desalting after the treatment is finished. The method and the device are used for solving the production technical problem of oil sludge sedimentation of the electric desalting tank, and the continuous production of the electric desalting tank in 3-4-year long-period production process of an oil refinery; and the oil sludge sedimentation removing maintenance operation which conducted once a year due to abnormal shutdown of the electric desalting tank is avoided, the back washing frequency of the electric desalting tank is reduced, the electric desalting operation is simplified, and the electric desalting effect is improved.

Description

technical field [0001] The invention belongs to the technical field of ultrasonic application in petrochemical industry, and in particular relates to a method and a device for preventing sludge deposition in an electric desalination tank by ultrasonic waves. Background technique [0002] Electric desalting is the first pretreatment process for crude oil entering the refinery from the oil field. The electric desalting process requires water injection to remove the water-soluble inorganic salts contained in the crude oil, mainly to remove NaCl salts. In the electric desalting tank, under the action of the high-voltage electric field, the crude oil mixed with water will not only release water and water-soluble inorganic salts, but the bottom of the electric desalting tank is prone to deposit a large amount of non-water-soluble semi-solid oil sludge. Oil replacement—steam steamer—air replacement—manual cleaning—sludge outsourcing and other sludge treatment processes. In the pas...

AI Technical Summary

Problems solved by technology

If the electric desalination tank is silted for about one year, if the continuous production of electric desalination is continued, the backwash water will carry a large amount of sludge, resulting in a large amount of recycled waste oil; , the production of electric desalination is becoming more and more abnormal, and the oil content of electric desalination drainage will also increase significantly, which will also lead to the recovery of a large amount of dirty oil in sewage treatment plants; Take the 4-year long-cycle production of desalination tanks as an example. In 4 years, 42,000 tons of heavy dirty oil cannot be processed, and heavy dirty oil with high water content is also difficult to refinish and process, resulting in large refining losses. It is also a production problem that has yet to be solved.

[0005] As more and more sludge is deposited at the bottom of the electric desalination tank, the effective volume of the electric desalination tank is getting smaller and smaller, the settling time of oil-water separation is getting shorter and shorter, and the time and space of oil-water separation can no longer meet the requirements of normal production. Electric desalination processes are becoming increasingly dysfunctional, causing large and potentially detrimental effects on refinery production

The abnormal operation of electric desalination leads to the increase of salt and water content in crude oil after electric desalination, the electric desalting tank current rises and the power consumption increases, resulting in increased energy consumption of crude oil post-processing, serious fouling, equipment corrosion, increased catalyst consumption, etc., and electric desalting tank oil sludge Problem creates potential financial loss for refinery

[0006] During the production process, the electric desalination tank is designed to use backwashing operation to slow down the deposition of sludge in the electric desalination tank. This routine operation: the daily backwashing operation increases the workload of the operator and increases the operating cost; frequent backwashing leads to Backwash drainage carries a large amount of sludge, which increases the amount of heavy oil and the cost of treatment; frequent backwash causes backwash drainage to carry a large amount of sludge, which increases the cost of sewage treatment; backwash frequency or tediousness increases with sludge accumulation The backwashing operation cannot meet the long-term production requirements of the 3-4 year overhaul of the electric desalination tank, and cannot solve the current production problem of the sludge accumulation in the electric desalination tank

[0007] In actual production, in order to solve the production technical problem of oil sludge deposition in a petrochemical refinery, the volume of the electric desalination tank was changed from 200m 3 increased to 800m 3 , this method brings new production technical problems: the larger the electric desalting tank, the smaller the linear velocity, and the mechanical impurities such as mud, sand, soil, oil-soluble salts contained in crude oil are easy to deposit on the bottom of the electric desalting tank, resulting in sludge The problem of silting is more serious, and the operation of removing sludge once a year has deteriorated to three times a year; the transfer of solid waste is also a major problem in the current environmental protection work; more sludge will be washed out in each backwash, and production has to be Arrange backwashing once every week on average, the backwashing water volume is about 70t / h, and each tank of the two-stage electric desalination tank is backwashed for 30 minutes, which increases the workload of production personnel and operating costs

[0008] The existing conventional electric desalination tank backwashing technology to solve the sludge deposition of the electric desalination tank cannot solve the problem of the deposition of the electric desalination tank produced by the refinery with a long period of 3-4 years

In the reality that the sludge in the electric desalination tank affects the long-term production, a certain electric desalination tank manufacturer adopts a technical improvement plan for the electric desalination tank of a certain oil refinery by laying PTFE plates on the bottom of the tank and adding backwash nozzles. The surface of the fluorine plate is smooth so that the sludge is not easy to deposit on the bottom of the electric desalination tube, and the number of backwash nozzles is increased to strengthen the strength of the backwash. The problem with this device is that it has no obvious effect on improving the production problem of sludge accumulation in the electric desalination tank. Cannot extend the maintenance cycle of sludge removal once a year

[0009] Prior art, CN02213619-crude oil ultrasonic wave-electric field combined desalting device, CN03139172.9-method and device for demulsifying oil-water emulsion through the joint action of downstream and counter-current ultrasonic waves, CN03253324-demulsifying device for oil-water emulsion, CN201020573668-a Single feed ultrasonic-electric desalination combined device, CN201020575233-a multi-feed parallel ultrasonic-electric desalination combined device, CN201721734500-an electric desalination device and CN201120086725-ultrasonic demulsification pipeline action device all solve the problem of electric demulsification. The technical solutions to the problem of oil-water demulsification in desalination all have the phenomenon that the ultrasonic wave generated by the ultrasonic device is single and the utilization rate of the ultrasonic wave is low

Up to now, there is no effective technical solution to solve the sludge deposition in the electric desalination tank, and there is no public technical solution to prevent the sludge deposition in the ultrasonic electric desalination tank

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