CN213141727U

CN213141727U - Treatment system for electric desalting backwashing wastewater

Info

Publication number: CN213141727U
Application number: CN202021803063.8U
Authority: CN
Inventors: 王晓阳; 谢晓朋
Original assignee: Beijing Hanqi Environment Technology Co ltd
Current assignee: Beijing Hanqi Environmental Technology Co.,Ltd.
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2021-05-07
Anticipated expiration: 2030-08-25

Abstract

The application relates to a processing system of electric desalination backwash wastewater, relates to sewage treatment technical field, has solved the problem that produces a large amount of backwash water when current with dilution method processing backwash wastewater. Along the flowing direction of backwashing wastewater, the treatment system comprises a demulsification unit, a coagulation unit, a flocculation unit and an air flotation unit which are sequentially communicated; the air flotation unit is communicated with a pulse container tank, the top of the pulse container tank is provided with a compressed air injection pipe and a clear water injection pipe, the bottom of the pulse container tank is provided with a water outlet pipe, and the water outlet pipe is communicated with the water inlet end of the air flotation unit. This application has avoided backwash water volume to increase and a series of problems that bring, and pollutant such as a large amount of dregs of fat, suspended solid and inorganic matter in the backwash wastewater of getting rid of that can be fine, and the treatment effeciency is better.

Description

Treatment system for electric desalting backwashing wastewater

Technical Field

The application relates to the technical field of sewage treatment, in particular to a treatment system for electric desalting and backwashing wastewater.

Background

Crude oil produced from the oil reservoir is accompanied by water (water is soluble in oil or present in an emulsified state) and inorganic salts (NaCl, MgCl)₂And CaCl₂Etc.) the presence of these substances is very hazardous to the process and is therefore removed by electro-desalination. The electric desalting is a pretreatment process before the crude oil enters distillation, and inorganic substances can be removedThe salts are dissolved in water and then removed together. The specific process comprises the following steps: injecting a certain amount of fresh water into the crude oil, adding a demulsifier, wherein the demulsifier can break an emulsion film and remove the emulsion state of water, and meanwhile, most of inorganic salt is dissolved in water, so that the water in the crude oil is converged under the action of an electric field, the tiny water drops are coalesced into big water drops, and the big water drops and the oil in the crude oil are separated under the action of gravity, thereby realizing the oil-water separation. Since most inorganic salts are soluble in water, desalination and dehydration can be performed simultaneously in the case of electric desalination.

In the electric desalting process, after an electrode plate generating an electric field is used for a period of time, a substrate is stained with pollutants containing a small amount of crude oil, inorganic salts, sulfides, phenols, suspended particulate matters, various organic matters, demulsifiers and the like, and the electric desalting effect is deteriorated and the efficiency is reduced if the electrode plate is not cleaned, so that the used electrode needs to be washed by clean water regularly, and the water generated by washing the electrode is called electric desalting backwashing wastewater.

The electric desalting backwashing wastewater contains a large amount of oil residues, a large amount of suspended matters and various organic matters such as volatile phenol, petroleum substances and the like, and has a large salt content, and based on the characteristics of the electric desalting backwashing wastewater, the water cannot be directly discharged into a sewage treatment system of a sewage treatment plant and needs to be treated. The most common treatment mode is that the electric desalting backwashing wastewater is sent to a regulating tank for buffering, then is mixed with all the sewage in the oil refining area, and finally is discharged into a buffer tank. However, the method for electrically desalting and backwashing wastewater by a dilution method has certain defects: when the quality of crude oil is poor, the backwashing frequency of the electrodes is increased, so that the backwashing water quantity is increased, and the backwashing water quantity is increased, so that a series of problems are caused: 1. the conditioning tank may not be sufficient to store this much backwash wastewater; 2. the mixed wastewater of the refinery may not be enough to dilute the backwash wastewater; 3. impact the treatment system of the sewage treatment plant.

SUMMERY OF THE UTILITY MODEL

In order to avoid a series of problems caused by the increase of the quantity of backwashing water, the application provides a treatment system for the electric desalting backwashing wastewater.

The application provides a processing system of electric desalination backwash waste water adopts following technical scheme:

along the flowing direction of the backwashing wastewater, the device comprises a demulsification unit, a coagulation unit, a flocculation unit and an air flotation unit which are sequentially communicated; the air supporting unit is communicated with a pulse air containing tank, the top of the pulse air containing tank is provided with a compressed air injection pipe and a clean water injection pipe, the bottom of the pulse air containing tank is provided with a water outlet pipe, and the water outlet pipe is communicated with the water inlet end of the air supporting unit.

By adopting the technical scheme, firstly, backwashing wastewater enters the demulsification unit, and the demulsifier is added into the demulsification unit, so that the interfacial tension of the emulsion can be changed, and colloidal particles in the backwashing wastewater lose stable repulsive force and attractive force and finally lose stability; backwashing wastewater from the demulsification unit enters a coagulation tank, and a coagulant is added into the coagulation unit at the moment, so that suspended solid can be destabilized to generate fine alum floc; backwashing wastewater containing fine alum flocs enters the flocculation unit from the coagulation unit, and at the moment, a flocculating agent is added into the flocculation unit, so that the fine alum flocs are gathered and enlarged, and the alum flocs are more uniform, firmer and denser; the play water of flocculation unit and the pulse hold the water that contains the saturated air in the outlet pipe of gas pitcher at last and mix in the air supporting unit, and at this moment, more closely knit alum blossom gathers together with the bubble, and the surface of air supporting unit is taken to alum blossom by the bubble, forms even scum layer, scrapes the scum layer, can be fine get rid of pollutants such as a large amount of dregs of fat, suspended solid and inorganic matter in the backwash waste water.

The application provides a new system comes independent processing backwash waste water, pollutant such as a large amount of dregs of fat, suspended solid and inorganic matter in the in-process of handling not only can be fine get rid of backwash waste water, and can not lead to backwash water volume to can not appear that the adjusting tank storage capacity is not enough, the mixed sewage of oil refinery is not enough to dilute backwash waste water or a large amount of backwash water volume causes a series of problems such as impact to sewage treatment plant's processing system.

Air is injected into the pulse air containing tank through the compressed air injection pipe, then is dissolved in water injected into the tank, and finally water containing saturated air is sent into the air floatation unit through the water outlet pipe, and bubbles released in the air floatation unit can be well attached to alum floc, and finally the alum floc is directly taken to the surface of the air floatation unit by the bubbles.

Preferably, an electromagnetic field unit is arranged at the upstream of the demulsification unit.

By adopting the technical scheme, the electric desalting backwashing wastewater firstly enters the electromagnetic field unit, the cluster structure of water molecules, organic pollutant molecules and ion atmosphere in the wastewater is changed through the electromagnetic field formed in the electromagnetic field unit, the physical, chemical, molecular mechanical and other properties of the backwashing wastewater are changed, the viscosity of effluent is reduced, charges are redistributed, the emulsification tendency and colloid stability of the backwashing wastewater are reduced, the using effect of the demulsifier, the coagulant and the flocculant is further improved, and the adding amount of the demulsifier, the coagulant and the flocculant is reduced. Meanwhile, the gas-phase molecule is dissolved, and the pulse gas dissolving effect is better.

Preferably, the electromagnetic field unit comprises an electromagnetic generator, a channel for backwash wastewater to pass through is arranged on the electromagnetic generator, and a water outlet end of the channel is communicated with a water inlet end of the demulsification unit.

By adopting the technical scheme, the electromagnetic field unit is simple in structure, convenient to operate and easy to implement.

Preferably, the pulse dissolved air unit comprises a pulse air tank, the top of the pulse air tank is provided with a compressed air injection pipe and a clean water injection pipe, the bottom of the pulse air tank is provided with a water outlet pipe, and the water outlet pipe is communicated with the water inlet end of the air flotation unit.

Preferably, the air flotation unit is communicated with a clear water outlet channel, and the clear water injection pipe is communicated with the clear water outlet channel through a reflux pump.

By adopting the technical scheme, water in the clear water outlet channel flows back to the pulse gas containing tank for cyclic utilization, so that water can be saved, and the treatment efficiency of backwashing wastewater can be improved to a certain extent.

The reflux pump is arranged to be beneficial to adjusting and accurately controlling the reflux quantity.

Preferably, the air flotation unit comprises an air flotation tank, a central guide cylinder is arranged in the air flotation tank, and the water outlet end of the flocculation unit is communicated with the bottom of the central guide cylinder.

Through adopting above-mentioned technical scheme, come from the backwash waste water that contains the alum flower in the flocculation unit and come from the water that contains saturated air in the pulse holds the gas pitcher and mix in the draft tube bottom, then flow from the draft tube top, this in-process, mud is deposited in air supporting bottom of the pool under self gravity, and the air bubble is fully contacted with alum flower and the air bubble takes off the alum flower to air supporting pond surface to be favorable to getting rid of the pollutant in the backwash waste water.

Preferably, a slag scraper and a slag collecting groove for collecting oil slag scraped by the slag scraper are arranged in the air floatation tank; and a mud scraper is arranged on the bottom wall of the air floatation tank.

Through adopting above-mentioned technical scheme, scrape being provided with of sediment machine and do benefit to and scrape into the album sediment inslot with superficial alum blossom, the oil residue etc. of air supporting pond surface to the pollutant in the backwash wastewater of better getting rid of improves the treatment effeciency of backwash wastewater. The sludge scraper can hang the sludge at the bottom of the air floatation tank into the sludge discharge port, and is favorable for removing the sludge at the bottom of the air floatation tank.

Preferably, the demulsification unit comprises a demulsification pool, the coagulation unit comprises a coagulation pool, the flocculation unit comprises a flocculation pool, and the demulsification pool, the coagulation pool and the flocculation pool are communicated in sequence.

By adopting the technical scheme, the demulsification unit, the coagulation unit and the flocculation unit are simple in structure and easy to implement.

Preferably, stirring devices are arranged in the breast breaking tank, the coagulation tank and the flocculation tank.

By adopting the technical scheme, the stirring device is favorable for fully mixing the demulsifier, the coagulant or the flocculant and water, thereby being favorable for improving the treatment efficiency of backwashing wastewater.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the application provides a new system for independently treating backwashing wastewater, so that a large amount of pollutants such as oil residues, suspended matters, inorganic matters and the like in the backwashing wastewater can be well removed in the treatment process, and the backwashing water quantity cannot be increased, so that a series of problems that the storage capacity of an adjusting tank is insufficient, the backwashing wastewater is not diluted by mixed sewage of an oil refinery, or the treatment system of a sewage treatment plant is impacted by a large amount of backwashing water quantity and the like cannot occur;

2. the electro-desalting backwashing wastewater firstly enters the electromagnetic field unit, the cluster structure of water molecules, organic pollutant molecules and ion atmosphere in the wastewater is changed through an electromagnetic field formed in the electromagnetic field unit, the viscosity of the effluent is reduced, the emulsification tendency and the colloid stability state of the backwashing wastewater are reduced, and the adding amount of a demulsifier, a coagulant and a flocculant can be reduced while the quality of the effluent is ensured.

Drawings

Fig. 1 is a schematic structural view of the entire structure.

Description of reference numerals: 1. a demulsification unit; 11. a breast breaking pool; 12. a demulsifier dosing unit; 2. a coagulation unit; 21. a coagulation tank; 22. a coagulant adding unit; 3. a flocculation unit; 31. a flocculation tank; 32. a flocculating agent dosing unit; 4. an air flotation unit; 41. an air floatation tank; 411. a central draft tube; 412. a clear water outlet channel; 413. a slag scraper; 414. a slag collecting groove; 415. a mud scraper; 416. a drive motor; 5. a pulse gas container; 51. a compressed air injection pipe; 52. a clean water injection pipe; 53. a water outlet pipe; 6. an electromagnetic field unit; 61. an electromagnetic generator; 7. a reflux pump; 8. a stirring device; 9. a sludge collection tank.

Detailed Description

Examples

The present application is described in further detail below with reference to fig. 1.

The embodiment of the application discloses a treatment system for electric desalting backwashing wastewater. Referring to fig. 1, along the flow direction of backwashing wastewater, the treatment system comprises an electromagnetic field unit 6, a demulsification unit 1, a coagulation unit 2, a flocculation unit 3 and an air flotation unit 4 which are communicated in sequence; the air flotation unit 4 is communicated with a pulse air containing tank 5, the top of the pulse air containing tank 5 is provided with a compressed air injection pipe 51 and a clear water injection pipe 52, the bottom of the pulse air containing tank 5 is provided with a water outlet pipe 53, and the water outlet pipe 53 is communicated with the water inlet end of the air flotation unit 4.

Referring to fig. 1, the electromagnetic field unit 6 includes an electromagnetic generator 61, a channel for backwash wastewater to pass through is provided on the electromagnetic generator 61, a water inlet end and a water outlet end are provided on the channel, the original backwash wastewater enters from the water inlet end of the channel, and the water outlet end of the channel is communicated with the water inlet end of the emulsion breaking unit 1.

Referring to fig. 1, the emulsion breaking unit 1 includes an emulsion breaking tank 11 and an emulsion breaker dosing unit 12; the coagulation unit 2 comprises a coagulation tank 21 and a coagulant dosing unit 22; the flocculation unit 3 comprises a flocculation tank 31 and a flocculating agent dosing unit 32; all install agitating unit 8 in broken breast pond 11, coagulating basin 21 and the flocculation basin 31, agitating unit 8 includes agitator motor, with agitator motor's output shaft's puddler, the rigid coupling has stirring vane on the puddler.

Referring to fig. 1, the air flotation unit 4 includes an air flotation tank 41, in this embodiment, the air flotation tank 41 is configured as a circular air flotation tank 41, an annular clean water outlet channel 412 is disposed in the circumferential direction of the air flotation tank 41, the clean water outlet channel 412 is connected to the clean water injection pipe 52 of the pulse gas container 5 through a return pump 7, a water inlet end of the return pump 7 is communicated with the clean water outlet channel 412, and a water outlet end is communicated with the clean water injection pipe 52. A central guide cylinder 411 is arranged in the middle of the air floatation tank 41, and a slag scraper 413 and a slag collecting groove 414 are arranged in the air floatation tank 41; the slag collecting groove 414 is located between the clean water outlet channel 412 and the central guide cylinder 411, and the inclined upper end of the bottom surface of the slag collecting groove 414 is close to the central guide cylinder 411, and the lower end is close to the clean water outlet channel 412. The slag scraper 413 scrapes the oil slag layer floating on the surface of the air floatation tank 41 into the slag collecting groove 414 by taking the central guide cylinder 411 as a circle center. The bottom of the air floatation tank 41 is set to be conical, a mud scraper 415 is installed at the bottom of the air floatation tank 41, an installation frame is arranged at the top of the central guide cylinder 411, a driving motor 416 is installed on the installation frame, and the driving motor 416 can drive the mud scraper 413 to move and can also drive the mud scraper 415 to move.

Referring to fig. 1, a sludge discharge port is formed at the bottom of the air flotation tank 41, a sludge collection tank 9 is arranged beside the air flotation tank 41, a first sludge discharge pipe is arranged between the sludge discharge port and the sludge collection tank 9, and a second sludge discharge pipe is arranged between the slag collection tank 414 and the sludge collection tank 9.

The application embodiment is an implementation principle of medium backwashing wastewater of a treatment system of electric desalting backwashing wastewater:

the original backwashing wastewater enters from the water inlet end of the electromagnetic generator 61, at the moment, the electromagnetic field formed in the electromagnetic generator 61 can change the cluster structure of water molecules, organic pollutant molecules and ion atmosphere in the wastewater, change the physical, chemical, molecular mechanical and other properties of the backwashing wastewater, redistribute charges, reduce the viscosity of the effluent, and reduce the emulsification tendency and colloid stability of the backwashing wastewater;

the backwashing wastewater with reduced viscosity is discharged from the water outlet end of the electromagnetic generator 61 and enters the emulsion breaking tank 11 from the water inlet pipe at the top of the emulsion breaking tank 11, at the moment, the emulsion breaker is added into the emulsion breaking tank 11 through the emulsion breaker dosing unit 12, and the emulsion breaker can change the interfacial tension of emulsion, so that the colloid particles in the backwashing wastewater lose stable repulsive force and attractive force and finally lose stability;

the water carrying the destabilized colloidal particles flows out from the bottom of the emulsion breaking tank 11 and flows into the coagulation tank 21 from the bottom of the coagulation tank 21, and at the moment, a coagulant is added into the coagulation tank 21 through a coagulant adding unit 22, the coagulant is fully mixed with backwashing wastewater, suspended solids are destabilized, and fine alum floc is generated;

the backwashing wastewater carrying the fine alum flocs overflows from the top of the coagulation tank 21 into the flocculation tank 31, and at the moment, a flocculating agent is added into the coagulation tank 21 through a flocculating agent adding unit 32, so that the flocculating agent is fully mixed with the backwashing wastewater containing the fine alum flocs, and the fine alum flocs are gathered and enlarged and are more uniform and more compact;

backwash wastewater with large and dense alum flocs flows out of the bottom of the flocculation tank 31, flows in from the bottom of the central guide cylinder 411 in the air floatation tank 41, is fully mixed with water containing saturated air from the pulse dissolved air tank, and can be well attached to the large and dense alum flocs, and finally the alum flocs are directly brought to the surface of the air floatation tank 41 by the bubbles; when a layer of oil residue or alum blossom is formed on the surface of the air floatation tank 41, the driving motor 416 is started, the driving motor 416 drives the slag scraping machine 413 to move, pollutants such as alum blossom, oil residue and the like floating on the surface of the air floatation tank 41 can be scraped into the slag collecting tank 414, and therefore a large amount of pollutants such as oil residue, suspended matters, inorganic matters and the like contained in backwashing wastewater can be well removed.

In this embodiment, the demulsifier, coagulant, and flocculant may be commercially available agents commonly used in sewage treatment.

Application example one

The electric desalting and backwashing wastewater of a certain oil refinery is in a black water emulsified state, and does not delaminate after long-time gravity precipitation. The existing oil separation and air flotation can not effectively treat oil and high suspended matters in the oil separation and air flotation.

The treatment system in the embodiment is used for treating the electric desalting backwashing wastewater of the oil refinery, and the treatment method comprises the following specific steps:

enabling the original electric desalting backwashing wastewater of the oil refinery to enter from the water inlet end of the electromagnetic reactor 61 and react for 5 s; then the mixture enters a demulsifying pool 11, 0.4ml/L of demulsifier is added into the demulsifying pool 11, and the reaction lasts for 1 min; then the mixture enters a coagulation tank 21, 200mg/L PAC coagulant is added into the coagulation tank 21, and the reaction is carried out for 3 min; then the wastewater enters a flocculation tank 31, 4mg/L of PAM flocculant is added into the flocculation tank 31 for reaction for 6min, then the flocculated water and circulating water saturated with micro-bubbles are mixed at the bottom of a central guide cylinder 411 of an air floatation tank 41, a reaction chamber is mixed for reaction for 20min, alum blossom and the micro-bubbles are gathered together, the formed alum blossom is supported to the surface of the air floatation tank by the micro-bubbles, a uniform scum layer is formed on the surface of the air floatation tank 41, and then the uniform scum layer is slowly scraped into a scum collecting tank 414 by a scum scraper 413.

In the above treatment process, the circulating water amount between the clear water outlet channel 412 and the pulse gas-containing tank 5 is 40% of the original backwash wastewater inlet amount, and the line pressure in the pulse gas-dissolving tank 5 is about 6 bar.

The quality of the clean water in the original backwash wastewater and clean water outlet channel 412 is detected, and the specific detection data are shown in the following table 1.

TABLE 1

Water sample	pH	SS(mg/L)	Total oil (mg/L)
				Original backwash wastewater	6-9	15000	2000
Clear water in clear water outlet channel	8.5	156	112

Application example two

The treatment system (except the electromagnetic generator 61) in the above embodiment is used for treating the electric desalting backwashing wastewater of the oil refinery, and the specific treatment is as follows:

enabling the original electric desalting backwashing wastewater of the oil refinery to enter a demulsification pool 11, adding a 0.6ml/L demulsifier into the demulsification pool 11, and reacting for 1 min; then the mixed solution enters a coagulation tank 21, 260mg/L PAC coagulant is added into the coagulation tank 21, and the reaction is carried out for 3 min; then the wastewater enters a flocculation tank 31, 5mg/L of PAM flocculant is added into the flocculation tank 31 for reaction for 5min, then the flocculated water and circulating water saturated with micro-bubbles are mixed at the bottom of a central guide cylinder 411 of an air floatation tank 41, a reaction chamber is mixed for reaction for 30min, alum blossom and the micro-bubbles are gathered together, the formed alum blossom is supported to the surface of the air floatation tank by the micro-bubbles, a uniform scum layer is formed on the surface of the air floatation tank 41, and then the uniform scum layer is slowly scraped into a scum collecting tank 414 by a scum scraper 413.

In the above treatment process, the circulating water amount between the clear water outlet channel 412 and the pulse dissolved air tank 5 is 40% of the original backwash wastewater inlet amount, and the line pressure in the pulse dissolved air tank 5 is about 6 bar.

The quality of the raw backwash wastewater and the clean water in the clean water outlet channel 42 are detected, and the specific detection data are shown in the following table 2.

TABLE 2

Water sample	pH	SS(mg/L)	Total oil (mg/L)
				Original backwash wastewater	6-9	15000	2000
Clear water in clear water outlet channel	8.4	163	116

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. A treatment system for electric desalting and backwashing wastewater is characterized in that: along the flowing direction of backwashing wastewater, the device comprises a demulsification unit (1), a coagulation unit (2), a flocculation unit (3) and an air flotation unit (4) which are communicated in sequence;

the air flotation unit (4) is communicated with a pulse air containing tank (5), the top of the pulse air containing tank (5) is provided with a compressed air injection pipe (51) and a clean water injection pipe (52), the bottom of the pulse air containing tank is provided with a water outlet pipe (53), and the water outlet pipe (53) is communicated with the water inlet end of the air flotation unit (4).

2. The system for treating electric desalting and backwashing wastewater as claimed in claim 1, wherein: an electromagnetic field unit (6) is arranged at the upstream of the demulsification unit (1).

3. The system for treating electric desalting and backwashing wastewater as claimed in claim 2, wherein: the electromagnetic field unit (6) comprises an electromagnetic generator (61), a channel for backwashing wastewater to pass through is arranged on the electromagnetic generator (61), and the water outlet end of the channel is communicated with the water inlet end of the demulsification unit (1).

4. The system for treating electric desalting and backwashing wastewater as claimed in claim 1, wherein: the air flotation unit (4) is communicated with a clean water outlet channel (412), and the clean water injection pipe (52) is communicated with the clean water outlet channel (412) through a return pump (7).

5. The system for treating electric desalting and backwashing wastewater as claimed in claim 1, wherein: the air flotation unit (4) comprises an air flotation tank (41), a central guide flow cylinder (411) is arranged in the air flotation tank (41), and the water outlet end of the flocculation unit (3) is communicated with the bottom of the central guide flow cylinder (411).

6. The system for treating electric desalting and backwashing wastewater as claimed in claim 5, wherein: a slag scraper (413) and a slag collecting groove (414) for collecting oil slag scraped by the slag scraper (413) are arranged in the air floatation tank (41); and a mud scraper (415) is arranged on the bottom wall of the air floatation tank (41).

7. The system for treating electric desalting and backwashing wastewater as claimed in claim 1, wherein: the demulsification unit (1) comprises a demulsification pool (11), the coagulation unit (2) comprises a coagulation pool (21), and the flocculation unit (3) comprises a flocculation pool (31); the breast breaking tank (11), the coagulation tank (21) and the flocculation tank (31) are communicated in sequence.

8. The system for treating electric desalting and backwashing wastewater as claimed in claim 7, wherein: stirring devices (8) are arranged in the breast breaking tank (11), the coagulation tank (21) and the flocculation tank (31).