JPS5850555B2 - Electrochemical purification device for contaminated liquids - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for the purification of liquids containing extraneous contaminants, and in particular to an apparatus for the electrochemical purification of liquids.

This invention can be used to purify liquids contaminated with organic substances, mechanical suspensions, surfactants, etc.

The present invention is particularly useful in the purification of fluids contaminated with oil and grease-containing wastewater produced in the production of petroleum products.

BACKGROUND ART Devices for electrochemical purification of liquids, particularly devices for purifying liquids by electrolevitation and electrocoagulation, have been widely used in recent years due to their high performance.

Known electrochemical liquid purification devices are classified into batch type and continuous type, with the latter device being considered more promising.

As a device for electrochemically purifying contaminated liquid, a settling chamber,
Devices are known which include an electrical coagulation chamber arranged coaxially with the settling chamber, a soluble electrode system, piping for purifying liquid discharge and means for removing foam from the device (e.g., U.S. Pat. No. 3,505,188). (see specification).

The means for removing foam from this apparatus is in the form of a rotatable scraper mounted on the top of the settling chamber, or in the form of a conveyor belt fitted with a plurality of paddles.

In such an apparatus, a part of the heavy components in the foam (free flocculants of the electrode metal hydroxide, contaminant particles, etc.) are thrown into the liquid in the settling chamber by a scraper.

If the settling chamber does not have sufficient height, the heavy components will be entrained in the liquid flow and carried into the purified liquid discharge pipe.

This has a negative impact on the efficiency of the purification promise.

USSR Inventor's Certificate No. 644378 describes an apparatus for the electrochemical purification of contaminated liquids, which is equipped with a sedimentation chamber, which is equipped with take-off pipes for the discharge of purified liquid and for the discharge of waste liquid, and which communicates with an electrocoagulation chamber.

The electrocoagulation chamber of this device is in the form of a tube with a system of soluble electrodes placed at its bottom.

The contaminated liquid is electrically introduced into the coagulation chamber through an inlet tube mounted above the electrode system.

This device is equipped with a foam remover in the form of a twisted pipe.

One end of this pipe, located above the electrocoagulation chamber, has an enlarged bell-shaped opening, and the other end of the pipe communicates with a pipe for draining waste liquid.

A drawback of this device is that some foam enters the upper part of the settling chamber through the space between the expansion opening and the electrocoagulation chamber.

Continuous operation of the device causes a considerable amount of foam to accumulate in the said parts of the device, with the result that a tight layer of foam is formed which gradually settles into the settling chamber.

It is therefore necessary to frequently clean the apparatus to remove the tight foam from the settling chamber, which considerably reduces the operating efficiency of the apparatus.

A device with a purification capacity of 6 m3 per hour requires 10 to 15 minutes of cleaning for 1.5 to 2 hours of operation.

A partial precipitate of broken, uncontaminated aggregates forms.

This coagulated precipitate is entrained in the flow of purified liquid and is carried into the take-off tube.

This has a negative impact on the quality and stability of the purification process.

Furthermore, the foam produced has a high thermodynamic stability and is stable for 3 to 5 hours.

Since the volume of foam is 5 to 10 times the volume of the contaminated liquid to be purified, a large-capacity container must be prepared to allow the foam to disappear naturally, or special means (mechanical, chemical, etc.) must be used to eliminate the foam. method) is required.

It is an object of the present invention to provide a foam remover configured to avoid foam compaction by continuously removing foam from the settling chamber, thereby increasing the stability of the purification process and the efficiency of the equipment. Another object of the present invention is to provide an electrochemical purification device for contaminated liquid, which reduces the operating cost of the device.

The object of the present invention is to provide (a) a sedimentation chamber equipped with a take-out pipe for separately discharging purified liquid and waste water, and (b) a sedimentation chamber disposed in communication with the sedimentation chamber and having a soluble electrode system at the bottom. an electrical coagulation chamber, (...) an intake pipe for introducing a contaminated liquid above the soluble electrode, an intake pipe for introducing an electrolyte, and (e) an enlarged opening at one end. In the electrochemical purification apparatus for contaminated liquid, the apparatus further comprises a remover for removing foam, the purification apparatus comprising a foam transport pipe for discharging foam from the settling chamber, the opening at the other end communicating with the discharge pipe. a foam transport tube is rotatable on a horizontal plane, the expanded opening at one end of the foam transport tube is disposed substantially above the settling chamber, and the foam transport tube has the expanded foam therein. This is achieved by an electrochemical purification device for contaminated liquids, characterized in that it is equipped with an air injector for transporting the suction foam through the opening and into the other end of the pipe.

With the device configured as described above, foam flowing into the settling chamber from the electrocoagulation chamber can be continuously removed from the settling chamber.

As a result, foam does not accumulate in the settling chamber.

Even the heavy components of the contaminant impurities are sucked into the enlarged opening and removed from the device.

The purification process is therefore more stable and there is no need for occasional cleaning of the equipment.

This is in sharp contrast to conventional equipment, which required cleaning to remove foam that accumulates in the settling chamber.

In order to improve the transport efficiency of the foam transport pipe for discharging foam from the settling chamber, it is advantageous to provide an insert in the form of a hydraulic screw in the foam transport pipe.

The installation of such an insert increases the friction between the foam and the transport pipe wall, causing the foam to separate into components such as oil, water, and air, thereby reducing the volume of the foam relative to the liquid to be removed. .

Furthermore, it is desirable to be able to control the amount of air supplied to the air injector in response to the foam level by locating a foam level controller with a sensor in the settling chamber and a final control element.

The provision of a foam level controller considerably reduces the power consumption required for foam removal.

This is because the air injector is activated only when sufficient foam has accumulated in the settling chamber.

Proper adjustment of the foam level controller will minimize the power consumption required for foam removal and maintain stability of the purification process.

The invention will now be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, the contaminated liquid purification apparatus has a cylindrical settling kiln 1, inside which a tubular electrical coagulation chamber 2 is coaxially formed.

Between the settling chamber 1 and the coagulation chamber 2 there is formed an annular settling zone defined by the walls of these chambers.

A take-out pipe 3 for discharging purified liquid is provided at the top of the sedimentation chamber 1, and a take-out pipe 4 for discharging waste liquid is provided at the lower part.

In order to increase the flow of purified liquid within the settling chamber 1, the annular settling zone is provided with a tubular partition 5.

In the upper part of the apparatus, an annular chute 6 bridging between the wall of the settling chamber 1 and the partition wall 5 is installed between the upper edge of the partition wall 5 and the electrical coagulation chamber 2.
It is located below the top of the .

A foam removal pipe 7 is provided above the chute 6.

A system 8 consisting of a plurality of soluble electrodes is provided in the lower part of the electrical coagulation chamber 2, some of these electrodes are connected to one terminal 9 of a DC power source (not shown), and the remaining electrodes are connected to one terminal 10. Connected.

An intake pipe 11 for introducing contaminated liquid is located above this electrode system.

A pipe 13 is provided in the central part of the device 12 for removing foam, which pipe 13 is attached to a pivot support 14 mounted on the cover 15 of the settling chamber 1.

The pivot support 14 is constructed in the same manner as before, and has an electric motor (
(not shown) to rotate the pivot horizontally.

The pivot support 14 includes a passage 16 for conveying compressed air to an air injector 19 attached to the pipe 13;
I have 17 and 18.

The pipe 13 has an enlarged opening 20 above the settling chamber 1 and an open end bent above the annular chute 6.

The position of the air injector 19 and the position of the enlarged opening 20 have a predetermined mutual relationship, and when compressed air is sent to the air injector 19, foam is sucked into the enlarged opening 20 and directed inside the pipe 13 toward its open end. It is designed to be transported by

FIG. 2 shows another embodiment of the present invention, in which the partition wall 5 is slightly shorter and the upper part thereof, together with the annular chute 6, constitutes a flange having an L-shaped cross section.

Inlet pipe 2 is used to supply electrolyte into electrical coagulation chamber 2.
1 is provided below the soluble electrode system 8.

Additionally, to make foam removal more efficient by reducing the foam volume in the foam condensate, as shown in FIG.
An insert member 22 in the form of a hydraulic screw is inserted into the pipe 13.
It can also be installed inside.

As shown in FIG. 3, a foam level control device may be installed to reduce the power consumption required for foam removal.

This control device consists of a foam level controller 23, a sensor 24 mounted in the settling chamber 1 and final control elements such as a solenoid valve 25 connected to a line 26 delivering compressed air to the air injector 19.

Hereinafter, a method of operating the apparatus according to the present invention will be explained.

Prior to introducing the contaminated liquid, a pure electrolyte (industrial water with a small amount of HCl and Na (J' additive)) is added.
is filled into the electrical coagulation chamber and the electrode system 8 is activated.

After a certain period of time (25-30 seconds), contaminated liquid is introduced into the device through the intake tube 11.

The contaminated liquid fills the electrocoagulation chamber 2.

During the process of anodic dissolution of the soluble electrode, metal hydroxides are formed, which float together with gas bubbles (hydrogen and oxygen).

The metal hydroxide is contained in the liquid. Colloidal contaminants are coagulated into aggregates.

Furthermore, these agglomerates are carried upwards through the electrocoagulation chamber by gas bubbles.

The liquid treated as described above moves together with the aggregates to the settling vehicle 1, where it is separated into oil, foam and pure liquid layers in the settling chamber.

Under the action of the air jet, the foam is sucked into the pipe 13.

In the process of passing through the pipe 13, the foam is separated into oil and water, falls onto the chute 6, and further flows into the exhaust pressure pipe 7 from there.

That is, as the pipe 13 rotates, it sucks the foam from the settling chamber into its enlarged opening 20.

The air jet emitted from the injector 19 dissipates the foam and reduces its volume.

The valuable condensate is then settled in a separate vessel.

The purified liquid is discharged from the discharge pipe 3 and the sludge accumulated in the settling chamber 1 is discharged from the discharge pipe 4.

When the insert 22 (see FIG. 2) is installed in the pipe 13, the foam is caused to rotate within the pipe 13.

The friction between the foam and the inner wall of the pipe 13 and the screw surface of the insertion member 22 enhances the action of eliminating the foam and separating oil and water, and the oil and water efficiently fall onto the annular chute 6 as described above.

The defoaming product is transferred to another container and subjected to settling.

The device according to the invention includes a foam level controller 23 (see Figure 3).
can be placed.

When the foam level in the settling chamber 1 reaches a predetermined limit, the sensor 24 of the foam level controller 23 is activated, and the pulp means 2
5 works to send compressed air to the air injector 19 from a compressed air source (not shown).

When the foam level in the settling chamber 1 falls below a predetermined limit, a signal sent from the sensor 24 to the foam level controller 23 disconnects the compressed air source from the air injector 19.

As a result of operating the device according to the present invention, the operational reliability is very high, and the labor consumption for maintaining the device is on average 8.
It was found that the reduction was between 10% and 10%.

No special maintenance is required to remove foam from this device.

By placing a screw-shaped charge in the pipe, the defoaming efficiency is significantly improved, the foam content volume in the condensate is reduced by a factor of 15 to 20, and the volume ratio of foam to liquid condensate is reduced. It is 0.15 or less.

There is therefore no need for further treatment of the foam condensate.

By providing a foam level controller in the housing, the power consumption required for foam removal is significantly reduced.

1600 to 3200 mg/
As a result of purifying the old cutting fluid containing 1.5 liters of impurities, the amount of compressed air consumed was reduced by 2.7 to 3.0 times.

Although the present invention has been described above in terms of preferred embodiments, those skilled in the art will readily understand that various modifications can be made to the invention without departing from the scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one example of the electrochemical purification device for contaminated liquid according to the present invention, and FIG. 2 is a cross-sectional view (showing a part of the device) showing a modified aspect of the device according to the present invention. FIG. 3 shows yet another modification of the device according to the present invention (
FIG. Reference numbers are as follows. 1... Sedimentation chamber, 2...
...Electrical pseudolysis chamber, 3...Takeout pipe for discharging purified liquid, 4...Takeout pipe for discharging waste liquid, 8...
... Soluble electrode system, 11 ... Intake pipe for supplying contaminated liquid, 12 ... Foam remover, 13 ...
Foam transport pipe, 19...Air injector, 20
Enlarged opening, 21...Intake pipe for electrolyte supply,
22...Insert member, 23...Foam level controller, 24...Sensor.

Claims (1)

[Claims] 1. (a) A sedimentation chamber equipped with a take-out pipe for separately discharging purified liquid and waste water, (b) A sedimentation chamber disposed in communication with the sedimentation chamber and having a soluble electrode system at the bottom. (c) an intake pipe for introducing the contaminated liquid above the soluble electrode; (d) an intake pipe for introducing the electrolyte; and (e) an enlarged opening at one end. and a remover for removing foam from the purification device, comprising a foam transport tube for discharging foam from a settling chamber, the opening at the other end communicating with a discharge tube, The foam transport pipe is rotatable on a horizontal plane, the enlarged opening at one end of the foam transport pipe is disposed substantially above the settling chamber, and the foam transport pipe carries the foam therein. 1. An electrochemical purification device for contaminated liquid, characterized in that it comprises an air injector for transporting suction foam through a suction pipe from an enlarged opening to the other end of the pipe. 2. Device according to claim 1, in which the foam transport pipe for discharging foam from the settling chamber has an insert in the form of a hydraulic screw. 3. Claims 1 or 2, comprising a foam level controller with a sensor in the settling chamber and a final control element, making it possible to control the amount of air supplied to the air injector in response to the foam level. The device described.