KR100711438B1 - A method for removing floating matter and chlorine contained in a gas-cleaning facility of iron-making process and an apparatus - Google Patents

Abstract

The present invention relates to a method for improving the cooling water quality of a gas cleaning facility for washing gas discharged with dust in a steel making process with water, and an apparatus applied thereto, to precipitate and remove suspended matter in the form of oxides by supplying ozone and electrolysis. The purpose of the present invention is to remove chlorine ions contained in the cooling water, thereby to smooth the flow of cooling water in the gas cleaning equipment and to prevent corrosion of the gas cleaning equipment.

The present invention for achieving the above object,

Providing a condensation tank in a cooling water line providing a flow path of the cooling water passing through the steelmaking gas cleaning equipment; supplying the suspended solids and the chlorine-containing cooling water through the steelmaking gas cleaning equipment to the condensing tank through the cooling water line; Supplying ozone to the condensation tank to which the water is supplied, oxidizing the suspended matter contained in the cooling water to precipitate it in the form of an oxide; removing the precipitated oxide as described above; and removing the suspended chlorine ion-containing cooling water therein. The positive electrode plate and the negative electrode plate are supplied to an electrodialysis device provided with an ion permeable membrane interposed therebetween to gasify chlorine ions contained in the cooling water in the positive electrode plate by electrolysis. Supplying the cooling water introduced into the electrode plate to the gas cleaning equipment; gasified chlorine gas as described above Separating the chlorine gas from the cooling water by sending the containing cooling water to the gas-liquid separator; and supplying the chlorine gas separated from the cooling water to the chlorine gas remover containing the sodium hydroxide solution, reacting with the aqueous sodium hydroxide solution to precipitate and remove the chlorine gas. And, the chlorine gas is separated from the cooling water is discharged from the gas-liquid separator and supplied to the electrodialysis, characterized in that for removing the suspended solids and chlorine contained in the cooling water of the gas cleaning equipment, and the apparatus used therein, It is a technical point.

Steelmaking gas cleaning equipment, cooling water, chlorine, electrolysis

Description

Method for removing suspended solids and chlorine contained in the cooling water of the steelmaking gas cleaning equipment and the apparatus used for the same {A METHOD FOR REMOVING FLOATING             

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing a preferred example of a float and chlorine removal apparatus which is preferably applied to a method for removing suspended matter and chlorine contained in cooling water according to the present invention.

Figure 2 is a side view showing a preferred example of the condensation tank preferably applied to the method for removing the suspended matter contained in the cooling water according to the present invention.

3 is a plan view showing a preferred example of a condensation tank preferably applied to a method for removing suspended solids contained in cooling water according to the present invention.

Figure 4 is a side view showing a preferred example of the electrodialysis machine which is preferably applied to the method for removing chlorine ions contained in the cooling water according to the present invention.

5 is an example of a gas-liquid separator showing a preferred example of a gas-liquid separator which is preferably applied to a method for removing chlorine ions contained in cooling water according to the present invention.

6 is an example of a chlorine gas removal device showing a preferred example of a chlorine gas remover preferably applied to a method for removing chlorine ions contained in cooling water according to the present invention.

Figure 7 is a schematic diagram of a float and chlorine removal device is added to the float and chlorine removal device of Figure 1;

* Explanation of symbols for main parts of drawing *

One… Gas cleaning facility

2… Condensing tank, 21... Channel, 22... Support 23. Electrode plate, 23 (a)... (+) Electrode plate, 23 (b)... Negative electrode plate, 24.. wire

3... Ozone generator, 31... Ozone Supply Nozzle

4… Sedimentation tank

5... Electrodialysis machine, 51... Ion permeable membrane, 52 (a)... (+) Electrode plate, 52 (b)... (-) Electrode plate, 53. Entrance, 54... exit

6... Gas-liquid separator, 61... Entrance, 62... Gas outlet, 63... Cooling water outlet

7... Vacuum pump

8… Chlorine degasser, 81... Gas inlet, 82... Sodium hydroxide solution inlet, 83.. Glass beads, 84... Sodium hydroxide solution, 85... Separator

9... Pump

10... Reservoir

The present invention relates to a method for improving the cooling water quality of a gas cleaning facility for washing gas discharged with dust in a steel making process with water, and an apparatus applied thereto, and more particularly, a floating material contained in the cooling water from the gas cleaning facility. A method and apparatus for removing chlorine.

Normally, the steelmaking equipment is provided with a gas cleaning equipment for washing the dust discharged with the gas with cooling water, and the cooling water contained in the gas cleaning equipment is used in a repeated circulation. However, when the coolant is used repeatedly, suspended matter in the coolant increases, which may stick to the surface of the facility or the pipes, disrupt the flow of the coolant, and cause corrosion of the facility. In addition, chlorine ions accumulate in the cooling water and the concentration increases to a level that can cause corrosion of the gas cleaning equipment. That is, about 800 ppm of chlorine ion exists in the cooling water used once, but if the cooling water is repeatedly used without removing the chlorine ion in the cooling water, the concentration of chlorine ion is the concentration that can cause corrosion of the gas cleaning equipment. Will increase to more than 2000ppm. As such, when the corrosion of the facility is caused by the cooling water, the gas leaks out, which may cause a big obstacle in the operation of the steel making facility, and various techniques have been developed in the past to prevent this. For example, a method of precipitating chlorine ions by adding sodium sulfite disclosed in Korean Patent Publication No. 95-8377, a method of adsorbing ionic components using coke powder or activated carbon disclosed in Japanese Patent Application Laid-Open No. 10-249170, US Patent No. 6096179 The electrolysis method using the composite carbon electrode disclosed in the above, the method of filtering using a fine filter, etc. are mentioned.

However, when chemicals are used, sediment treatment becomes a problem, and when the filter is used, the pores of the filter are easily blocked by various particles.

In addition, in the case of using the adsorption method with coke or activated carbon, the efficiency of chlorine ion adsorption is low and needs to be replaced frequently. In the case of the electrolysis method using a composite carbon electrode, calcium or magnesium is attached to the electrode, resulting in electrolysis efficiency. There is a problem of this deterioration.

Accordingly, the present inventors have repeatedly conducted research and experiments to solve the above problems, and propose the present invention based on the results. The present invention supplies ozone to precipitate and remove suspended matter in the form of oxides, and electrolysis. The purpose of the present invention is to remove chlorine ions contained in the cooling water, thereby to smooth the flow of cooling water in the gas cleaning equipment and to prevent corrosion of the gas cleaning equipment.

The present invention for achieving the above object,

Providing a condensation tank in a cooling water line providing a flow path of cooling water passing through the steelmaking gas cleaning facility;

Supplying the suspended solids and the chlorine-containing cooling water from the first gas cleaning facility to the condensation tank through the cooling water line;                     

Supplying ozone to a condensation tank to which the cooling water is supplied, oxidizing the suspended matter contained in the cooling water to precipitate in the form of an oxide; and

The present invention relates to a method for removing suspended solids contained in cooling water for a gas making facility of a steelmaking plant comprising the step of removing the precipitated oxide as described above.

In addition, the present invention,

Cooling water containing chlorine ions or cooling water containing chlorine ions with suspended solids as described above is supplied to an electrodialysis device provided with an (+) electrode plate and a (-) electrode plate with an ion permeable membrane interposed therebetween, so that the (+) electrode Gasifying chlorine ions contained in the cooling water in the plate, and supplying the cooling water introduced into the negative electrode plate inside the electrodialysis machine to a gas cleaning facility;

Sending the gasified chlorine gas-containing cooling water as described above to the gas-liquid separator to separate the chlorine gas from the cooling water; And

As described above, the chlorine gas separated from the cooling water is supplied to a chlorine gas remover containing an aqueous solution of sodium hydroxide to react with the aqueous sodium hydroxide solution for precipitation and removal. The present invention relates to a method for removing chlorine contained in cooling water of a gas making facility for a steelmaking plant, and the apparatus used therein.

In addition, the present invention,

Providing a condensation tank in a cooling water line providing a flow path of cooling water passing through the steelmaking gas cleaning facility;

Supplying the suspended solids and the chlorine-containing cooling water from the first gas cleaning facility to the condensation tank through the cooling water line;

Supplying ozone to the condensation tank to which the cooling water is supplied to oxidize the suspended matter contained in the cooling water to precipitate in the form of an oxide;

Removing the precipitated oxide as above;

As described above, the chlorine ion-containing cooling water from which the suspended solids are removed is supplied to the electrodialysis device provided with the (+) electrode plate and the (-) electrode plate interposed therebetween and contained in the cooling water at the (+) electrode plate by electrolysis. Gasifying the prepared chlorine ions, and supplying the cooling water introduced into the negative electrode plate in the electrodialysis machine back to the gas cleaning facility;

Sending gasified chlorine gas-containing cooling water to the gas-liquid separator to separate chlorine gas from the cooling water; and

As described above, the chlorine gas separated from the cooling water is supplied to a chlorine gas remover containing an aqueous solution of sodium hydroxide to react with the aqueous sodium hydroxide solution for precipitation and removal. The present invention relates to a method for removing suspended solids and chlorine contained in cooling water of a gas making facility of a steelmaking plant, and the apparatus used therein.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated with reference to drawings.

Figure 1 is a schematic diagram showing a preferred example of the suspended solids and chlorine removal apparatus in the cooling water according to the present invention.

That is, FIG. 1 shows the apparatus for removing the suspended matter and chlorine contained in the cooling water using a preferred example of the apparatus for removing the suspended matter in the cooling water of the present invention and a preferred example of the apparatus for removing the chlorine in the cooling water.

First, a method of removing impurities contained in cooling water according to the present invention will be described with reference to FIG. 1.

In order to remove the suspended matter in the cooling water according to the present invention, as shown in FIG. 1, the condensate tank 2 is connected to the cooling water line 102 through the cooling water line 102 through which the cooling water passing through the first gas cleaning facility 1 provides a flow path of the cooling water. To be supplied.

The ozone generator 3 is attached to the condensation tank 2 so that ozone is supplied therein, and the suspended solids contained in the cooling water from the gas cleaning facility 1 are supplied in the form of oxide, for example, Ca It is oxidized with (OH) ₂ , Mg (OH) ₂ , CaCO ₃ , CaSO ₄ , and the like.

The suspended matter in the form of oxide in the condensation tank (2) is precipitated in the settling tank (4) and then removed.

Preferable examples of the condensation tank 2 are shown in Figs. 2 and 3, Fig. 2 is a side view and Fig. 3 is a plan view.

2 and 3, the condensation tank 2 is preferably provided with an ozone supply nozzle 31 connected to the ozone generator.

The ozone supply nozzle 31 is preferably formed of a porous so that bubbles can easily occur.

The ozone by the ozone supplied through the supply nozzles 31, as well as the suspended matter contained in the water is oxidized chlorine ions, chlorate ions primary (ClO ^-), chlorite ion (ClO ^2-), chlorate ion (ClO ^3- ) And perchlorate ions (ClO ^4- ). They can decompose again and oxidize many suspended matters by supplying oxygen ions (O ⁻ ) with high energy.

In addition, it is preferable to provide the condensation tank 2 with a plurality of electrode plates 23 supported by a support 22 that is a non-conductor. As shown in FIG. 3, the plurality of electrode plates 23 may be disposed such that the positive electrode 23a and the negative electrode 23b intersect with each other. The electrode plate 23 serves to entangle the suspended particles in each other, the number is preferably set in proportion to the flow rate, installed at intervals of 3 ~ 4cm to match the flow direction of the cooling water flowing along the channel 21 It is desirable to. The reason is that when the distance between the electrode plates is greater than 4 cm, the electromotive force between the plates becomes weak and the suspended particles do not entangle with each other.                     

When the ozone supply nozzle 31 is provided as described above, the ozone supply nozzle 31 is preferably disposed between the plurality of electrode plates 23.

In FIG. 3, the code | symbol 24 represents an electric wire.

Next, a method of removing chlorine from chlorine ion-containing cooling water will be described.

In order to remove chlorine from the chlorine ion-containing cooling water according to the present invention, as shown in FIG. 1, the chlorine ion-containing cooling water is supplied to the gas-liquid separator 6, and then, as shown in FIG. 4 by the pump 9. The positive electrode plate 52 (a) and the negative electrode plate 52 (b) are supplied to the electrodialysis machine 5 provided with the ion permeable membrane 51 interposed therebetween, In the electrode plate 52 (a), the chlorine ions contained in the cooling water are gasified, and the gasified chlorine gas-containing cooling water is sent to the gas-liquid separator 6 to separate the chlorine gas from the cooling water.

Of course, the chlorine ion-containing cooling water can be directly supplied to the electrodialysis machine 5 without passing through the gas-liquid separator 6.

On the other hand, if the suspended solids are removed in the cooling water in advance by using the suspended solids removing apparatus of the present invention as described above, when the chlorine ion-containing cooling water is electrolyzed in the electrodialysis machine, the ion permeable membrane is not blocked due to the suspended solids. Decomposition can proceed smoothly.

As the (+) electrode plate 52a and the (-) electrode plate 52b, a plate in which ruthenium oxide (RuO ₂ ) is plated on a titanium plate is preferable, and any one can be used as long as it has excellent Cl ⁻ trapping ability. .

In addition, as the ion permeable membrane 51, any one of fine pores, preferably pores having a diameter of 3 to 5 mm and a durable polymer material can be used. Polymeric materials can be used.

Cooling water containing chlorine gas (Cl ₂ ) generated in the (+) electrode plate 52a is discharged through the upper outlet 54 of the electrodialysis machine, as shown in FIGS. 1 and 5, the gas-liquid separator 6. Supply to the inlet (61) of. The gas-liquid separator 6 serves to separate the chlorine gas from the cooling water. The gas-liquid separator 6 preferably has a spherical shape in order to withstand the vacuum well, and the inside has a weak vacuum, preferably an internal absolute pressure of 0.7 to 0.9. It is desirable to keep atm.

Next, the chlorine gas separated in the gas-liquid separator 6 is discharged through the discharge port 62 and sent to the chlorine gas remover 8, between the gas-liquid separator 6 and the chlorine gas remover 8 to facilitate this. It is preferable to install the vacuum pump 7 in the chamber.

In addition, the cooling water from which the chlorine gas is separated and discharged is discharged through the discharge port 63 and sent back to the electrodialysis machine 5.

This cooling water may contain ungasified chlorine ions.                     

In this way, the cooling water sent to the gas-liquid separator 6 is supplied to the inside of the electrodialysis machine 5 again through the inlet 53 of the electrodialysis machine together with the cooling water replenished from the settling tank 4.

Meanwhile, some of the cooling water supplied to the inlet 53 of the electrodialysis machine 5, that is, the cooling water containing calcium, magnesium, and the like, which are cations, pass through the ion permeable membrane 51 to form a negative electrode plate 52b. As shown in Figure 1, it is discharged through the outlet 54 of the electrodialysis machine 5 as shown in Figure 1 is supplied back to the gas cleaning equipment (1).

As described above, the chlorine gas sent to the chlorine gas remover 8 is removed by reacting with sodium hydroxide to form a precipitate in the form of NaCl.

As shown in FIG. 6, the chlorine gas remover 8 has a separator plate 85 having a hole therebetween, the upper portion of which is filled with glass beads 83, and about 2 of the lower portion, preferably the lower portion. / 3 is preferably configured to be filled with sodium hydroxide solution 84.

The chlorine gas remover 8 is provided with a gas inlet 81.

The sodium hydroxide solution is sprayed onto the glass beads 83 through a solution supply part 82 provided at the upper portion of the chlorine gas remover 8 by a pump 9 to contact chlorine gas to generate NaCl precipitate.

It is preferable that the said sodium hydroxide aqueous solution mixed 20-40 weight part of solid NaOH with respect to 100 weight part of water.

In the above, a method of removing the suspended matter and chlorine contained in the cooling water by using a preferred example of the apparatus for removing the suspended matter in the cooling water and the preferred example of the apparatus for removing the chlorine in the cooling water has been described. Of course, it is possible to remove the suspended matter in the coolant using only the suspended matter removal device in the cooling water or to remove the chlorine using only the chlorine removal device in the cooling water.

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLE

This embodiment was done using the apparatus of FIG.

The apparatus of FIG. 7 has the same configuration as the apparatus of FIG. 1 except for replacing the gas cleaning system 1 with the reservoir 10.

After collecting 10 liters of the cooling water of the actual process, it was supplied to the reservoir 7 and the cooling water was recycled at a flow rate of 2 liters / minute.

The apparatus was made of acrylic, the electrode 52 used an electrode of 100 cm ² , the electrolytic current was adjusted to 26 A, and the corresponding electrolytic voltage was 7.4 V.

Thereafter, the concentration of chlorine ions in the cooling water collected in the storage tank 10 was measured, and the results are shown in Table 1 below.

Minutes Chlorine concentration (ppm) 0 5660 2 2140 4 1450 6 1190 8 800

As shown in Table 1, as a result of experiments using the suspended solids and chlorine ion removal device of the present invention, over time, the concentration of chlorine in the cooling water decreases, which may cause corrosion of the steelmaking gas cleaning equipment, which is 2000 ppm or less. It can be seen that the decrease.

Moreover, after a long time, it was confirmed that no chlorine ion deposit was attached to the electrode or the ion permeable membrane.

As described above, according to the present invention, ozone can be used to more effectively remove suspended matters contained in cooling water, and chlorine ions contained in cooling water can be removed by simple electrolysis, which is very convenient for management. The operating cost is inexpensive.

Claims (6)

Providing a condensation tank (2) in a cooling water line providing a flow path of cooling water passing through the first gas cleaning facility (1); Supplying the suspended solids and the chlorine-containing cooling water that have passed through the first gas cleaning facility (1) to the condensation tank (2) through the cooling water line; Supplying ozone to the condensation tank (2) to which the cooling water is supplied to oxidize the suspended matter contained in the cooling water to precipitate in the form of an oxide; Removing the precipitated oxide as above; As described above, the chlorine ion-containing cooling water from which suspended matter is removed is supplied to the electrodialysis machine 5 provided with the positive electrode plate 52a and the negative electrode plate 52b interposed therebetween. By the electrolysis to gasify the chlorine ions contained in the cooling water in the (+) electrode plate (52a), and the cooling water entering the (-) electrode plate (52b) inside the electrodialysis machine 5 is a gas cleaning equipment (1). Feeding back); Sending the gasified chlorine gas-containing cooling water to the gas-liquid separator 6 to separate chlorine gas from the cooling water; and As described above, the chlorine gas separated from the cooling water is supplied to the chlorine gas remover (8) containing the aqueous sodium hydroxide solution, reacted with the aqueous sodium hydroxide solution, precipitated and removed, and the cooling water from which the chlorine gas is separated from the gas-liquid separator (6). Method for removing suspended solids and chlorine contained in the cooling water of the steelmaking gas cleaning equipment characterized in that it comprises the step of discharging and supplying back to the electrodialysis machine (5). The method of claim 1, wherein the pressure inside the gas-liquid separator 6 is in a vacuum state lower than atmospheric pressure. The method for removing suspended solids and chlorine contained in cooling water of a gas making facility according to claim 1 or 2, characterized in that the absolute pressure inside the gas-liquid separator 6 is 0.7 to 0.9 atm. A condensation tank (2) to which an ozone generator (4) is attached, to which ozone is supplied, and which oxidizes the suspended matter contained in the cooling water from the gas cleaning facility (1) by the supplied ozone in an oxide form; A settling tank (3) for precipitating suspended matter in an oxide form in the condensing tank (2); The positive electrode plate 52a is interposed between the ion permeable membrane 51 so as to electrolyze the chlorine ion-containing cooling water from which the precipitate in the sedimentation tank 3 is removed to gasify the chlorine ions contained in the cooling water with chlorine gas. An electrodialysis machine 5 provided with a negative electrode plate 52b; A gas-liquid separator (6) for separating chlorine gas from cooling water containing chlorine gas gasified in the electrodialysis machine (5); And Apparatus for removing suspended solids and chlorine contained in the cooling water of the gas purification equipment of the steelmaking plant comprising a chlorine gas remover (8) for reacting the chlorine gas discharged from the gas-liquid separator (6) with an aqueous sodium hydroxide solution to precipitate and remove the chlorine gas. 5. The condensation tank 2 has a shape in which a plurality of electrode plates 23 are supported by the support 22, and the plurality of electrode plates 23 is connected to the (+) electrode plate 23a. Apparatus for removing suspended solids and chlorine contained in the cooling water of the steelmaking gas cleaning equipment, characterized in that the (-) electrode plates 23b are arranged to intersect. The apparatus of claim 4 or 5, wherein an ozone supply nozzle 31 is installed between the plurality of electrode plates 23.

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