KR101466371B1 - Electrolyzer for producing high concentration NaOCl - Google Patents

Abstract

The present invention seeks to provide an electrolytic apparatus capable of producing a high concentration of sodium hypochlorite. The electrolytic apparatus of the present invention includes a plurality of electrolytic baths (10) and connecting ports (11a, 12a) connecting both ends of the electrolytic bath and arranged in parallel as in the vertical direction. The electrolytic bath (10) comprises a cylindrical inner tube (22) having open ends at both ends, and a cylindrical outer tube (26) surrounding the inner tube, the anode current being applied to the outer tube A current of a negative electrode is applied to the tube so that the surface area of the anode is formed larger than the surface area of the cathode.

Description

{Electrolyzer for producing high concentration NaOCl} for producing high concentration sodium hypochlorite [

TECHNICAL FIELD The present invention relates to a seawater electrolytic apparatus, and more particularly, to a seawater electrolytic apparatus configured to produce sodium hypochlorite at a high concentration.

Generally, an electrolytic device refers to a metal recovery or water treatment facility using electrolysis to produce sodium hypochlorite (NaOCl) by electrolyzing a solution containing seawater, brine or electrolytes. Electrolysis equipment that generates sodium hypochlorite mainly electrolyzes seawater to produce industrial sodium hypochlorite and injects it into the cooling system of large plant such as power plant, steel plant or petrochemical to prevent growth and attachment of shellfish and microorganism And is used for the purpose of.

Electrolytic plants are designed to generate sodium hypochlorite by electrolysis of sodium chloride (NaCl) contained in seawater or salt water by applying DC power to both the anode and the cathode. This electrolytic reaction can be represented by the main reaction and the side reaction, and the reactions at the anode and cathode are as follows.

[Main reaction]

- Anode reaction: 2Cl → Cl ₂ + 3e ^-

- anode ^{reaction: 2Na + 2e - → 2Na +} + 2H 2 O → 2NaOH + H 2

- Total reaction: Cl ₂ + ₂ NaOH → NaOCl + NaCl + H ₂ O

[Side reaction]

- anode: 6ClO ^- + 3H ₂ O ^- > 2ClO ₃ ^- + 4Cl ^- + 6H ⁺ + 3 / 2O ₂ + 6 ^e-

2H ₂ O - > O ₂ + 4H ⁺ + 4e _-

- Cathode: ClO ^- + H ₂ O + 2e ^- → Cl ^- + 2OH ^-

_{2NaOH + MgCl 2 → Mg (OH} ) 2 + NaCl

_{2NaOH + CaCl 2 → Ca (OH} ) 2 + NaCl

As can be seen from the above reaction formula, sodium hypochlorite (NaOCl) is produced at the anode, while magnesium oxide and calcium hydroxide are produced at the side reaction of the cathode. It is well known that magnesium oxide and calcium hydroxide produced in the negative electrode adhere to the electrode and grow in scale as described above, so that the efficiency of the electrolytic device is substantially lowered. In order to remove such a scale, there is a need to periodically stop the operation and perform cleaning using acid.

Electrolytic equipment for generating sodium hypochlorite by using the electrolytic reaction can be divided into a plate type and a tube type. Currently, plate type is widely applied to plants such as power plants or steel mills. Currently, the seawater electrolytic apparatus currently used only produces sodium hypochlorite at a low concentration (1,500 to 2,000 ppm). In the case of using a plate-type electrolytic apparatus having a low flow rate, generation and growth of the above- And it is difficult to generate sodium hypochlorite at a high concentration at the same time. If the apparatus is operated to generate a high concentration of sodium hypochlorite by using the existing equipment, excessive generation and growth of the excess of the temperature and the scale, and deterioration of the operation efficiency due to the excessive generation of the scale are disadvantageous.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is a main object of the present invention to provide an electrolytic apparatus capable of producing sodium hypochlorite at a high concentration.

Another object of the present invention is to provide an electrolytic apparatus which is light in weight and small in volume as a whole.

It is still another object of the present invention to provide an electrolytic device capable of reducing the amount of power consumption and suppressing scale generation as much as possible in order to achieve high efficiency of electrolytic performance.

An electrolytic cell according to the present invention comprises a cylindrical inner tube having openings at both ends thereof and a cylindrical outer tube surrounding the inner tube, wherein a current of a positive polarity is applied to the outer tube, The surface area of the anode is larger than the surface area of the cathode, and the electrolysis reaction of the seawater flowing therebetween is caused.

An electrolytic bath according to an embodiment of the present invention includes a cylindrical inner tube having openings at both ends and a cylindrical outer tube surrounding the inner tube, and the outer tube and the inner tube are each provided with an anode A single current is applied and the surface area of the applied positive electrode is larger than the surface area of the negative electrode and the electrolytic reaction of the seawater flowing therebetween is caused.

According to another embodiment, the apparatus further comprises a cylindrical intermediate tube inserted between the inner tube and the outer tube. For example, the surface area of the anode of the outer tube is 2 to 12 times larger than the surface area of the cathode of the inner tube, and the surface area of the anode of the outer tube is 2.5 to 3.5 times larger than the surface area of the cathode of the inner tube desirable.

According to the present invention, the surface area of the cathode or anode applied to the inner tube or the outer tube is adjustable by surface coating of the tube.

According to another embodiment of the present invention, the apparatus further comprises a cooling jacket installed to surround the outer tube and having an inlet through which cooling water flows and an outlet through which heat-exchanged cooling water is discharged.

The electrolytic apparatus of the present invention comprises a cylindrical inner tube having open ends at both ends thereof and a cylindrical outer tube surrounding the inner tube, wherein a current of a positive polarity is applied to the outer tube, A plurality of electrolytic cells to which a current is applied so that the surface area of the anode is larger than the surface area of the cathode and are arranged in parallel; And a curved connecting member for sequentially connecting both ends of the electrolytic bath.

The electrolytic apparatus according to another embodiment further includes a plurality of cooling jackets installed to surround the outer tubes of the plurality of electrolytic cells and through which the cooling water circulates, and the cooling jackets sequentially pass through the plurality of cooling jackets .

According to yet another embodiment, the apparatus further comprises a cylindrical intermediate tube inserted between the inner tube and the outer tube.

In the electrolytic apparatus according to another embodiment, the electrolytic bath located on the upstream side among the plurality of electrolytic baths is formed so that the ratio of the surface area of the anode to the cathode is higher than that of the electrolytic bath located on the downstream side.

In the electrolytic apparatus according to another embodiment, the electrolytic bath located on the upstream side among the plurality of electrolytic baths, as compared with the electrolytic bath located in the middle portion, and the electrolytic bath located in the middle portion, The ratio of the surface area of the negative electrode is higher.

According to the present invention, an effective electrolytic reaction can be performed by controlling the surface area, and it can be seen that sodium hypochlorite at a high concentration can be produced using only seawater. The ability to produce such a high concentration of sodium hypochlorite as described above means that the flow rate can be substantially increased and the power consumption can be reduced substantially.

Therefore, by increasing the flow rate relatively, generation of scale can be suppressed as much as possible, and suppression of generation of such a scale can be sufficiently understood in the basic configuration of the present invention, which substantially minimizes the surface of the negative electrode. The generation of sodium hypochlorite at a high concentration can achieve miniaturization of the storage tank of sodium hypochlorite produced. The suppression of scale formation and such miniaturization means that the electrolytic apparatus can be downsized substantially as a whole, which means that it is possible to provide an electrolytic apparatus having a small volume at the same time as being lightweight even in a place where space restriction is followed.

The ability to generate a high concentration of sodium hypochlorite can also have the advantage of being capable of shock dosing as well as continuous dosing in facilities such as power plants that require it.

1 is a front view of an electrolytic apparatus according to the present invention.
FIG. 2A is an exploded perspective view of an electrolytic bath according to the present invention. FIG.
FIG. 2B is a perspective view of the assembled state of the electrolytic bath according to the present invention. FIG.
3 is a partially cutaway perspective view of an electrolytic apparatus of the present invention.

Hereinafter, the present invention will be described in more detail based on the embodiments shown in the drawings.

First, as shown in FIG. 1, an electrolytic apparatus according to the present invention includes a plurality of tubular electrolytic baths 10. The electrolytic bath 10 is composed of multiple stages over the upper and lower portions. In the illustrated embodiment, the electrolytic baths at the same height are composed of a pair of front and rear. It is a matter of course that the plurality of electrolytic cells are connected in parallel, which is advantageous in terms of space efficiency. In the illustrated embodiment, a plurality of electrolytic cells are connected in parallel in the vertical direction and a pair is connected in parallel in the forward and backward directions.

For example, the electrolytic bath 11 positioned at the bottom is also located on the front surface shown in the drawing, and is formed of a pair located on the rear surface not shown in the figure. Therefore, the cylindrical electrolytic bath 10 according to the present invention comprises at least one electrolytic bath 11, 12 located at the lower part, at least one electrolytic bath 13, 14 at the middle part, and at least one electrolytic bath 13, And the electrolytic baths 15, 16, and 17.

Each of the electrolytic baths 10 is sequentially connected to the upper electrolytic bath or the rear electrolytic bath by the curved or semicircular connecting ports 11a and 12a which are not orthogonal to each other so that the flow rate can be maintained at a desired level have. Here, the connection means that the seawater is connected to each electrolytic cell so that the electrolytic reaction can be generated in the electrolytic cell sequentially.

The connecting ports 11a and 12a and the respective electrolytic baths 10 are connected to each other by the flange connecting portions 11b and 12b so that the sea water flowing into the electrolytic bath 11 at the lower end portion, 14, 15, 16, 17 in the upper portion of the car, and the electrolytic reaction is caused by flowing through the electrolytic bath 12 and the electrolytic bath 13, 14, 15, 16, When the plurality of electrolytic baths are arranged in the upper and lower parts or in parallel as described above, it is preferable to provide the support frame F for supporting the respective electrolytic baths. In the illustrated embodiment, the support frame F is vertically and horizontally And is configured to support a plurality of arranged electrolytic baths 10, respectively.

Next, an internal configuration of each electrolyzer 10 will be described based on FIG. 2 and FIG. 3A to 3C show the construction of the electrolyzer according to the present invention. FIG. 3A shows the electrolytic baths 11 and 12 in the lower part, FIG. 3B shows the electrolytic baths 13 and 14 in the middle part, The electrolytic bath of the electrolytic baths 15, 16, and 17 of FIG.

FIG. 2A is a perspective view of an electrolytic cell in an exploded view, and will be referred to with reference to FIG. The electrolytic bath of the present invention comprises an inner tube (22) and an outer tube (26) installed to surround the outer portion of the inner tube (22). An intermediate tube (24) is provided between the inner tube (22) and the outer tube (26). Each of the tubes 22, 24, and 26 is formed in a cylindrical shape having concentric circles, and both ends are open so that the seawater can flow in and out.

As described above, both ends of the electrolytic bath 10 including the inner tube 22, the intermediate tube 24 and the outer tube 26 are connected to the connecting ports 11a and 11b by the flange connecting portions 11b and 12b, 12a. A first connector 42 and a second connector 44 for electrically connecting the inner tube 22 and the outer tube 26 are provided between the electrolyzer 10 and the connectors 11a and 12a. An insulation flange 46 for insulation is provided between the first connector 42 and the second connector 44. Between each of the flange-shaped connectors 42 and 44 and the insulation flange 46, Gaskets (Ga, Gb, Gc) for preventing leakage are installed.

3, the first connector 42 and the second connector 44 are connected to the inner tube 22 and the outer tube 26 selectively by positive (+) or negative (-) poles to be installed. For example, a cathode may be applied to the inner tube 22 through the first connector 42 and an anode may be applied to the outer tube 26 through the second connector 44. It is needless to say that the application of the electric current from the connectors 42 and 44 to the inner tube 22 and the outer tube 24 can be performed in other configurations than those shown in FIG. 3, seawater for causing the electrolytic reaction is supplied between the inner tube 22 and the outer tube 26, and the inner tube 22 is provided with a stopper member 29, for example, So that it is prevented from flowing.

According to the embodiment shown in FIG. 3, a negative (-) pole is applied to the inner tube 22 and a positive pole is applied to the outer tube 26. With this configuration, it can be seen that the surface area of the outer tube 26 to which the anode is applied is relatively larger than the surface area of the inner tube 22 to which the cathode is applied.

As can be seen from the above electrolytic reaction, the maximum value of the effective chlorine can be said to be related to the competition between the main reaction of the anode and the side reaction of the cathode, so that the main reaction of the anode is more efficient, The present invention is conceived in that it has a close relationship with that of reducing the size of the image.

That is, in order to obtain a high concentration of sodium hypochlorite, it is possible to consider using a highly efficient anode capable of obtaining a high concentration and reducing the decomposition at the cathode. Here, by reducing the surface area of the cathode So that the reaction occurs small. Since the reaction at the cathode can be said to be related to the product of the scale as shown in the above-mentioned reaction formula, it is preferable to suppress the reaction at the cathode.

In consideration of this point, in this embodiment, the cathode is applied to the inner tube 22 and the anode is applied to the outer tube 26 as described above. In the present embodiment in which the intermediate tube 24 is provided between the inner tube 22 and the outer tube 26, when current is applied while the seawater flows between the inner tube 22 and the outer tube 26 , The inner surface of the outer tube 26 will have a positive electrode and thus the outer surface of the middle tube 24 will have a negative electrode. And the outer surface of the inner tube 22 will have a negative electrode and the outer surface of the middle tube 24 will have a positive electrode.

The sea water flowing between the inner tube 22, the intermediate tube 24, and the outer tube 26 having such a polarity causes the electrolytic reaction as described above. According to the present invention, as described above, the surface area of the portion of the anode is larger than the surface area of the anode. According to the embodiment, the anode is applied to the outer tube and the cathode is applied to the inner tube, thereby ensuring a wider surface area of the anode. However, even if the anode is not applied to the outer tube as in the present embodiment, it is possible to adjust the surface area so as to wrap the positive electrode and the negative electrode by not polarizing by coating the outer tube or a part of the inner tube surface Do.

As can be seen from the experiment, the efficiency of the electrolytic reaction can be increased if the ratio of the anode to the cathode is more than 2 times as much as the surface area of the anode to the cathode. If the surface area of the anode is increased to 12 times The efficiency of electrolytic reaction was high. Here, according to the experiment of the inventor of the present invention, when an anode is applied to the outer tube 26 and the cathode is applied to the inner tube 22, It was found that sufficient electrolytic reaction occurred at the surface area of

By adjusting the surface area as described above, the ability to increase the efficiency of the electrolysis reaction means that substantially high sodium hypochlorite can be produced. For example, when the ratio of the positive electrode to the negative electrode is 1: 1 as in the conventional plate type electrolytic apparatus, or when the surface area of the positive electrode is less than that of the negative electrode as in the tubular type electrolytic apparatus, Only sodium chlorate could be produced.

However, as described above, when the surface area of the anode is made larger than that of the cathode, it is possible to produce sodium hypochlorite at a high concentration of 4,000 ppm or more. In the case of efficient operation, sodium hypochlorite at a high concentration of 8,000 to 10,000 ppm or more can be produced Could know.

Hereinafter, a cooling apparatus according to the present invention will be described. It can be said that it is preferable to sufficiently cool the electrolytic bath 10 even when sodium hypochlorite at a high concentration is produced according to the present invention. 1 and 3, a cooling jacket 40 for water cooling is installed in each of the electrolytic baths 10 so as to surround the electrolytic bath 10. The cooling jacket 40 of the uppermost electrolytic bath 17 is provided with an inlet 42 through which water can be input and an outlet is formed at a lower portion of the cooling jacket 40 opposite the cooling jacket 40. The outlet may serve as an inlet for supplying water to the lower electrolytic bath 16, and may be referred to as a connection portion 44.

An outlet 46 is formed in the lower part of the electrolytic bath 11 at the lowermost end. The cooling water discharged through the outlet 46 is a relatively high temperature because each electrolytic bath is cooled. The cooling water discharged through the outlet 46 may be configured to be discharged to the outside or circulated back to the water tank. That is, in the case of cooling using seawater, it is preferable that the cooling water introduced through the inlet 42 is heated while passing through the plurality of electrolytic baths, and the cooling water having passed through the final electrolytic bath is discharged to the outside through the outlet 46. In the case of using the separate cooling water, the cooling water coming out of the outlet 46 should be returned to the separate cooling water tank, and then the temperature should be lowered by the heat exchange and then circulated through the above-mentioned path.

In the embodiment shown in FIG. 1, it is understood that the plurality of electrolytic baths 10 are composed of a plurality of layers. Here, the electrolytic bath 11 at the lowermost end is the portion into which the initial seawater is input, and the electrolytic bath 17 at the uppermost end is the last electrolytic bath in which the electrolytic reaction is completed.

As described above, the main object of the present invention is to produce a high concentration of sodium hypochlorite by increasing the surface area of the anode to be larger than the surface area of the cathode, for example, 2 to 12 times as described above. In this case, the electrolytic bath on the upstream side of the plurality of electrolytic baths 10, that is, the electrolytic bath at the lowermost end into which the sea water is inputted can be referred to as the upstream side when viewed in the flow of seawater. For example, It can be said that the electrolytic bath of the side. On the contrary, the electrolytic baths 15, 16, and 17 positioned at the upper side are electrolytic baths on the downstream side.

In the present invention, in order to produce sodium hypochlorite at a high concentration, it is also possible to design the surface area of the anode to be larger than the surface area of the cathode in the entire electrolytic bath 10 as described above. In another embodiment, the electrolytic baths on the downstream side of the electrolytic baths 11 and 12, for example, the electrolytic baths 15, 16 and 17, It can be said that it is also effective to form a larger size.

For example, the area ratio of the anode to the cathode in the downstream electrolytic bath 11 and 12 is set to 2: 1, the area ratio of the anode to the cathode of the electrolytic bath 13, 14 in the middle is 2.5: 1, The area ratio of the positive electrode to the negative electrode of the electrolytic baths 15, 16, 17 of the electrolytic cell 1 can be sufficiently made to be 3: 1. By doing so, the concentration of sodium hypochlorite will become higher toward the downstream electrolytic bath due to the electrolytic reaction occurring while passing through the plurality of electrolytic baths, and ultimately it is possible to produce sodium hypochlorite with a high concentration of about 8,000 to 10,000 ppm .

In this embodiment, each of the plurality of electrolytic cells can easily be replaced by having a desired surface area, so that maintenance for more efficient electrolytic reaction can be facilitated. In addition, as described above, it is possible to easily adjust the surface area of the anode and the cathode by preventing synthetic resin coating on the surface of the inner tube and the outer tube of the electrolytic bath so as not to be polarized.

The ability to produce such a high concentration of sodium hypochlorite can be expected to have several advantages in the following respects.

According to the present invention, it is possible to produce sodium hypochlorite at a high concentration only by using seawater, that is, without addition of salt. The fact that the production of sodium hypochlorite at a high concentration by the more efficient electrolytic reaction is possible also means that the flow rate of seawater flowing in the electrolytic cell can be increased relatively, that is, compared to the conventional one. The fact that the flow rate in the electrolytic apparatus is high means that substantially the adhesion and growth of the scale can be suppressed as much as possible. This can also be understood in terms of minimizing the surface area of the cathode and minimizing the scale generated in the reaction of the cathode.

The high-efficiency electrolysis system can be said to induce a more efficient electrolysis reaction as compared with the actual amount of input power, so that it is possible to substantially reduce the power consumption. It is needless to say that the temperature rise due to the high efficiency can be sufficiently prevented by using the cooling jacket in which the cooling water according to the present invention circulates.

According to the present invention, since sodium hypochlorite at a high concentration is produced as a result, it becomes possible to minimize the size of a storage tank of sodium hypochlorite produced, thereby minimizing the overall volume of the electrolytic apparatus It will be understood enough. This can be advantageous for a marine platform that is subject to a lot of installation space.

As described above, according to the present invention, it is possible to induce a more efficient electrolytic reaction by increasing the surface area of the anode compared to the surface area of the cathode. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

10, 11, 12, 13, 14, 15, 16, 17 ..... electrolyzer
22 ..... inner tube
24 ..... intermediate tube
26 ..... outer tube
40 ..... cooling jacket
42, 44 ..... Connector

Claims (12)

delete delete delete delete delete delete delete And a cylindrical outer tube surrounding the inner tube, wherein a current of a positive polarity is applied to the outer tube, and a current of a negative polarity is applied to the inner tube, A plurality of electrolytic baths formed larger than the surface area of the cathodes and arranged in parallel;
And a curved connector for sequentially connecting both ends of the electrolytic bath;
Wherein an electrolytic cell located on an upstream side among a plurality of electrolytic cells has a higher ratio of a surface area of a positive electrode to a negative electrode than an electrolytic cell located on a downstream side.
And a cylindrical outer tube surrounding the inner tube, wherein a current of a positive polarity is applied to the outer tube, and a current of a negative polarity is applied to the inner tube, A plurality of electrolytic baths formed larger than the surface area of the cathodes and arranged in parallel;
And a curved connector for sequentially connecting both ends of the electrolytic bath;
The ratio of the surface area of the anode to the surface of the anode is higher than that of the electrolytic bath located on the upstream side among the electrolytic baths located on the upstream side and the electrolytic bath located on the downstream side of the electrolytic bath located in the middle part Electrolytic device. The electrolytic apparatus according to claim 8 or 9, further comprising a cylindrical intermediate tube inserted between the inner tube and the outer tube. The cooling apparatus according to claim 8 or 9, further comprising: a plurality of cooling jackets installed to surround the outer tubes of the plurality of electrolytic cells and through which the cooling water circulates, wherein cooling water is sequentially passed through the plurality of cooling jackets An electrolytic device. delete

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