JP5705761B2 - Seawater electrolysis chlorine injection system - Google Patents

Description

  The present invention relates to a seawater electrolysis type chlorine injection device for removing scale in a chlorine injection pipe.

  Conventionally, in a power plant constructed on the coast, seawater is used as cooling water for a power generation system, and seawater is introduced into the power plant as cooling seawater from a water inlet using a seawater introduction pipe. In a seawater intake system that takes in seawater, chlorine is injected into the seawater introduction pipe with chlorine water using seawater electrolysis or the like as a countermeasure against attached organisms in the seawater.

  The seawater electrolysis chlorine injection device is installed adjacent to the power plant, and chlorine is generated from seawater in the seawater electrolysis tank. The chlorine water in which this chlorine is dissolved is an intake pipe for introducing seawater into the power plant. Is introduced into the water conduit by an injection nozzle or the like.

  By the way, since the scale which has magnesium hydroxide, calcium carbonate, etc. which are contained in seawater as a main component produces | generates on the electrode surface of a seawater electrolysis apparatus, the flow rate ensuring of an electrode surface and periodic electrode cleaning are performed. For this reason, the chlorine water contains alkali components such as magnesium hydroxide precipitated in the seawater electrolysis apparatus, and dissolves while flowing in the chlorine piping, increasing the pH of the chlorine water. There's a problem.

  If the piping length is long and the residence time is long in the chlorine piping, when a certain threshold pH is exceeded, calcium carbonate precipitates from the chlorine water and a strong scale containing other suspended components such as sand in the chlorine water. In the pipe. As this scaling progresses, the chlorine injection pipe may be blocked.

  When chlorine water cannot be injected into cooled seawater, marine organisms adhere to the plant seawater system and seawater intake becomes impossible, leading to plant shutdown. Therefore, it is important to prevent scale in the chlorine piping.

  Therefore, the present inventors have prevented the inflow of alkaline components such as magnesium hydroxide from the electrolytic apparatus into the piping, adjusted the pH of the chlorine water, reduced the residence time in the piping by securing the flow velocity in the piping, and washed out the precipitates. A method for preventing scale in chlorine piping such as was previously proposed (Patent Document 1).

JP 2006-231199 A

According to the proposal of Patent Document 1, for example, the method for removing the scale is more difficult than the existing system because the facility is larger than the existing system.
In addition, the method of adjusting the pH of the bulk of chlorine water or increasing the flow rate is adopted, but even if the pH of the bulk is adjusted or the flow rate is increased, the pipe bend or complicated shape where solid magnesium hydroxide is deposited There is a problem that the generation of the scale continues gently in the part, and it is difficult to completely prevent the scaling.

  As a result, there is a problem that after the operation for a long period of time, the scale grows or the peeled scale is clogged, so that stable injection of chlorine water cannot be performed.

  Therefore, when supplying chlorine water from the electrolyzer, a method for removing the scale generated in the chlorine injection pipe and a method for further reducing the scale generation are desired.

  This invention makes it a subject to provide the seawater electrolysis-type chlorine injection apparatus which aims at the removal of the scale in chlorine injection piping in view of the said problem.

  1st invention of this invention for solving the subject mentioned above is a seawater electrolysis type chlorine injection device which throws chlorine water into seawater when seawater is used as cooling water supplied to a power plant, When chlorine water supplied from the seawater electrolysis device of the seawater electrolysis chlorine injection device introduces chlorine water to the vicinity of the intake of the power plant, and when there is a sign of a decrease in the supply rate of the chlorine injection piping, the chlorine injection The seawater electrolysis chlorine injecting apparatus includes an acid cleaning means for cleaning the pipe with acid cleaning water and an acid waste liquid storage tank for storing the acid cleaning waste liquid.

The second invention according to the first invention, the chlorine injection pipe toward the intake, are found provided gradually inclined, by a predetermined distance from the distal end side of the chlorine injection pipe, and a plurality of valves closed A space is formed, an acid injection line is provided in the vicinity of the low-side valve in the closed space, the acid cleaning water is introduced into the closed space, and the inside is cleaned, and the closed space is inclined. In the seawater electrolysis chlorine injection device, a waste liquid line is provided in the vicinity of the valve on the higher side, and the acid cleaning waste liquid is discharged.

The third invention is the first invention, the chlorine injection pipe, consecutively disposed, et al are along the crest of the land or the seabed and valleys, closing the valley between the chlorine injection pipe with valve The closed space is formed, an acid injection line is provided in the valley, the acid wash water is introduced into the closed space from the valley side, the inside is cleaned, and a waste liquid line is provided in the peak. The seawater electrolysis chlorine injecting apparatus is characterized in that the acid cleaning waste liquid is discharged.

  A fourth invention is a seawater electrolysis chlorine injecting device for introducing chlorine water into the seawater when using seawater as cooling water supplied to the power plant, wherein the seawater is introduced into the power plant from the water inlet A chlorine injection pipe that extends into the seawater introduction pipe and is supplied from the seawater electrolysis apparatus of the seawater electrolysis chlorine injection apparatus to the vicinity of the water intake, and a supply rate of the chlorine injection pipe Seawater electrolytic chlorine injection, characterized by comprising an acid cleaning means for cleaning with acid cleaning water from the tip side of the chlorine injection pipe when there is a sign of a drop, and an acid waste liquid storage tank for storing acid cleaning waste liquid In the device.

  According to the present invention, in the chlorine injection pipe for supplying the chlorine water to the seawater introduction pipe, when there is a sign of a decrease in the supply rate of the chlorine water, the chlorine injection pipe is washed with the acid cleaning water. It is possible to prevent obstruction due to the scale.

FIG. 1 is a schematic view of a seawater electrolysis chlorine injection device according to the present embodiment. FIG. 2 is a schematic view when the chlorine injection pipe is gradually inclined toward the intake port of the seawater introduction pipe. FIG. 3 is another schematic diagram when the chlorine injection pipe is gradually inclined toward the intake port of the seawater introduction pipe. FIG. 4A is a diagram illustrating an example in which a chlorine injection pipe is disposed in the seawater introduction pipe. FIG. 4-2 is a diagram illustrating an example in which a chlorine injection pipe is disposed in the seawater introduction pipe. FIG. 5 is a diagram illustrating an example of installing a chlorine injection pipe in a land portion.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by this Example, Moreover, when there exist multiple Example, what comprises combining each Example is also included. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

A seawater electrolysis chlorine injection device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of a seawater electrolysis chlorine injection device according to the present embodiment.
As shown in FIG. 1, the seawater electrolysis chlorine injection device 10 according to the present embodiment uses a seawater electrolysis type in which chlorine water 13 is introduced into the seawater 12 when seawater 12 is used as cooling water supplied to the power plant 11. The chlorine injection device 10 includes a chlorine injection pipe 16 for introducing the chlorine water 13 supplied from the seawater electrolysis device 14 of the seawater electrolysis chlorine injection device 10 to the vicinity of the water intake 15 of the power plant 11, and the chlorine injection pipe 16. What has an acid tank 18 that is an acid cleaning means for cleaning the chlorine injection pipe 16 with the acid cleaning water 17 and an acid waste liquid storage tank 20 for storing the acid cleaning waste liquid 19 when there is a sign of a decrease in the supply rate It is.
The seawater 12 supplied to the seawater electrolysis apparatus 14 is supplied from the power plant 11 side, but the present invention is not limited to this.

In this embodiment, in order to prevent the organisms in the seawater conduit 11a taking the seawater 12 from adhering, the chlorine water 13 generated in the seawater electrolysis device 14 is supplied from the water intake 15 side of the tip by the chlorine injection pipe 16. Supplying inside.
In the present invention, in order to prevent clogging of the chlorine injection pipe 16 that supplies the chlorine water 13, the occurrence of deposits such as calcium carbonate and magnesium hydroxide is predicted in the pipe, and the deposits are treated with a strong acid (for example, hydrochloric acid). The acid cleaning water 17 is used for efficient cleaning.

Here, the sign of the occurrence of deposits in the chlorine injection pipe 16 is confirmed by the blockage of the chlorine injection pipe 16 (for example, an increase in pump discharge pressure, a decrease in flow rate by a flow meter, a change in sound or vibration, light The turbidity changes by the transmission method, etc.).
In addition, a test piece for monitoring made of the same material as that of the chlorine injection pipe 16 is prepared separately, and the condition of introducing the chlorine water 13 from the seawater electrolysis apparatus 14 is simulated to check the state of scale generation. Also good.

  For example, in the confirmation by the current meter, when there is a decrease of about 10% in the design flow rate, it is determined that there is a sign of scale generation, and cleaning with the acid cleaning water 17 is performed.

Further, in the case of a test piece, ranking may be performed according to the amount of scale generation as a guideline for scale generation, and it may be determined that there is a sign of scale generation when the reference rank is reached.
In addition, when checking by light transmission method (for example, infrared inspection), if far infrared inspection sensors are installed at multiple locations in the pipe and the light transmission level reaches the standard rank, there is a sign of scale generation. Judgment should be made.

In the present embodiment, a chemical solution capable of dissolving the deposits in the pipe mainly composed of a mixture of calcium carbonate, magnesium hydroxide, sand, algae, plankton, organic matter, etc. is supplied from the tip side of the chlorine injection pipe 16. Yes. As this chemical solution, acid cleaning water 17 is used. For example, the acid cleaning water 17 is supplied from the acid tank 18 provided in the floating body 31 floating on the sea by the pump P ₁ through the acid injection line L ₁ . .

Further, after washing the inside of the chlorine injection pipe 16 with an acid washing water 17, the cleaning line L ₂ for blowing the waste or residue in the tube in sea water 12, and joins the acid injection line L _1. By this blow operation, the acid cleaning water 17 remaining in the chlorine injection pipe 16 is removed. This blow operation pump P ₂ is installed in the floating body 31 and supplies seawater to the acid injection line L ₁ via the cleaning line L ₂ . The pump P ₂ may be installed together with the floating body 31 on the acid tank 18 side.

Thereby, it is prevented that the acid cleaning water 17 and the residue in the piping are brought into the power plant 11.
In this blow operation, for example, the turbidity of blow water can be measured with a turbidimeter to determine the end of blow. In addition, you may make it perform chemical analysis evaluation of the underwater component suspension density | concentration also by visual evaluation.
The blow water may be discharged into the seawater if there is no problem with the quality of the cooling water 12 of the power plant 11.

The acid waste liquid at the time of pipe cleaning by this acid washing operation and blow operation and the washed seawater waste liquid after washing are stored in an acid waste liquid storage tank 20 provided on land of the power plant 11 via a waste liquid line L ₃ .
The waste liquid in the acid waste liquid storage tank 20 is processed in a separate processing facility.

In addition, during acid cleaning, calcium carbonate, which is a type of scale, dissolves while generating carbon dioxide with a strong acid, so an inclination is made in advance so that the gas (carbon dioxide) generated during dissolution of the scale can be discharged. And discharged to the outside from the waste liquid line L ₃ .

In the present embodiment, the acid tank 18 has been described as being permanently installed on the floating body 31 floating on the sea. However, the present invention is not limited to this, and the acid tank 18 and the pump are connected from the port during the scale removal operation. The floating body 31 or the like provided with P ₁ and P ₂ may be towed to a position above the water inlet 15, and the acid injection line L ₁ may be connected to the distal end side of the chlorine injection pipe 16 by, for example, a diver.

  The state of blockage in the chlorine injection pipe 16 is monitored by a monitoring device, and the cleaning operation in the chlorine injection pipe 16 is performed when it falls below or falls below a preset threshold value.

  As a threshold value for this cleaning, for example, an amount of chlorine water for which a required chlorine injection amount per unit time cannot be secured can be exemplified.

Here, the scale removal by the acid cleaning water 17 will be described.
When the acid cleaning water 17 is introduced into the chlorine injection pipe 16, calcium carbonate as a scale dissolves while generating carbon dioxide with a strong acid (see the following formula (1)). Using this dissolving action, the inside of the scale in the chlorine injection pipe 16 is cleaned and removed.
CaCO ₃ + 2HCl → CaCl ₂ + CO ₂ ↑ + H ₂ O (1)

  In the present invention, a strong acid is used as the acid cleaning water 17 and the presence / absence of gas generation is used as an index, thereby confirming scale dissolution (completion of cleaning) in the pipe that does not know where it is and suppressing excessive acid injection. be able to.

  By adopting a chemical treatment method using a strong acid as the acid cleaning water 17, the pipe length is long (1 km or more) unlike a physical method using a brush or the like, and the scale is deposited anywhere in the pipe. This is advantageous when it is difficult to determine whether it is present.

Examples of the acid cleaning water 17 include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid. However, nitric acid and phosphoric acid need to be treated with nitrogen and phosphorus in the waste water. Can not.
In the case of using hydrochloric acid, chlorine ions in hydrochloric acid are components that are primarily contained in seawater, and the waste liquid can be discharged only by pH adjustment (for example, 5 to 9).

  When sulfuric acid is used, exothermic or sparingly soluble calcium sulfate may be generated. Therefore, sulfuric acid is not used alone, but is preferably used as an auxiliary agent for enhancing acidity.

  As the acid concentration, an 11% to 35% hydrochloric acid solution or a mixture of hydrochloric acid and sulfuric acid is used.

Examples of means for detecting the generation of gas generated during scale cleaning include blowing, balloons, anemometers, and anemometers.
It is also possible to use a CO ₂ measuring detector for measuring the CO ₂ concentration in the gas.
Further, as a method for determining the end point of cleaning, the pH of the discharged water may be measured except for gas detection.

  By adopting a piping material and accessories having good acid resistance in advance as the chlorine injection pipe 16 and accessories in the system, it is possible to use a high concentration acid as a chemical solution. Thereby, the cleaning time can be shortened and the waste liquid treatment tank volume can be reduced. As a result, the load on the existing waste liquid treatment facility can be reduced.

  Examples of the chlorine injection pipe 16 having good acid resistance and chemical resistance include pipes using resin materials such as hard vinyl chloride and polyethylene.

Conventionally, when a pipe is blocked, the pipe must be replaced. However, providing a cleaning facility can extend the life of the pipe.
When the chlorine injection pipe is blocked by the scale and the chlorine injection becomes difficult, it can be restored in a short time, and the cooling water (seawater) 12 can be stably supplied to the plant 11.
By using a high-concentration acid, it is easy to determine the end of washing, the amount of acid used can be reduced, and the scale can be dissolved reliably.
In addition, the amount of drainage to be processed can be reduced.

  Even if scale deposits in the chlorine injection pipe 16 and it becomes difficult to inject the chlorine water 13 into the seawater conduit 11a, the chlorine injection can be continued by taking the measures of this embodiment. .

  As described above, according to this embodiment, in the chlorine injection pipe 16 that supplies the chlorine water 13 to the seawater introduction pipe 11a, when there is a sign of a decrease in the supply rate of the chlorine water 13, the inside of the chlorine injection pipe 16 is By washing with the acid wash water 17, blockage of the chlorine injection pipe 16 due to the scale can be prevented in advance, and the power plant 11 can be cooled stably.

A seawater electrolysis chlorine injection device according to an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same member as the structure of the seawater electrolysis-type chlorine injection apparatus of FIG. 1, and the description is abbreviate | omitted.
FIG. 2 is a schematic view when the chlorine injection pipe is gradually inclined toward the intake port of the seawater introduction pipe.
In the seawater electrolysis chlorine injection device 10 according to the present embodiment shown in FIG. 2, the chlorine injection pipe 16 is gradually inclined toward the intake port 15 of the seawater introduction pipe 11a at the sea bottom X.

When the chlorine injection pipe 16 is gradually inclined as described above, the first valve V ₁ and the second valve V ₂ on the water intake 15 side are closed, and the acid cleaning water 17 is introduced from the acid injection line L _1. The acid cleaning water 17 is introduced from the lower side into the closed space between the first valve V ₁ and the second valve V _{2 in the} vicinity of the acid injection line L _1, and the waste liquid is provided in the vicinity of the upper second valve V _2. and discharging the waste liquid and gas from the line L _3. Thereafter, a blow operation is performed to wash the residue.

Then, the third valve V ₃ and the fourth valve V ₄ is closed, the third valve V ₃ near the acid injection line L ₁ from the acid washing water 17 is introduced, third valve V ₃ and the fourth valve V ₄ The acid cleaning water 17 is introduced from the lower side into the closed space, and the cleaning operation is performed in the same manner as the first.
This operation is sequentially performed upward from the water inlet 15 side, and the cleaning operation in the chlorine injection pipe 16 is completed.
In addition, what is necessary is just to change suitably the installation of a closed space and a valve according to the installation condition of the scale in the chlorine injection piping 16. FIG.

  As described above, by inclining the chlorine injection pipe 16 toward the water intake 15 in advance at the sea bottom X, the gas generated during the cleaning can be efficiently discharged and the backflow of the generated gas can be prevented.

  Here, since the acid cleaning water 17 used for cleaning is the volume of the chlorine injection pipe 16, for example, the pipe diameter is 8 inches and the length is 1.5 km, although it depends on the pipe diameter and installation length. In some cases, about 18.5 t is required for one washing.

FIG. 3 is another schematic diagram when the chlorine injection pipe is gradually inclined toward the intake port of the seawater introduction pipe.
As shown in FIG. 3, a chlorine injection pipe 16A and a bypass chlorine injection pipe 16B are provided, and chlorine water 13 is bypassed by the bypass chlorine injection pipe 16B so that chlorine injection is not stopped even during cleaning of the main chlorine injection pipe 16A. It is possible to inject.
Also, the bypass chlorine injection pipe 16B can be similarly cleaned with a chemical solution.
In addition, in FIG. 3, description of an acid injection line, a waste liquid line, a valve, etc. is abbreviate | omitted.

  As a result, when there is a sign of blockage in the main chlorine injection pipe 16A, it is possible to continue the injection of the chlorine water 13 even during the cleaning of the main chlorine injection pipe 16A, and the inner surface of the seawater introduction pipe 11a that is the plant intake pipe The risk of biofouling can be reduced.

  Moreover, the injection of the acid cleaning water 17 is set as appropriate depending on the scale adhesion state or the like, between continuous injection and intermittent injection.

When using a strong acid to dissolve the scale in the chlorine injection pipe 16A, if the amount of scale attached is large, gas generated by the scale dissolution reaction may be generated at one time.
Generation of such a large amount of gas is not preferable because the pressure in the pipe increases.
Therefore, by intermittently injecting the acid cleaning water 17 from one end of the pipe, it is possible to suppress an increase in pressure in the chlorine injection pipe 16A.
In the case of intermittent injection, the gas generation status, CO ₂ concentration, and the like may be observed after the acid cleaning water 17 is injected to determine the timing of the acid injection interval.
In addition, a vent for venting gas may be provided in advance at a location where gas in the pipe is likely to accumulate.

FIGS. 4-1 and FIGS. 4-2 are figures which show an example which arrange | positioned the chlorine injection piping in the seawater introduction pipe.
As shown in FIGS. 4A and 4B, a chlorine injection pipe 16 may be installed along the inside of the seawater introduction pipe 11a.
In such a case, the acid wash water 17 is introduced from the inlet side of the water intake 15 to remove the scale inside the chlorine injection pipe 16.
Also in FIG. 4B, the acid injection line, the waste liquid line, the valve, and the like can be installed as necessary.

A seawater electrolysis chlorine injection device according to an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same member as the structure of the seawater electrolysis-type chlorine injection apparatus of FIG. 1, and the description is abbreviate | omitted.
FIG. 5 is a diagram illustrating an example of installing a chlorine injection pipe in a land portion.

  As shown in FIG. 2, when the chlorine injection pipe 16 can be installed so as to be inclined obliquely from the land toward the water intake port 15 as shown in FIG. By repeating the operation, the internal scale can be removed. However, in the sea area where the power plant 11 is installed, it may be difficult to install the pipes at a constant pitch at an angle.

As shown in FIG. 5, when installing the chlorine injection pipe 16 in the land part Y, the long distance (for example, 2 to 5 km or more) is selected according to the terrain rich in the undulation of the land part Y. Therefore, it is necessary to route the chlorine injection pipe 16.
In such undulating terrain where there are peaks and valleys in the land portion Y, there are cases where valleys and peaks are formed in the chlorine injection pipe 16.

When removing the scale in the chlorine injection pipe 16 in which such ridges and valleys are formed, the valley of the chlorine injection pipe 16 as in the seawater electrolysis chlorine injection apparatus 10 according to this embodiment. The parts are closed with the first valve V ₁ and the second valve V ₂ to form a closed space, and the acid wash water 17 is introduced into the closed space through the acid injection line L ₁ provided near the valley, The inside of the enclosed space is washed. At the same time, a waste liquid line L ₃ is provided at the mountain portion to discharge the acid cleaning waste liquid 19.

In particular, since Unit 1 and Unit 2 of the power plant 11 are in the early stages of power generation facilities, the chlorine injection pipe 16 has a relatively high design likelihood, but when Unit 3 or Unit 4 is reached, chlorine along the seabed X It may be difficult to install the injection pipe 16.
In such a case, when the chlorine injection pipe 16 supported by the support column 21 has a peak and a valley, a first valve V ₁ and a second valve V ₂ are provided in the vicinity of the valley, and each of these valves is provided. An acid injection line L ₁ is provided in the vicinity, the acid washing water 17 is introduced from both valley sides, the scale is removed, and the waste liquid is discharged from the waste liquid line L ₃ provided in the peak portion.

DESCRIPTION OF SYMBOLS 10 Seawater electrolysis type chlorine injection apparatus 11 Power generation plant 12 Seawater 13 Chlorine water 14 Seawater electrolysis apparatus 15 Water intake 16 Chlorine injection piping 17 Acid cleaning water 18 Acid tank 19 Acid cleaning waste liquid 20 Acid waste liquid storage tank

Claims (4)

When seawater is used as cooling water to be supplied to a power plant, a seawater electrolysis chlorine injection device for introducing chlorine water into the seawater,
Chlorine water supplied from the seawater electrolysis device of the seawater electrolysis chlorine injection device, a chlorine injection pipe for introducing the chlorine water to the vicinity of the water intake of the power plant,
An acid cleaning means for cleaning the chlorine injection pipe with acid cleaning water when there is a sign of a decrease in the supply rate of the chlorine injection pipe;
A seawater electrolysis chlorine injection device comprising an acid waste liquid storage tank for storing acid cleaning waste liquid. In claim 1,
The chlorine injection pipe toward the intake, provided it is to gradually inclined,
A plurality of valves are provided at predetermined intervals from the front end side of the chlorine injection pipe to form a closed space, and an acid injection line is provided in the vicinity of the valve on the low slope side in the closed space to provide the acid cleaning inside the closed space. Introducing water and cleaning the interior,
A seawater electrolysis chlorine injection device, characterized in that a waste liquid line is provided in the vicinity of a valve on the side where the inclination of the closed space is high, and the acid cleaning waste liquid is discharged. In claim 1,
The chlorine injection pipe is provided et been continuously along the crest of the land or the seabed and valleys,
Closing the valleys of the chlorine injection piping with a valve to form a closed space,
In the trough, an acid injection line is provided, the acid cleaning water is introduced into the closed space from the trough side, and the inside is washed,
A seawater electrolysis chlorine injecting apparatus, characterized in that a waste liquid line is provided in a mountain and the acid cleaning waste liquid is discharged. When seawater is used as cooling water to be supplied to a power plant, a seawater electrolysis chlorine injection device for introducing chlorine water into the seawater,
A seawater introduction pipe for introducing seawater into the power plant through the water inlet;
A chlorine injection pipe that extends into the seawater introduction pipe and introduces chlorine water supplied from the seawater electrolysis apparatus of the seawater electrolysis chlorine injection apparatus to the vicinity of the water intake;
When there is a sign of a decrease in the supply rate of the chlorine injection pipe, acid cleaning means for cleaning with acid cleaning water from the tip side of the chlorine injection pipe;
A seawater electrolysis chlorine injection device comprising an acid waste liquid storage tank for storing acid cleaning waste liquid.

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