JPH10204664A - Formation of corrosion inhibiting film on aluminum brass pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a corrosion inhibiting film on the inside wall surface of a pipe for a short time by dissolving a material containing ferrous ion and ozone in water in a prescribed ratio of form a ferric oxide colloid in a vessel and after removing residual ozone from the colloid, injecting into an aluminum brass pipe. SOLUTION: Sea water as a cooling water is forcibly fed to a cooling water flow pipe 2 arranged, for example, in a heat exchanger 1 and made of the aluminum brass pipe from a feed port 3. Ozone is produced in an ozonizer 7 using oxygen produced in a PSA 6, supplied to a 1st tank 8, in which a plain water is stored, and dissolved. The ferric oxide colloid is formed by supplying ferrous sulfate to the 1st tank 8 from an iron ion supply device 9. The resultant ferric oxide colloid is supplied to a 2nd tank 11 and is injected to the cooling water flow pipe 2 through a membrane filter 15 after ozone in the colloid is discharged by nitrogen supplied from an equipment 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an anticorrosion film on an aluminum brass tube.

[0002]

2. Description of the Related Art Conventionally, river water, seawater or the like has been used as cooling water for cooling a heat exchanger. As the cooling pipe through which the cooling water flows, an aluminum brass pipe is often used. As means for preventing the corrosion of the aluminum brass tube, there can be mentioned a method for preventing corrosion of a copper alloy tube material described in Japanese Patent Publication No. 57-40222. In the technology described in this publication, seawater containing 10 to 200 PPm of ferrous ions or ferric ions or a mixture of both ions is passed through the copper alloy and, at the same time, passed through a sponge ball in a timely manner. An anticorrosion film is formed on the inner wall of the pipe. That is, the iron ions injected into the seawater react with dissolved oxygen in the seawater to form a hydrated iron oxide colloid, which adheres to the inner wall surface of the tube to form an anticorrosion film.

[0003]

However, in the above prior art, the time required for iron ions to react with dissolved oxygen in seawater to form a hydrated iron oxide colloid is long (several weeks to several weeks). (Several months), and there was a problem that an anticorrosion film could not be quickly formed on the inner wall surface of the pipe.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for forming an anticorrosion film on an aluminum brass tube, which can form an anticorrosion film on the inner wall surface of the tube in a short period of time. Is to do.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a material containing ferrous ions and ozone are dissolved in water at a predetermined ratio in a container, thereby oxidizing the material. The gist of the present invention is to form a ferric colloid, remove almost residual ozone from the colloid, and then inject the colloid into an aluminum brass tube to form an iron oxide film on the inner wall surface of the tube.

According to a second aspect of the present invention, the gist of the first aspect is that, after the colloid is formed, nitrogen is blown into a container to discharge ozone in the colloid to the outside. .

According to a third aspect of the present invention, in the first or the second aspect of the present invention, a colloidal oxide having a particle diameter of not more than a predetermined particle size is provided in a path connecting the container and the aluminum brass tube. The gist is that a filter that allows the passage of ferrous iron is provided.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, a cooling water flow pipe 2 made of an aluminum brass pipe is provided in the heat exchanger 1. A pump P is connected to a supply port 3 of the cooling water flow pipe 2, and the pump 4 draws in seawater as cooling water and pumps the seawater from the supply port 3 into the cooling water flow pipe 2. The seawater pumped into the cooling water flow pipe 2 is discharged from the discharge port 5 to the outside.

[0009] An ozonizer 7 is connected to the oxygen producing device 6. The ozonizer 7 produces ozone from oxygen produced by the oxygen producing device 6 and supplies it to a first tank 8 as a container. Fresh water is stored in the first tank 8.
Further, an iron ion supply device 9 is connected to the first tank 8. By dissolving ferrous sulfate and ozone supplied from the ozonizer 7 in fresh water in the first tank 8, a colloid of ferric oxide is generated. In the present embodiment, the ferrous sulfate has a concentration in the aqueous solution of 0.5 to 0.5.
It is supplied into the first tank 8 so as to be 1 ppm. The ozone is 50 to 100 per liter of the aqueous solution.
mg is supplied into the first tank 8. Also,
An ozone discharge pipe 10 for discharging excess ozone stored in the tank 8 to the outside is connected to the first tank 8.

A second tank 11 is connected to the first tank 8 via a pump 16.
The colloid formed in the first tank 8 is supplied into a second tank 11 as a container. Also, the second tank 11
Is connected to a nitrogen supply device 12 and an ozone discharge pipe 13. Ozone in the colloid supplied into the second tank 11 by the nitrogen supplied from the nitrogen supply device 12 into the second tank 11 (ozone that could not be discharged by the first tank) is discharged to the outside through the ozone discharge pipe 13. Is done. Also,
The second tank 11 and the supply port 3 side of the cooling water flow pipe 2 are connected by a colloid supply pipe 14. A membrane filter 15 is connected in the middle of the colloid supply pipe 14. The colloid in the second tank 11 is injected from the colloid supply pipe 14 through the membrane filter 15 into the cooling water flow pipe 2 as the pump 17 is driven.

Next, the operation of the embodiment will be described. First, when the pump 4 is driven, seawater is sucked from the supply port 3 of the cooling water flow pipe 2. At the same time, a colloid of ferric oxide is generated in the first tank 8. The colloid generated in the first tank 8 is supplied to the pump 1
6 is fed to the second tank 11 by pressure. Colloid is second
When pressure-fed to the tank 11, the ozone in the colloid is almost discharged to the outside in the second tank 11. afterwards,
The colloid in the second tank 11 is pumped into the cooling water flow pipe 2 together with seawater from the supply port 3 of the cooling water flow pipe 2 through the membrane filter 15 from the colloid supply pipe 14 by the pump 17. The membrane filter 15 permits the flow of only the colloid having a particle size of a predetermined particle size or less (2 to 3 microns or less in this embodiment).

When the colloid having a particle diameter equal to or less than the predetermined particle size is flown in the cooling water flow tube 2 together with seawater for a predetermined period (10 to 30 days), an anticorrosion film (iron oxide film) is formed on the inner wall surface of the cooling water flow tube 2. Is done.

In the present embodiment, the following effects can be obtained by forming the anticorrosion film on the inner wall surface of the cooling water flow pipe (aluminum brass pipe) 2 as described above.

Conventionally, iron ions are injected into seawater, and the dissolved oxygen in the seawater reacts with the iron ions to form a hydrated iron oxide colloid in the cooling water flow tube. The anticorrosion film was formed by adhering.

On the other hand, in the present embodiment, the colloid forming the anticorrosion film is generated in the first tank 8 in advance, and the colloid generated in the tank 8 is injected into the cooling water flow pipe 2. An iron oxide film was formed on the inner wall surface of the tube. That is, conventionally, by injecting ferrous ions into the cooling water, the molten oxygen in the cooling water and the ferrous ions are combined to form a colloid, which adheres to the inner wall of the pipe, thereby forming an iron oxide film on the inner wall of the pipe. However, in the present embodiment, after the colloid is actively generated outside the cooling water flow tube 2, the colloid is injected into the cooling water flow tube 2 to quickly and surely form the iron oxide film. It can be formed on the inner wall surface of the cooling water flow tube 2.

The colloid injected into the cooling water flow tube 2 is limited to a particle having a particle size of a predetermined particle size or less (2 to 3 microns or less) by using a membrane filter 15. The reason is that a colloid having a particle diameter exceeding a predetermined particle diameter is unlikely to adhere to the inner wall surface of the cooling water flow tube 2, so that an iron oxide film is not easily formed. That is, in the present embodiment,
By injecting only the colloid having a small particle size into the cooling water flow tube 2, the iron oxide film can be formed on the inner wall surface of the cooling water flow tube 2 more quickly.

Further, as the particle size of the colloid increases, the transparency of the colloid decreases. Therefore, when a colloid having a large particle diameter is injected into the cooling water flow pipe 2, turbid seawater is discharged from the discharge port 5 of the cooling water flow pipe 2, and the appearance becomes poor. However, in the present embodiment, since the colloid having a small particle diameter is injected into the cooling water flow pipe 2, the transparency of the discharged seawater is also high, and the appearance is good.

After the colloid was generated in the first tank 8, nitrogen was blown into the second tank 11 to discharge ozone in the colloid to the outside. As a result, even when the colloid mixes with the seawater in the cooling water flow pipe 2, the generation of toxic substances such as residual oxidants generated by the reaction between the ozone and the impurities of the seawater can be prevented, and the adverse effect on the environment can be reduced.

The above embodiment may be embodied instead of the following. -The particle size of the colloid that the filter 15 allows to pass may be appropriately changed. -The 1st tank 8 and the 2nd tank 11 may be integrated and embodied.

The cooling water may be embodied in place of fresh water other than seawater. -The concentration of ferrous ion and ozone in the aqueous solution in the first tank 8 may be changed as appropriate and embodied.

[0021]

According to the first aspect of the present invention, a colloid of ferric oxide is formed in advance, and then the colloid is injected into an aluminum brass tube, whereby the colloidal oxide is formed in the aluminum brass tube. The iron oxide film can be formed on the inner wall surface of the aluminum brass tube in a shorter period of time than the conventional technique for producing ferric iron.

According to the invention of claim 2, according to claim 1,
In addition to the effects of the invention described in the above, after the colloid is generated, by blowing nitrogen into the container and discharging ozone in the colloid to the outside, even if the colloid and seawater are mixed in the aluminum brass tube, the ozone and ozone are mixed. It is possible to prevent the generation of toxic substances generated by the reaction with impurities such as seawater.

According to the third aspect of the present invention, the first aspect is provided.
Alternatively, in addition to the effect of the second aspect of the present invention, a filter that allows the passage of a colloid having a particle diameter equal to or less than a predetermined particle size is provided in a path connecting the container and the aluminum brass tube.
As a result, a colloid having a particle diameter exceeding a predetermined particle diameter that does not easily adhere to the inner wall surface of the tube is prevented from being injected into the tube, and an iron oxide film can be formed on the inner wall surface of the tube in a shorter time. That is, by injecting only the colloidal ferric oxide having a small particle size into the tube, the iron oxide film can be more quickly formed on the inner wall surface of the tube.

Further, as the particle size of the colloid increases, the transparency of the colloid decreases. Therefore, when a colloid having a large particle size is injected into the tube, turbidity occurs in seawater discharged from the tube, and the appearance also becomes poor. However, by injecting a colloid having a small particle size into the tube, the transparency of seawater and the like discharged from the tube is high and the appearance is good.

[Brief description of the drawings]

FIG. 1 is a schematic circuit diagram of an anticorrosion film forming apparatus.

[Description of Signs] 1 ... heat exchanger, 2 ... cooling water flow tube as aluminum brass tube, 3 ... supply port, 8 ... first tank as container, 9 ... iron ion supply device, 11 ... second as container 2 containers, 14 ...
Colloid supply tube, 15 ... membrane filter.

Claims (3)

[Claims] 1. A ferrous oxide colloid is produced by dissolving a material containing ferrous ions and ozone in water at a predetermined ratio in a container, and after substantially removing residual ozone from the colloid, aluminum A method for forming an anticorrosion film on an aluminum brass tube, comprising injecting the film into a brass tube and forming an iron oxide film on the inner wall surface of the tube. 2. The method for forming an anticorrosion film on an aluminum brass tube according to claim 1, wherein after the colloid is generated, nitrogen is blown into the container to discharge ozone in the colloid to the outside. 3. The aluminum brass according to claim 1, wherein a filter that allows passage of a colloid having a particle diameter of not more than a predetermined particle size is provided in a path connecting the container and the aluminum brass tube. Method of forming anticorrosion film on pipe.