JPH064157B2 - How to clean the inside of the pipe - Google Patents

Description

TECHNICAL FIELD The present invention mainly relates to a method for cleaning the inside of a pipe for removing deposits on the inner wall of a submarine pipe, and also for cleaning a transport pipe for transporting various fluids such as gas and water. Available for

[Background Art and its Problems] As a method of cleaning the inside of a seabed or a transportation pipe for various fluids, a plurality of pigs are inserted into the pipe, and a cleaning agent is sealed between these pigs, There is known a method in which the air is run in the pipe by air pressure for cleaning.

However, since this method uses a water-soluble detergent as the cleaning agent, the wax and oil adhering to the inner wall of the pipe are not completely removed, and there is a drawback that the cleaning property is lowered particularly in cold regions in winter.

Therefore, in order to completely remove the wax and oil, an organic solvent may be used as a cleaning agent, but if an organic solvent is used, there is a danger of explosion due to contact with air for pressure feeding.

[Object of the Invention] An object of the present invention is to provide a method for cleaning the inside of a pipe, which can easily and surely remove deposits in the pipe even in a cold region and at the same time improve safety. .

[Means and Actions for Solving Problems] Therefore, in the present invention, in order to easily and surely remove the adhered matter, a pig and a pig other than the outermost end of the plurality of pigs inserted into the pipe are Encapsulating a degreasable organic solvent as a cleaning agent in the meantime, and at the same time, encapsulating the organic solvent in order to prevent the problem associated with using an organic solvent, that is, the explosion caused by the contact between the organic solvent and the air for pressure feeding. A non-explosive sealing liquid is enclosed between the end pig and the outermost pig, respectively, thereby achieving the above object.

Therefore, the method of the present invention will be specifically described with reference to FIG.

First, a plurality of pipes, here four pigs 2 ₁ to 2 ₄ are inserted into a pipe 1 to be cleaned, for example, a seabed pipe or a transportation pipe for transporting various fluids such as gas and water. These pig 2 ₁ -
2 ₄ is made of a material having elasticity, for example, a urethane foam or the like, can liquid seal liquid to be encapsulated therein in close contact with the pipe 1, and shaped to steering along the pipe 1, for example of the short cylindrical body It is molded into a cannonball shape with one end chamfered or spherically processed.

Subsequently, the organic solvent 3 is sealed between the pigs 2 ₂ and 2 ₃ except the outermost pigs 2 _{1 and} 2 ₄ among the pigs 2 ₁ to 2 ₄ . Examples of the organic solvent 3 include degreasable alcohols and ketones, hydrocarbon oils having a boiling point of 100 ° C. or higher,
Kerosene or light oil is particularly preferable. The enclosed amount is appropriately determined according to the inner diameter of the pipe 1 and the length of the cleaning section.
Since static electricity is generated at the time of collecting the waste liquid, it is desirable to add an antistatic agent (generic name ASAIII) in order to suppress the static electricity. The addition amount of the antistatic agent may be, for example, 5 ppm or more with respect to 10K of the organic solvent.

Further, a non-explosive seal liquid 4 is sealed between the pigs 2 ₂ and 2 ₃ at each end for sealing the organic solvent 3 and the pigs 2 ₁ and 2 ₄ at the outermost ends. The seal liquid 4 prevents direct contact between the organic solvent 3 and the compressed air, prevents explosion caused by the contact between the two, and at the same time makes the inner wall deposits in the pipe 1 readily preliminarily dissolved. For example, water or A foaming detergent is used. When the effervescent detergent is used, the adhering matter adhered to the inner wall of the pipe 1 can be easily washed, so that the adhering matter can be easily removed by the organic solvent.

In this state, compressed air is supplied to the one of the pipe 1, the pipe these pig ₂₁ to ₂₄ by the air pressure 1
Run along the inside. Compressed air pumping has the advantage that compressed air itself is more easily obtained and cheaper than other high pressure fluids. At this time, the contact between the compressed air and the organic solvent is prevented by the seal liquid, so there is no danger of explosion or the like due to the contact between the two. When the pigs 2 _{1 to} 2 ₄ run in the pipe 1, the deposits in the pipe 1 are softened and washed by the seal liquid 4 and then completely removed by the chemical action of the organic solvent 3. These pigs 2 ₁ to 2 ₄ are reciprocated depending on the state of removal of the deposits in the pipe 1. Normally, after traveling the cleaning section back and forth 2-3 times, the organic solvent 3
And the seal liquid 4 is replaced with a new one,
It is enough to do three times.

[Example] An example in which the method of the present invention is applied to the cleaning of a submarine pipe will be described with reference to FIG.

In the figure, a piglancher catcher 13 is connected to one end of the seabed 12 having an inner diameter of about 1191 mm and a length of about 3400 m on the seaverse 12 side. This pig launcher catcher 13 has two adjusting valves 14A, 1
Valve 1 for introducing compressed air whose pressure is adjusted by 4B
5 and a valve 16 for opening to the atmosphere are provided respectively.

Further, a piglancher catcher 21 is also connected to the other end of the seabed pipe 11 on the land side. In this pig launcher catcher 21, two adjusting valves 22A and 22B are provided.
A valve 23 for introducing compressed air whose pressure is adjusted by
A valve 24 for opening to the atmosphere is provided.
As a result, four pigs 2 ₁ to 2 ₄ are sequentially inserted into the submarine pipe 11 from the pig launcher catcher 21, and the organic solvent 3 is placed between the pigs 2 ₂ and 2 ₃ excluding the outermost end among these pigs. After sealing the sealing liquid ₄ between the pigs 2 ₁ and 2 ₂ and the pigs 2 ₃ and 2 ₄ , respectively, first open the valve 16 on the piglancher catcher 13 side, and open the valve 23 on the opposite side to compress it through the valve 23. Air is pipe 1
Since these are introduced to the other end side of 1, the pigs 2 ₁ to 2 ₄ run toward the one end side of the pipe 11. Just before reaching the pig ₂₁ to ₂₄ is the pig launcher catcher 13 side, closing the valve 23, in turn, opens the valve 24 of the pig launcher catcher 21 side, therewith to open the other end of the valve 15, compressed through valve 15 since air is introduced into one end of the pipe 11, the pig ₂₁ to ₂₄ is traveling toward the other end of the pipe 11. The pig ₂₁ to ₂₄ can be reciprocally travel by this Kukaee Mr.

The pigtailer catcher 21 has the valve 23,
In addition to 24, a valve 31 for introducing nitrogen gas, together with a valve 33 is provided for communicating the pig launcher catcher 21 and release圧槽23, pig ₂₁ to ₂₄
Valves 42A, 42B and 42C are provided for discharging the cleaning waste liquid enclosed between them to the waste liquid receiving tank 41. As a result, after the pigs 2 _{1 to} 2 ₄ normally travel back and forth 2 to 3 times, immediately before the cleaning waste chemicals are collected in the waste liquid receiving tank 41, the nitrogen gas passes through the valve 31 and the piglancher catcher 2 is discharged.
The mist is prevented from being ignited by being introduced into the pressure release tank 32 through the valve 34 at the same time as being introduced into the mist 1.

The cleaning waste chemical liquid enclosed between the pigs 2 _{1 to} 2 ₄ is stored in the valve 42.
It is sent to the waste liquid receiving tank 41 through A to 42C. The pipe outlet to the waste liquid receiving tank 41 is of bell-mouth type so as to be discharged into the liquid to prevent the mist from scattering. A coiled ground wire 42, which is connected to the piping and the tank body and is connected to the ground rod 43, is inserted into the waste liquid receiving tank 41 to prevent these from being charged.

In such a system, first, kerosene is placed between the pigs 2 ₂ and 2 ₃ at 20K, and between the pigs 2 ₁ and 2 ₂ and the pigs 2 ₃ and 2 _{4 respectively.}
10K of water is enclosed between each of them and these pigs 2 ₁
After 3 times round trip along a 21 to ₂₄ of the pipe 11, to recover these cleaning waste liquid medicine. Then, after changing to new kerosene and water, the same running is repeated. As a result of lowering the sealed amount of kerosene to 10K after the second time, the deposits in the pipe 11 were completely removed by the third cleaning.

[Advantages of the Invention] As described above, according to the present invention, since the organic solvent is used, it is possible to easily and surely remove the deposit in the pipe, and to seal the direct contact between the organic solvent and the air for pressure feeding. Since it is protected by liquid, there is no danger of explosion due to contact with them, and safety can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the method of the present invention, and FIG. 2 is a diagram showing a system in which the method of the present invention is applied to cleaning of seabed piping. 1 ... Piping, 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ ... Pig, 3 ... Organic solvent,
4 ... Seal liquid.

Continuation of the front page (56) References JP-A-58-92488 (JP, A) JP-A-54-91965 (JP, A) Actual opening 48-79452 (JP, U) Actual opening Sho-54-71860 (JP , U) JP-B 43-10314 (JP, B1) JP-B 54-43308 (JP, B2) JP-B 53-13112 (JP, B2)

Claims (5)

[Claims] 1. A method of inserting a pig into a pipe and running the pig by air pressure to clean the inside of the pipe, wherein a plurality of pigs are inserted into the pipe except for the outermost end thereof. And an organic solvent between the pig and the pig, and a non-explosive seal liquid between each end that encloses the organic solvent and the pig at the outermost end. A method for cleaning the inside of a pipe, characterized by cleaning the inside. 2. A method for cleaning an inside of a pipe according to claim 1, wherein kerosene is used as the organic solvent. 3. A method for cleaning an inside of a pipe according to claim 1, wherein light oil is used as the organic solvent. 4. The method for cleaning the inside of a pipe according to claim 2 or 3, wherein an antistatic agent is added to the kerosene or the light oil. 5. A method for cleaning an inside of a pipe according to any one of claims 1 to 4, wherein water or a foaming detergent is used as the sealing liquid.