What conditions are needed for cathodic protection of pipelines

What conditions are needed for cathodic protection of pipelines

1) Pipe must be electrically continuous, for welded pipe, this is not a problem. If there are socket joints in the pipe, flanged valves should be bonded with jumper connections.

2) The pipeline segment to be protected must be insulated from other buried pipelines, cables and grounding poles, and can be insulated joints or flanges; When the casing passes through, the insulation pad should be installed between the main pipe and the casing.

3) When the pipeline passes through other pipelines, cables, or buried structures, the spacing should be greater than 0.4 meters. If the spacing is less than 0.1 meters, insulation boards should be installed between them to provide mechanical protection and prevent corrosion interference. When the pipe is parallel to other structures, the spacing should be greater than 10 m.

How to do gas pipeline cathodic protection solder joint anticorrosion?

Peel off the anticorrosive layer, use a chisel to open a 2cm wide and 10cm long mouth, remove the anticorrosive layer to expose the metal, dig open, remove the surface layer with a file to expose the metal, solder with aluminum flux, drop on the hot melt glue, connect the metal wire with a bow, fixed with the contraction band, and finally use the large contraction band anticorrosive.

How is the cathodic protection current from the auxiliary anode to the pipe? Is the pipe anticorrosive coating not insulated? How did you get in?

Because the coating has many leakage points that can cause corrosion of the pipe, cathodic protection is used. Cathodic protection current through a medium, such as soil through leakage again apply to tube surface, let originally currents flowing out of a pipe end, and increases the excess current pipeline surface polarization, polarization film formation, when polarization film growth reaches a certain thickness, the membrane will be compensatory coating effect, it can resist corrosion damage on the surface of pipeline corrosion medium.

Pipeline cathodic protection potential test pile, current test pile, insulation test pile how wiring....

The potential test pile is directly connected to the test pile by the line drawn from "magnesium alloy sacrificial anode material package", assuming node A. The e pipe thermite welding line is directly connected to the test pile at point B, and the reference electrode is connected to the test pile at point C. The dc at points A and C is the open circuit potential tested with A digital multimeter. The measuring current (10A) is the working current. Then. Point A connecting point B and point C is the load voltage and current test. That's what Dashikai does. The insulation of the insulation valve must be done first. The test again

What is the cathodic protection test pile

The test pile is an essential device in the cathodic protection system, which is mainly used to detect the effect and operation parameters of cathodic protection. According to the material, the test pile can be divided into steel tube test pile, FRP test pile, concrete test pile, plastic test pile and other categories, in which the steel tube test pile can also be divided into carbon steel and stainless steel material. Test pile can be divided into potential test pile, current test pile, insulation test pile and so on. The test pile is mainly used to test the protection potential, and can be used to test the protection effect of the cathodic protection system of metal structures such as storage tanks, pipelines and wharf facilities. It can also be used for testing the sacrificial anode current and insulating joint

How to calibrate portable saturated copper sulfate reference electrodes for cathodic protection testing?

Do you want to calibrate the reference electrode or calibrate your data?

If you want to calibrate a reference electrode then you have to buy a standard calomel electrode and you have to calibrate it, you have to calibrate it experimentally, you have to calibrate it and you can look it up.

If the reference electrode is ok, you can measure the voltage by burying the reference near the measurement and connecting one end of the multimeter to the reference and the other end to the measurement.

Function and usage of reference electrode for cathodic protection

Reference electrode usage: mainly used for 1, accurate monitoring of cathodic protection state. Potential measurement for sacrificial anode protection.

2, in the applied current cathodic protection system, as an automatic control of the stable signal source, suitable for buried pipelines and underground metal structures cathodic protection engineering.

3, can be buried in the need to monitor and can not enter the position. Such as: large container bottom center location; Inaccessible locations between underground fuel storage and chemical storage tanks; Urban roads under the network, etc. Can be buried in advance during the construction of the project, long-term use.

4. Telemetry signal source for cathodic protection of pipeline.

Why does the reference electrode have a sealing cap and what is the sealing cap? What is Luggin doing? How does it work?

There are two rubber caps on the reference electrode to prevent volatilization of KCl solution. When used, the top cap is covered and the bottom cap must be removed so that the electrode can contact the solution outside the electrode. Luggin is a lujin capillary and acts as a salt bridge.

In electrochemical test, why is saturated calomel electrode used as reference electrode?

SCE as a reference electrode is very stable and KCl only needs to be saturated and easy to make the electrode potential is 0.244V, it seems to be basically unchanged; A standard hydrogen electrode, which is easy to calculate, is very difficult to control and the pressure of H2 is exactly 1 bar and you don't use it

In cathodic protection, why is it necessary to set up testing piles where pipelines cross rivers, highways and railways?

According to my personal understanding, river, highway and railway belong to the three through project, which basically belong to the single drawing pipe jacking. He needs the project and supervision inspection qualified before the next process of construction.

Under what conditions should we take cathodic protection measures for buried steel pipe?

In the long distance buried pipeline, in order to ensure that the pipeline is not easy to be corroded in humid environment, can use cathodic protection measures! There are several ways!

What is the role of the confluence point in a cathodic protection system? Is the impressed current potentiostat used in pairs with the auxiliary anode, or are several power supplies supplied to multiple anodes together

The junction point is the cathode cable access point, and the potential is negative compared with other parts of the pipeline. The potentiostat and the auxiliary anode can be used in pairing or combined for common use, depending on the actual situation.

In the oil production pipeline, when the applied current cathodic protection is used, there should be an insulating flange connection between the protected pipe section and the unprotected pipe section.

In the oil production pipeline, when the applied current cathodic protection is used, there should be an insulating flange connection between the protected pipe section and the unprotected pipe section.

The external wall of oil pipeline is protected by impressed current cathodic protection law in a oil production plant, but such a phenomenon occurs:

1. Pipe perforation is concentrated near both sides of the insulation flange (50cm~100cm), and the perforation frequency is high.

2, cathodic protection equipment for many years discontinued pipe perforation but very few.

From these two characteristics, this phenomenon has a close relationship with the CATHOdic protection system, even a causal relationship. Excuse me what is the biggest possible cause of this situation, who has seen this situation, whether there is a better solution?

Answer: the grounding battery should be added on both sides of the insulation flange.

Is LPG used for tank cathodic protection? why

LPG tanks are usually located on the ground, where contact with soil can cause corrosion, so cathodic protection is required to ensure that the tanks do not corrode or extend their service life.

Is cathodic protection necessary for steel tubes after they have been corroded

A: no, no

Cathodic protection, that is, to sacrifice the negative polarity to achieve corrosion protection, since the corrosion has been done, there is no need. I feel the need

I heard that cathodic protection works only when the metal is in water, but not when it's dry?

You have to figure out why do you do cathodic protection

And the four elements of corrosion are: anode, cathode, electrolyte, metal channel

Water is an electrolyte, and without an electrolyte, there would be no flow of electrons and corrosion would not occur, so cathodic protection would not work in dry conditions.

Note: ① Pure water (such as distilled water) is not an electrolyte. Natural water is a conductive solution formed by the presence of a variety of ions (Cl -, SO2 -,0h-, etc.).

(2) The electrolyte is not only limited to ordinary water, oil, any liquid that can provide electron flow can be.

Or no area is permanently dry, only slightly varying degrees of moisture, and as long as there is moisture, the electrical current the system puts into the car will do its job. Any area of the rainy season to the car will bring a lot of oxidation rust damage to the car.

Low temperature metal surface is more likely to condense air water, and the formation of water film. The water film, plus an abundance of similar electrons, forms a coating.

The electrons in this shell are consumed primarily by oxidation and rust, and the system continues to replenish the positrons. Let the atoms of the metal line up behind the cover.

In the absence of water, the flow of electrons can be added to oxide film or paint.

Or if the soil is dry, the resistivity is high, and specific cathodic protection materials can be considered. Absolute dry conditions should be rare

What are the internal and external anti-corrosion measures of the commonly used open steel pipe laying?

Primer:

Zinc - rich primer epoxy strength heavy - paste primer epoxy cloud iron intermediate paint

Top coat: the top coat is determined by the medium

Galvanized steel pipe for fire fighting (DN< 100) need to do internal and external corrosion

Don't need. Steel pipes are galvanized to prevent corrosion. However, if welding is used, the welding part should be antiseptic

What are the commonly used anti-corrosion measures in chemical production process?

1, the most used is anticorrosive paint, but according to your process environment on the bottom, middle, top paint requirements.

2, can choose anticorrosive material of pipes, equipment, such as steel lining ptfe, steel lining PO, rubber, FRP pipe, UPVC and PE and other plastic pipes, graphite equipment.

3. Metal pipes can also be covered with glass cloth and epoxy resin brush. The number of layers of glass cloth package according to the process environment.

4, with a specific metal block and metal pipe connection, the use of positive and negative ion principle for anticorrosion, that is, cathode anticorrosion, but this should be according to your process environment consulting professional units in this respect, to the Internet can be found.

5, if it is necessary to anti-corrosion pool with epoxy resin and anti-corrosion tile or anti-corrosion cement (anti-corrosion cement is suitable for less water concentrated acid)

In fact, one of the most important is to always pay close attention to the scene of running dripping, patting acid and alkali gas and liquid.

What anticorrosive coatings are commonly used in petrochemical enterprises?

Epoxy zinc rich or zinc free primer, epoxy iron intermediate, polyurethane top coat

I would like to ask how much money is needed to do internal and external anticorrosion on the steel pipe with epoxy coal asphalt, ordinary grade and reinforced grade

Coal tar epoxy paint into primers and paint, according to the requirements of construction should be 2 times, paint 2 times normal level antiseptic don't tie up the glass ribbon, cheap primer 14, 15, paint to find regular production enterprises, if again low price, the inside of asphalt, epoxy resin, less corrosion effect is bad, now paint market is too messy, anti-corrosive paint too many fakes, The price is cheap, the strengthening is more wrapped glass ribbon in the middle, a bit of trouble, but the anti-corrosion effect is good.

Technical specification for cathodic protection of buried steel pipelines (GB/T21448-2008

Offshore oil rig

Offshore structures used primarily for drilling Wells. Install drilling, power, communication, navigation and other equipment, as well as safety and life-saving and personnel living facilities. Offshore oil and gas exploration and development indispensable means. There are mainly jack-up and semi-submersible drilling platforms.

① Jack-up drilling platform

The platform is composed of a platform, a pile leg and a lifting mechanism. The platform can rise and fall along the pile leg and generally has no self-propelled capability. In 1953, the first jackup platform was built in the United States. This kind of platform has strong adaptability to water depth, good working stability and rapid development, accounting for about 1/2 of the total number of mobile drilling units. During the work, the pile leg is lowered into the seabed, the platform is raised to a safe working height above the sea surface, and the pile leg is preloaded to ensure that the pile leg does not sag when the platform meets a storm. After completion, the platform was lowered to the surface, the pile legs were pulled out and all of them lifted, and the entire platform floated on the surface and was towed to the new well location.

(2) Semi-submersible drilling platform

The upper part is a work deck and the lower part is two lower hulls connected by supporting columns. At work, the hull dives into the water, the deck is at a safe height on the water, the waterline area is small, the wave influence is small, the stability is good, the self-support is strong, and the working water depth is large. After the newly developed dynamic positioning technology is applied to the semi-submersible platform, the working water depth can reach 900 ~ 1200 meters. Compared with the jack-up drilling platform, the semi-submersible has the advantages of large working water depth and flexible movement. The disadvantages are large investment, high maintenance costs, the need for a complex set of underwater equipment, effective utilization rate is lower than the jack-up rig.