PRODUCTION • PROCESSING • HANDLING
PIPELINES O
PROTECTING Cathodic protection prevents corrosion of pipelines
ver the past three decades, corrosion problems have reduced the life expectancy of the pipe system down to only a few years. In
the USA alone, corrosion costs the industry more than a billion dollars a year. Pipeline corrosion is a natural
occurrence. Pipe material and essential properties deteriorate over time. Corrosion occurs due to electrochemical reactions of pipeline materials with their environment. You can find corrosion on the inside as well as outside surfaces. Like any other natural hazard, pipeline corrosion can cause a life-threatening failure. It can also cause expensive damage to the pipeline and related systems.
CATHODIC PROTECTION AGAINST CORROSION You can shield steel piping with cathodic protection to prevent corrosion. Tis technique reduces the corrosion of the metal surface. It does so by making the surface the cathode of an electrochemical
32
www.engineerlive.com
cell. Tis cathodic protection system works by applying a small current to the pipeline. Te technicians apply the current to the pipelines via units known as transformer- rectifiers, which convert AC electricity into DC. Te plant uses this electricity to lower the ‘energy’ of the pipeline. Te impressed cathodic protection shields some piping against corrosion. Tis type needs a non-conductive barrier between the process piping and the instrument. Te barrier protects it from the effects of electrical current. Tis measure, in turn, protects expensive electronics. AS-Schneider recommends using a dielectric isolation kit as a non-conductive barrier. Tis kit is for installation on the inlet flange connection of the manifold. It goes between the stabilised connector and the manifold.
Te firm has designed dielectric isolation kits to maintain the integrity of the pipeline. Tey also ensure the reliability of the piping system through safety and corrosion protection. Dielectric isolation kits provide
an effective seal and electrical isolation of flanges. Eliminating metal to metal contact halts static current. In this way, electronic harm to the instrument is prevented. Looking back a few years, when the firm was developing the dielectric isolation kit, there was a big challenge. Tat challenge was how to get a reliable, leak-tight connection for 6,000 psi (414 bar). Te connection had to be without an encapsulated gasket. Te company also had to tighten the bolting against a non-conductive soft plastic material. But it never backs down from a challenge: “Te challenge is one of the reasons why developing products is so much fun and is always exciting for me,” explains Markus Häffner, director of Design and Development, AS-Schneider. When it came to requirements for the dielectric isolation kit, in the beginning, this development did not look like a big challenge. However, in the end, the team had to make many tests to have a safe and reliable product.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
