Research On Suture Technique Of 3PE Anticorrosion Coating For Buried Steel Pipeline

The cost overseas is higher than that at home for the associated suture technique to 3PE antisepsis. The technique has not been mature in our country where the antisepsis classifications at sutures constructed by heat-shrinkage belt (cover) and liquid epoxy coating plus heat-shrinkage belt (cover) cannot reach that of 3PE antisepsis, it is difficult to ensure uniform warm-up temperature on buried steel big pipelines by common suture process. The uniform warm-up temperature causes worse suture and cannot fuse antisepsis layers at suture and on pipe. Some defects shall appear at suture because the connection between antisepsis layers at suture and on pipe is often destroyed by the actions of temperature and soil stress. These defects shall play down the integrated antisepsis classification, make the antisepsis effect of common antisepsis layers worse than that of 3PE antisepsis layers, and shorten the life-span of pipelines.Aiming at the problems such as unequally preheating temperature in a buried steel big pipeline, this research has been done by referring and improving the existing suture methods at home and abroad. At beginning, the effect of warm-up on the antisepsis layers of pipelines is analyzed. Then the prescription of epoxy power dope is tried and improved. And after that, the in-site facilities to coat epoxy power dope, the fabrication methods and construction process of the PE composite belt are developed. Finally, 3PE antisepsis coating is tested at sutures on pipelines. A set of suture process, clinkery epoxy plus copolymer gooey plus polyethylene, and its relevant facility have been developed after the above studies. This new set process and its relevant facility have filled up the gap on 3PE antisepsis for suture as an effective and practical way for buried steel big pipeline. As compared to suture process overseas, the 3PE antisepsis takes advantage of simpler facility, more convenience construction and lower cost. This new 3PE material has served some oil & gas pipelines inland, and decreased their investment and run cost with distinct economical benefit.