Buried natural gas pipeline anti-corrosion technology progress

Natural gas is a clean, efficient, convenient and high-quality energy and chemical raw materials.

Its exploitation and utilization have significant economic, social and environmental benefits. With the further development of China's natural gas, the natural gas industry will be faced with new opportunities, is also faced with new challenges. The transformation of the original pipe network or laying new pipe network must emphasize safety, eliminate all risk. As can be seen from the pipe network at home and abroad, the cause of the accident, caused by man's destructive accidents accounted for a pipeline corrosion damage (including stress corrosion cracking) for second place. The latter are often difficult to detect, often overlooked, pipeline corrosion undoubtedly important agenda should be mentioned.

The high anticorrosion coating application

The primary means of domestic and international underground natural gas pipeline corrosion is appropriate based on the pipeline the geographical terrain, topography, geological conditions, covering supplemented by cathodic protection. Used paint: petroleum asphalt, coal tar enamel, epoxy paint. Domestic buried pipeline anti-corrosion commonly used petroleum asphalt paint. If the soil environment, microbial, no serious interference with the deep-rooted plants, be regarded as an affordable anti-corrosion layer.

Its flow properties are not suitable for high-temperature environment and serious pollution of the environment during the construction, its use has shown a downward trend. From a global perspective, the most widely used when push coal tar enamel and epoxy paint. The former has a strong anti-microbial corrosion, anti-plant root penetration, low water absorption, resistance to cathodic delamination, bonding wrapped solid strong on the wall, there are obvious advantages for use in the oil and gas pipeline The United States, Russia, in the large-scale use.

Pipeline coating the front surface pretreatment process improvements

The preservative quality depends on the level of the coated front surface pretreatment method selection. The traditional degreasing rust Law of time and labor pollution is difficult to guarantee quality. In recent years the tendency to use high temperature unglazed law degreasing, the pipe loading into specially furnace at 350 ~ 400 ℃ supplemented with ventilation, insulation 3 ~ 4 h, the oil burned guarantee degreasing quality.

Peening machinery instead of the traditional method of pickling. This method is the use of compressed air to carry steel shot (or sand) to form a high-speed flow of logistics strong impact on the steel surface through the nozzle of the gun to remove oil or oxide. It rust completely, but also improve the surface roughness, to increase the contact area of ​​the wall and the coating (about 20 times), and to improve coating bond strength, can be effectively prevented deep delamination.

Weled steel pipe specification, Standard and identification

Welded steel pipe (steel pipe manufactured with a weld) is a tubular product made out of flat plates, known as skelp, that are formed, bent and prepared for welding.