Why isn’t internal anti-corrosion treatment applied to gas pipelines?
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In the gas pipelines I’ve worked on, I’ve never seen any internal anti-corrosion treatment; 3PE coating is used on the outside, but the inside isn’t treated in any way. I read in previous posts that internal anti-corrosion treatment is necessary for crude oil pipelines due to the corrosive properties of crude oil. Is it because the components in natural gas pipelines aren’t corrosive gases that such treatment isn’t required? Please let those who know inform me, young man.
After emerging from the gas field, natural gas must undergo multiple filtration processes in purification plants. By the time it reaches the long-distance pipelines, only a small amount of hydrogen sulfide remains. Moreover, the inner walls of these pipelines are usually coated with anti-corrosion layers, so this does not pose a significant risk of corrosion; therefore, no additional anti-corrosion treatment is generally required. Additionally, long-distance pipelines are cleaned regularly to remove impurities from within them, which further prevents conditions that could lead to corrosion.
After coming out of the gas wells, natural gas is filtered, deacidified, and dehydrated at purification plants; in some cases, mercury removal is also carried out. Once it meets the required standards, it is sent into the gas transmission network. The levels of carbon dioxide, hydrogen sulfide, and water in it are already low enough, and there is no oxygen present; therefore, the natural gas coming from the purification plant that meets the standards does not require internal anti-corrosion treatment.