长输天然气管道外防腐涂层选择

Selection of External Coatings for Long Distance Gas Pipeline

外防腐涂层是埋地钢质管道主要防腐手段 ,阴极保护是涂层防腐的补充手段。为保证长输管道在预期的使用寿命内不产生由于外腐蚀而引起功能损失。选用性能高、寿命长但一次费用高的涂层比选用性能低、寿命短、一次费用低的涂层对长寿命的工程更经济。在涂层技术经济分析中还必须考虑人文条件 ,人文条件是指施工单位的质量意识和管道所经地区居民的素质。综合各种因素 ,对西气东输这类大口径、长距离、使用寿命长的输气管道 ,现阶段首选三层 PE;随着人员素质的提高 ,条件允许的地区应大力发展熔结环氧粉末涂层 ;石油沥青只能用于预期使用寿命不长的管道 ;煤焦油瓷漆适用管径不大或预期使用寿命不长、人口密度不大的管道工程。

External corrosion coating is a main corrosion prevention measure of buried steel pipeline,with cathodic protection being complementary.To prevent long distance transmission pipeline from producing functional loss due to external corrosion during their expected operating life,coatings with high performance,long life and high primary investment are more economical than coatings with low performance,short life and low primary investment in regard to long operating life engineering. In addition,construction guality and person diathesis and so on are important effecting factors,and shall be considered in selection of coatings.For West East Gas Pipeline with large diameter,long distance and long operating life,in the first,3 lay PE is recommended,fusion bonded epoxy powder coating shall be extensively adopted in those suitable areas;asphalt coating is only used on the gas pipeline with a short expected operating life.