长输管道防腐层的选择

Selection of corrosion protective coatings for long distance pipeline

综述了目前长输管道防腐层现状及常用防腐层材料的特点。从管道周围介质的腐蚀性、环境及防腐层施工等方面,分析了外界条件与防腐层失效的关系。防腐层失效的形式主要有:防腐层的剥离、破裂、穿孔及变形。分析了导致防腐层失效的原因,指出产生剥离的原因与防腐层材料性质、钢管表面的处理、阴极保护电流有关;而破裂与土壤应力、外力及材料老化有关;穿孔则是施工不当或外力造成的。介绍并评价了国内外常用的几种防腐层的性能特点,提出长输管道防腐层的选择应根据具体情况,从下述四个方面进行论证比较:外界条件;管道工作寿命、工程重要性及对管道维修要求;防腐层质量;费用。根据管道实际需要,采用相应的性能优异及合理费用的防腐层才是最佳方案。

Summarizes present situation on corrosion protective coatings for long distance pipeline and characteristics of commonly used coating materials. Analyzes relations from external condition with coatings failed in the aspects of medium's corrosiveness around pipeline, environment and coating construction. Types of failed coatings are mainly: coating disbonding, rupture, puncture and distortion. Analyzes reasons of coating failure and points out that reason of disbonding relates closely with the quality of coating material, steel pipe's surface treatment and cathodic protection current; the rupture relates with soil stress, external force and material's aging; and puncture is resulted from incorrect construction or external force. Introduces and evaluates properties and characteristics of some commonly used coatings domestically and point out that coatings selected for long distance pipeline shall be proved and compared in the following four aspects based on concrete conditions: external condition, pipeline work span, engineering significance and pipeline maintenance requirement, coating quality and cost. Optimum plan is to use the coatings of relatively good properties and reasonable cost in light of pipeline's actual requirements.