How to select the city buried gas pipeline outside anticorrosive coating

The selection problem of the city buried gas pipeline outside anticorrosive coating:(1) There is no universal type anticorrosive coating, and there is no absolute useless coating material. At present, there are many kinds of pipeline coating materials at home and abroad, are also applied in practice. All kinds of anti-corrosion material has the characteristics of itself and the applicable condition. There is neither universal anti-corrosion materials which can be used in various environmental conditions and project, nor the problem that some kind of anticorrosive coating is absolutely useless. For a specific pipeline anticorrosive engineering, only according to various aspects such as the pipeline operation condition, soil condition, construction environment and technology, pipeline design life, environment protection and economic rationality and so on to conduct a comprehensive and balanced consideration, can we choose out the practical anticorrosive coating material.(2) The technical and economic feasibility is the basic starting point to choose the anticorrosive coating. Choose which kind of anticorrosion coating for a pipeline, the main factor is considering the technical feasibility. To consider both meeting the requirements of pipeline operation condition and construction process, at the same time should also be allowed under the condition of the construction environment, make an economic comparison of the various coating with the same anticorrosive effect to choose the coating meeting the requirements of the technical performance and also economic. Technical feasibility, therefore, is the basic starting point, and economic expense is also an important factor to measure and decide the anticorrosive layer.(3) the anticorrosive coating selection of evaluation methods Independent laboratory evaluation method is widely used when choosing coating abroad, for a variety of anti-corrosion layer to make a comprehensive performance evaluation and as a basis.

Here are some ideas about choosing anti-corrosion materials of ERW steel pipe:A, NOVA and Raychem company through test and research for many years put forward the following advice to choose anti-corrosion layer: "in a stone or river crossing area, choose high strength fusion bonded epoxy, extrusion polyethylene anticorrosive layer or double, three layer PE anticorrosive coating; in the chlorine saline soil area, select fusion bonded epoxy, extrusion polyethylene and coal tar enamel, resistance to chlorine ion anticorrosive coating; in the swamp area, choose anticorrosive layers with long-term water resistant and resistant to chemicals; in carbonate soil, select asphalt and polyethylene tape with carbonate ions anticorrosive resistance; in the case of high medium temperature, preferable fusion bonded epoxy."B, the advice of American corrosion engineers society is:even if abandoning the economic into consideration, it is impossible to order all kinds of anticorrosive coating, must choose according to the specific engineering condition of concrete.