Several methods can be used for anti-corrosion of urban sewage buried pipelines:
1. Petroleum bitumen-glass fiber cloth coating
This kind of anti-corrosion method was used more in oil pipelines, but it is now being eliminated. Its advantages are wide sources of raw materials and low cost. The disadvantage is that it is not resistant to bacterial corrosion, poor physical properties, and the harsh construction environment.
2. Chlorosulfonated polyethylene coating-glass fiber cloth coating layer
This method has a good anti-corrosion effect, a wide construction temperature range, and can be used in conjunction with cathodic protection. However, surface treatment requirements are high, the coating is thinner, and the mechanical strength is low. It has been used in the water diversion project of the Huangpu River in Shanghai.
3. Epoxy coal tar pitch coating-glass fiber cloth coating layer
This method has good chemical and electrochemical corrosion resistance, bacterial corrosion resistance, high mechanical strength, and a wide application range. Can be used in conjunction with cathodic protection. The disadvantage is that it cannot be constructed at low temperatures (below 0°C) and requires high surface treatment. At present, it widely uses in urban sewage treatment projects.
4. Polyethylene insulating tape is coated with an anti-corrosion layer
This method is convenient to construct, easy to repair and has good anti-corrosion performance. However, the mechanical strength is low and the cathodic disbanding resistance is poor, so it is not suitable for application with cathodic protection, and the sealing performance on special-shaped parts is poor. There are many applications in oil and natural gas pipelines.
5. Fusion Bonded Epoxy Coating
The advantages of fusion bonded epoxy coating are good corrosion resistance, high mechanical strength, high construction efficiency, and good coordination with cathodic protection. However, coating construction should be carried out in the workshop, and other methods (such as liquid epoxy resin) should be used for on-site repair. Fusion-bonded epoxy coatings are more common in foreign countries.
6. Cathodic protection
It is an advanced anti-corrosion application technology with good anti-corrosion effect, long and predictable life, and can monitor the operation and corrosion status of pipelines. Must be used with anti-corrosion coating. Industrial water pipelines and long-distance pipelines are used in many applications, and the effect is good.
Post time: Sep-24-2020