Research on the Corrosion Problem of Carrier Pipe in the Casing Pipe

The different protecting methods for the carrier pipes prevented with casing pipes from corroding during 1970s~1990s in the northeast China oil pipeline are respectively introduced. By analyzing the several corrosion cases of the carrier pipe with casing pipe occured in the pipeline during different periods, the author considers that the steel casing pipe remains the effective means to protect the carrier pipe for the carrier pipe located at the crossing points (high way, railway, river, and expressway). As for the filling materials used within the gap of the two pipes, the melting asphalt surpasses other materials, such as polyurethane foam and rock wool, which can effectively prevent the carrier pipe from corroding. However, the protecting effect of this material needs to be further determined on site.