PUF pipes application in the gas industry
Interestingly, according to the current estimates, 50-60% of losses in the gas industry occur due to premature wear of pipelines that are operated in harsh climatic conditions.
Thermal insulation of gas pipes with polyurethane foam (PUF) is a relatively novel method of achieving a higher service life of pipelines and preventing other related issues when transporting gas over long distances.
In terms of design, PUF gas pipes are different from their standard versions. The distinguishing feature is the tracer pipe or heating cable in contact with the main pipe. These elements are designed to create the so-called “skin effect”, which consists in releasing heat for the subsequent heating of the main pipe. This approach allows to maintain the optimum temperature in the entire gas pipeline regardless of its length and to avoid the increase of gas viscosity during its transportation.
Above-ground and underground types of gas pipelines
Polyurethane foam, as opposed to other thermal insulating materials, can be used to lay above-ground, underground and submerged pipelines. The only difference is the protective shell of the pipe. While with underground and submerged gas pipelines the top protective layer is made of waterproof polyethylene, galvanized steel is used for above-ground pipes, providing reliable protection of the pipe inside structure from UV radiation.
To provide the highest level of protection for the gas pipeline in a wet environment, the main pipe is additionally covered with a corrosion-resistant layer and tightly sealed. The availability of the rapid remote control system help monitor the pipeline operation and quickly locate the failure. This approach allows to detect the pipe damage on the spot and promptly repair it to prevent an accident from developing.
Comparison of PUF characteristics with other insulating materials
Besides polyurethane foam, other thermal insulation materials can be used in the construction of gas pipelines; their performance characteristics are given below.
Table of comparison:
|
PUF | Highly reinforced insulation | Liquid insulation* | Foam rubber |
---|---|---|---|---|
Thermal conductivity, W/(m·К) | 0,033 |
0,037 |
0.0358-0.739 depending on number of layers | 0,036 |
Density, kg/m3 | 80-100 | До 200 | 0,6-0,7 in liquid state | 40-80 |
Service life, years | > 30 | > 30 | > 15 | 10-20 |
Strength, MPa | 0,3 | 0,3 | - | - |
Material structure | Closed pores | Closed pores | Hollow | Porous |
Heat resistance | Moderately flammable | Moderately flammable | - | Weakly flammable |
RRCS | Yes | No | No | No |
Benefits of PUF thermal insulation
At the moment, there are almost zero alternatives to using pipes in polyurethane foam thermal insulation in the construction of gas pipelines of any length. PUF pipes perform excellently both under southern, and northern climate conditions and guarantee trouble-free operation for many decades without the need of overhaul.
Among the primary benefits of PUF also are:
- Full protection against corrosion and corruption of the steel pipe
- Immunity to alkaline and acidic soils. No need to use electrochemical protection
- Pipelines can be laid under water
- Extended service life even under continuous load
- Suitable for installation of the rapid remote control system
- Environmental friendliness;
- Fast ROI