The drying of pipelines and installations needs to be carried out for a number of reasons, often during operation and after hydro testing.

A.Hak Pipeline Services offer a number of flexible drying solutions that can be adapted to suit the specific needs of the client, the situation and the technical possibilities.

Often it is through a combination of our drying techniques that we can provide the safest, fasted and most economical solution. Our technical expertise, combined with the best available equipment and technology in-house, means we will find the best drying solution for you.

All drying operations are controlled with a scala of different types of dew point testers. Regardless of whether the situation is mobile, atmospheric, under pressure or under vacuum, we will always be able to measure the current pressure and/or atmospheric dew point in a system at any moment.

The goal of swabbing is to enlarge the evaporation area of present water by spreading it over the pipe wall. This enables a large contact area between the water and the drying media. Several types of pigs are used for this method.

Super dry compressed air
This is the most commonly used method to dry a pipeline. Using our sophisticated, dew point controlled desiccant dryers, compressed air is dried up to dew points of -60°C and blown into the pipeline with a high flow. In combination with swabbing pigs, pipelines can be dried to proven dew points of -40°C.

Super dry chilled air
Another method of drying with super dry air is to chill the air with chilling units. Instead of using compressed air, the chilled air is moved into the pipeline with ventilators. However, since the flow is high but the pressure is low, combining this with swabbing pigs is a not always possible.

Super dry hot air
If time is a major factor, we can use heaters to heat the compressed dry air to raise the temperature in the system. Due to this higher system temperature, evaporation of water will take place more quickly and easily.

Vacuum drying
Vacuum drying is a straightforward technique whereby, the lower the maintainable pressure in a system, the lower the dew point. The only other variable in the calculation is temperature, making it a very controllable method of drying. This is a particularly effective solution for complex systems, for systems where a proper flow cannot be achieved, non-piggable systems, and for systems with localized, large quantities of water.

Nitrogen itself is not hygroscopic, but due to the low temperature requirements for fabrication, it is a very dry product, which can help effectively in drying operations. It is especially useful for pipelines and systems where dew points below -40°C are required. In order to achieve dew points up to -60°C, we need to replace the air with nitrogen. Another major advantage of our nitrogen pumpers is the possibility to heat the nitrogen. Then, just as with hot air drying to raise the temperature, we can significantly speed up the evaporation process. The amount of heating energy injected with heated nitrogen is much higher than heated hot air, making heated nitrogen more effective.

Methyl Ethyl Glycol (MEG) batching
This process uses the hygroscopic effect of MEG to dry the pipeline or installation. The calculated batch of MEG is propelled through the pipeline using natural gas, nitrogen, dry air or other product. The pipe wall is completely dry after the batch has passed, so any risk of water freezing or hydrating of product is not present.

Drying a 48" pipeline to dewpoint -40°C.

A.Hak Industrial Services B.V.
Pipeline Services
Beukvenne 3
8112 BA Nieuw-Heeten
The Netherlands
T +31 (0)572 342 601

Our global locations