Impact of sustainable gases on joints used in gas distribution systems

Within the Dutch gas distribution system, joints are crucial to connect the individual pipes to form a closed system. Furthermore joints form a vulnerable group regarding the increase of malfunctioning due to gas composition changes. Joints can be divided into welded joints and couplers (mechanical).

Although some research has been performed in the past, the effect of sustainable gas on the installed welds and couplers is not yet fully understood. The necessary level of knowledge needed for the safe distribution and transportation of sustainable gases has not by far been reached yet. For example the heat affected zone of steel welded joints might degrade differently compared to the pipe material, due to locally different material structures.

Couplers are often used to connect pipes made out of different pipe materials. However in the gas distribution system polyvinylchloride pipes are also installed using couplers. In gas distribution, these couplers make use of rubber sealant rings to tighten the coupler joints. The influence of sustainable gases on the long time behaviour of this kind of mechanical coupler is still unknown and is therefore subject for study in this project.

Besides the direct influence of sustainable gases on the different types of joints, it is crucial to realize that sustainable gases may also have impact on the presently used maintenance, repair and extension methods for existing pipe networks. Components in these gases might penetrate into the pipe material and change the material properties which might lead to a poor welded joint quality. These influences will be investigated in this project.

Theme: From monogas to multigas
Leader: René Hermkens (Kiwa)
Partners: Kiwa, Enexis, Liander, Stedin 
Budget: 0.7 million euro

Participants

Johannes de Bruin (Kiwa)
Dirk Dijkstra (Rendo/NBN)
Wim van Erp (Stedin)
René Hermkens (Kiwa)
Jan Heerings (Kiwa)
Douwe Koops (Enexis)
Ben Lambregts (Liander)
Albert van der Molen (Stedin)
Peter Postma (Kiwa)
Wouter Rittel (Kiwa)
Ernst van der Stok (Kiwa)
Frans Scholten (Kiwa)

Communication

Hermkens, René. ‘New gases in existing grids.’ Gas without Frontiers: DVGW-EDGaR First Joint Conference, Apeldoorn, February 2013.