René Hermkens, Ernst van der Stok, Johannes de Bruin, Jeroen Weller
Papers # 2016 Berlin
The replacement of fossil fuels like natural gas by sustainable gases such as biogas and hydrogen can mitigate global warming. There has been some debate about the impact of sustainable gases on the materials used in the gas grid. An extensive study of the behaviour of PE, PVC, POM and rubber materials was therefore conducted. The most important conclusion from this study is that Dutch gas distribution grids will not be degraded by sustainable gas provided that the gas is dry.
To evaluate the effects of different types of renewable gases on PE and PVC piping systems in existing gas networks, Kiwa Technology participated in a Dutch research programme, Energy Delta Gas Research (EDGaR). The goal was to determine whether sustainable gases could degrade the PE and PVC pipes, rubber seals and polymeric couplers used in the Dutch gas distribution grid to an unacceptable extent.
A literature survey was first conducted to identify the chemical components in sustainable gases, the concentrations of the components, and the possible effects on the plastic pipe and coupler materials. It was found that some combinations of polymers and gas components could lead to environmental stress cracking (ESC) or an acceleration of known degradation processes.
Extensive exposure tests were then conducted with environmental stress cracking test rigs built and designed for this purpose to study combinations of plastic pipe materials gas components in realistic gas grid conditions such as concentrations and applied pressure. A total of 1300 polymeric samples were tested using twelve different gas compositions.
Finally, after two years of exposure, the environmental stress cracking samples were subjected to non-destructive and destructive testing.
This paper presents the results: rubber, PE and PVC pipes can withstand the impact of sustainable gases and POM is degraded by sustainable gases.