Novel Plastic Composite Pipe Prevents Diffusion

16 July 2021

With storage capacities of around six billion cubic meters of natural gas, RAG Austria AG is the largest gas and thus energy storage company in Austria. Delivered gas is temporarily stored in depleted natural gas reservoirs. Since natural gas absorbs moisture in the reservoir, it is dried and cleaned after extraction. This produces mine water, which is pumped back into the gas storage facility. Salts and hydrocarbons dissolved in the water must not be released into the environment under any circum-stances. AGRU therefore supplied a new type of diffusion-tight piping system, the AGRU Sureline IV barrier pipe. The expert installation was carried out by RTi Austria GmbH, which specializes in the trenchless installation of pipelines. 

During the extraction and drying of the temporarily stored gas, mine water is produced that originates from the primordial sea and is pumped back into the deposit. RAG Austria AG pays attention to the highest environmental compatibility in all work processes and was looking for a pipeline system that effectively pre-vents the diffusion of hydrocarbons from the mine water. A steel pipeline installed a few years ago corroded due to the high salt content and had to be replaced. Conventional PE piping systems are corrosion-free, but in this case they do not offer sufficient protection against permeation of hydrocarbons through the pipe wall. Therefore, the diffusion-tight AGRU Sureline IV barrier pipe from AGRU Kunststofftechnik GmbH was chosen for the new reservoir pipeline. The fully pressure-resistant plastic composite pipe was specially developed for the transport of contaminated wastewater or chemicals through ecologically sensitive areas. It can also be used to transport drinking water or ultra-pure water through contaminated soils.  

In order to continuously monitor the safer transport of the aggressive primordial sea water, the engineers at RAG Austria AG decided on a double-piping system with integrated leak detection. For this purpose, the media-carrying Sureline IV barrier pipe was drawn into a larger-dimensioned Sureline III pipe, which serves as a protective outer pipe for maximum safety. For a clean annular space, the outside of the Sureline IV barrier pipe was cleaned with hot steam during the pulling-in process. The remaining annular gap between the two pipes is intended to act as a pressure-resistant containment space to prevent media leakage in the event of a leak. Since a detection system is installed at the end of the pipe in the pump house to fully monitor the annular space, sensors immediately report any leakage. Both the media pipe and the protective pipe can withstand full pressure in this double pipe. With the exception of the missing barrier layer, the protective pipe is identical in construction to the media pipe. This means that even in the unlikely event of a leak, the strictest environmental protection regulations are reliably complied with. 

Courtesy of AGRU Kunststofftechnik.