Electrodialysis Membrane Technology applied to MEG reclamation – a case study

Abstract

At Beach Energy’s Otway Gas Plant (OGP) the mono-ethylene glycol (MEG) system salt concentration increased significantly following the commissioning of new subsea horizontally completed wells. Therefore, to de-risk future developments, which are anticipated to include similar wells, a salt removal strategy was implemented. The use of MEG for gas hydrate suppression in wet-raw gas subsea or onshore production pipelines is common across the oil and gas industry, with the MEG recycled using well-proven regeneration and/or reclamation technologies. The MEG extracts water that can contain residual salt and minerals, which over time accumulate in the MEG and can lead to several operational issues, including severe fouling in the MEG regeneration plant, production line blockages and production pipeline integrity concerns, such as accelerated corrosion. MEG reclamation is used to minimise salt accumulation and to date, the dominant technologies employed have been vacuum distillation or flash vaporisation. However, since early 2022, electrodialysis (ED) membrane technology has been deployed at the OGP in an effort to find a more cost-effective solution. The technology is proving a viable alternative to a traditional vacuum distillation reclaiming–regeneration process with energy savings of 17–28% for a hybrid ED-Regeneration process with significantly lower capital cost. This paper details the technical and operational challenges overcome to implement the ED reclamation technology in an industry with more stringent regulatory requirements when compared to typical ED applications (e.g. within the water treatment, pharmaceutical, and food and beverage industries), as well as present the main system performance outcomes following 6 months of operation.