Martyn Cooper, Lead Integrity Engineer, Santos Ltd
John Flecher, Senior Integrity Engineer, AMIS Integrity Ltd
The Moomba processing plant in central Australia processes raw gas with 20% CO2 down to sales gas specifications. This is completed through CO2 removal trains using the UOP Benfield process (a recirculated hot potassium carbonate solution). The plant commenced processing natural gas in 1969 and was expanded in the 1970s and 80s to seven trains with a combined throughput of 600 TJ/d.
Corrosion in the CO2 trains, and more specifically in the top of the CO2 absorbers was first noticed in the 1980s. Over time this led to one of the absorber towers requiring refurbishment. A project was initiated in 2006 to re-life this Absorber by replacing metal lost to corrosion and at the same time upgrade the metallurgy to provide corrosion protection. The refurbishment needed to be completed during a routine plant shutdown and fit within the existing maintenance window.