Utilisation of Ultrasonic Testing to Monitor Corrosion of Absorber Tower

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Moomba plant is located in Cooper Basin, South Australia. This plant receives feed from 115 gas fields and 28 oil fields containing 536 gas producing wells and 177 oil producing wells, respectively. The central processing unit in Moomba consist of:

• Oil processing: crude stabilisation, crude/condensate storage and liquid export.

• Gas processing: inlet slug catchers, five Benfield CO2 removal plants, gas dehydration via molecular sieves, a natural gas liquids recovery plant, and pipeline compression.

• Generation of its own utilities (Register, 2010).

Due to high percentage of CO2, the feed is processed in CO2 Removal Plant prior undergone further processing in Liquid Recovery Plant in order to minimise corrosion. There are currently five active CO2 absorbers in the plant. Raw gas enters the absorber near the bottom of the vessel via a gas distributor. As the gas flows up the absorber, it contacts a counter-current flow of hot, lean potassium carbonate solution which will absorb CO2 from the raw gas (Santos, 2008).

Internal Corrosion of the Absorber

Raw gas that enters the absorber is very corrosive due to high containment of CO2 (about 17.5-21.5%) and presence of water (Santos, 2008). Material construction of the absorber is conventional carbon steel which is susceptible to CO2 corrosion. The attempt to mitigate the corrosion in the absorber has been taken place by pre-mixing the lean potassium carbonate with corrosion inhibitor.

Figure 1. Image taken during absorber internal inspection in 2012. It is shown that the absorber has undergone severe corrosion on the upper part section where wall loss of 3-4 mm has been recorded (Santos, 2012).

However, not all part of the absorber is protected. ...

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..., Adelaide: Santos.

Davies, A. & editor, 1998. Handbook of Condition Monitoring. 1st ed. London: Chapman and Hall.

Intico, 2006. #6 CO2 Absorber Thickness Survey Summary, s.l.: s.n.

Intico, 2007. CO2 Absorber No. 7 – Thickness Survey Data Analysis, s.l.: s.n.

Intico, 2008. Absorber Thickness Survey Summary Spreadsheet. s.l.:Intico.

Parsons, W., 2007. Santos RDAM Project - Moomba Plant, Perth: s.n.

Register, l., 2010. Santos Moomba Facility Formal Safety Assessment, s.l.: s.n.

Santos, 2008. Santos Moomba CO2 Train No. Operator Manual, s.l.: s.n.

Santos, 2012. Pressure Equipment Inspection Report - Maximo Asset No. 131147, Moomba: s.n.

Veritas, B., 2008. CO2 Absorbers 3, 4, 5, 6 and 7– Thickness Survey Data Analysis Summary, s.l.: Bureau Veritas.

Willcox, M. & Downes, G., 2003. A Brief Description of NDT Techniques. Hereford: Insight NDT Equipment Ltd.

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