Predicting the lifespan of metallic left-overs in the ocean

Wednesday, 26 August 2020

Steel pipes, sunken ships, discarded weaponry and other decommissioned infrastructure corroding on the ocean floor are the subject of a new research project at the University of Newcastle.

Professor Robert Melchers
Professor Robert Melchers is developing a tool to predict corrosion rates of decommissioned metallic infrastructure in the ocean

Lead Researcher, University of Newcastle’s Professor Rob Melchers, said it was common practice to leave pipes and other disused steel assets to corrode at the bottom of the ocean where environmental conditions such as water temperature, salinity and acidity all influenced the rate of corrosion of metals.

“Our initial focus is to be able to predict, with greater accuracy, how long it will take decommissioned oil and gas pipes off Australian coasts to corrode,” said Professor Melchers.

“Some of these objects may still contain contaminants that could eventually leak into the environment, so tools for predicting when this is likely to happen are important.”

The project, which is funded by a grant from National Energy Resources Australia (NERA) and the National Decommissioning Research Initiative (NRDI), will review historical data to develop a tool for predicting the lifespan and corrosion behaviour of decommissioned metallic infrastructure in the ocean.

“Once we develop such a predictive tool, it will have applications for similar situations globally, for example, in the North Sea where there is an abundance of corroding oil mining infrastructure and even discarded items from World Wars I and II.”

In addition to an extensive review of existing research, Professor Melchers and research partner Professor Mike Tan from Deakin University will perform corrosion monitoring experiments in a simulated marine environment. By mimicking marine conditions in the laboratory, factors influencing corrosion can be controlled and corresponding corrosion rates measured.

Of particular interest to the research team is the influence of microorganisms and biofouling on corrosion of metal structures.

“Our experience shows that environmental conditions, including pollution levels, influence the growth of bacteria in the water which in turn impacts the rate of corrosion,” said Professor Melchers.

“Our most immediate concern is for oil and gas being released from corroding pipes, but there are still places in the world that have unexploded weapons beneath the sea. The more we learn about rates of corrosion under different conditions, the more accurate our assessment of risks such as leaking or even exploding.”

University of Newcastle Deputy Vice-Chancellor (Research & Innovation), Professor Janet Nelson, said that this project was an excellent example of how universities and industry bodies can come together to problem solve.

“Finding a solution to a national and global sustainability issue like the management of marine corrosion calls for cooperation and sharing of expertise between academic and industry partners. Communities expect universites to step up and help with real problems, and I’m thrilled to see the outcomes of this research and the impact it will have on the management of marine infrastructure in the future,” Professor Nelson said.

This research project follows the recent Australian Research Council Linkage grant awarded to Professor Melchers and his team to develop a computer modelling system that simulates the deterioration and corrosion of ocean-going vessels.

Professor Melchers is with the University of Newcastle’s Centre for Infrastructure Performance and Reliability in the Faculty of Science.

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