Chemo-physico-mechanical characteristics of corrosion products and their correlation with corrosion control in geothermal environments

Geothermal energy is a widely recognised renewable energy resource that provides reliable base load generation worldwide. The extraction of geothermal water for use as an energy source is of paramount importance and its usage is increasing worldwide. A problem in exploiting renewable geothermal energy sources is the production of acidic brine, that leads to excessive corrosion of production equipment.

This study will improve our fundamental understanding regarding the corrosion behaviour and the corrosion mechanism of carbon steel exposed to an artificial geothermal brine influenced by dissolved carbon dioxide under acidic conditions.

The focus of the work is directed towards characterising and understanding the chemical, physical and mechanical properties of corrosion products that form in geothermal systems, and relating these to the degree of protection provided to the underlying steel.

The project will involve the training and use of high temperature-high pressure systems (autoclaves) to replicate the harsh conditions encountered in geothermal systems. The project will involve use of electrochemical methods (namely, electrochemical impedance spectroscopy) to monitor the formation of corrosion products and determine their characteristics/influence on corrosion mechanisms in-situ, and in real time. This detailed in-situ analysis will be supported via a suite of ex-situ analytical methods (tomography, XRD, microscopy) to develop a comprehensive understanding of the corrosion product structure and its relationship to steel substrate protection.