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

地热能是一种公认的可再生能源，可在全球范围内提供可靠的基本负荷发电。提取地热水作为一种能源至关重要，其使用量在全世界范围内都在增加。开发可再生地热能源的一个问题是生产酸性卤水，这会导致生产设备的过度腐蚀。这项研究将加深我们对碳钢在酸性条件下受溶解二氧化碳影响的人造地热卤水中的腐蚀行为和腐蚀机理的基本认识。这项工作的重点是确定和了解地热系统中形成的腐蚀产物的化学、物理和机械特性，并将这些特性与为底层钢提供的保护程度联系起来。该项目将涉及培训和使用高温-高压系统(高压灭菌器)，以复制地热系统中遇到的恶劣条件。该项目将涉及使用电化学方法(即电化学阻抗谱)监测腐蚀产物的形成，并在现场和实时确定其特征/对腐蚀机制的影响。这种详细的现场分析将通过一套非现场分析方法(断层扫描、X射线衍射仪、显微镜)来支持，以全面了解腐蚀产物的结构及其与钢衬底保护的关系。

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.