| Abstract: |
One of the major issues being faced globally these days is climate change. CO2 is the most predominant greenhouse gas, with almost 40% of its emissions coming from the fossil-fuelled power plants, the worlds main source of energy. One way to utilise fossil fuels whilst minimising the adverse impact upon the environment is carbon dioxide capture and storage (CCS). CCS systems use carbon steel pipelines to transport carbon dioxide, because of their low cost and low corrosion rate under dry CO2 environments. However, sometimes the presence of water is unavoidable, resulting in the formation of a corrosive, acidic solution. In order to mitigate corrosion, when drying of CO2 is not feasible, corrosion resistant alloys (CRAs) such as stainless steel are used. But since the cost of the pipelines made from CRAs is relatively high, new methods of corrosion mitigation are sought. One of the potential methods, that can be used, is thermally sprayed aluminium (TSA), therefore in this paper its suitability to mitigate corrosion in CO2 environments was investigated. This was accomplished by conducting a 30-day test during which carbon steel specimens sprayed with aluminium were immersed in deionised water at ambient temperature in 1barg CO2 and the acidity (pH), potential and corrosion rate of TSA were monitored. Corrosion rates of TSA were determined with the use of two methods: an analytical technique based on analysis of amount of dissolved ions and weight loss analysis. The results showed that the corrosion rate of TSA in CO2 environment is no less than 0.02 mm/year. Moreover, potential measurements of TSA and steel in deionised water saturated with CO2 revealed that polarity reversal phenomenon takes place.
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