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- Carbon dioxide (1)
- Carbon steel (1)
- Corrosion (1)
- Electrochemical characterization (1)
- High alloy steel (1)
- Localized corrosion (1)
- Nickel based alloys (1)
- Renewables (1)
- Solar energy (1)
- UNS N06600 (1)
Condensates from the gas stream in simulated CO2 transport pipelines have been identified during the experiments in the laboratory. Because of their acidic origin the corrosion resistance of pipeline steels used for CCS (carbon capture and storage) technology might be limited. Over the last years it has become clear that the amount of water and acid building constituents in the CO2 stream has to be controlled very well. In this work, condensates formed in experiments using gaseous CO2 containing high amounts of water, NO2 and SO2 were analyzed, replicated, and used for extensive electrochemical experiments. These highly acidic condensates were enriched with CO2 and then applied to characteristic steels planned to use in the CCS transport chain. Even high alloy steels are susceptible to localized corrosion under these conditions. The results implicate that condensation of aggressive acid droplets has to be avoided or the locations where condensation takes place have to be controlled extensively.
Within the last years the use of feasible alternative energy sources has risen and is going to replace fossil resources more and more. Nevertheless, service conditions in solar facilities are due to the chemical composition of heat transmission media and temperatures, in many cases, extreme in terms of corrosion. Since the construction of power plants shall be economical with maximum life service, materials selection based on preliminary material qualification is essential to guarantee a secure and reliable operation of those facilities.
The materials selection depends on the operation temperature of a power plant on the chemical composition of the transmission fluid used. In high corrosive environments Ni-based alloys are often used as an all-round solution for the construction of corrosion resistant parts, because of their good corrosion properties. However, there might be limits for their use regarding their corrosion behavior, with which this contribution deals.
Experiences from the electrochemical characterization of materials in aqueous solutions are transferred to molten salts, providing a good addition to common exposure tests at temperatures from 450 0C to 600 0C.
By means of electrochemical measurements and exposure tests the suitability of high alloyed materials in molten nitrate salt (60 % NaNO3/40 % KNO3) can be characterized. The method was verified on different Ni-based alloys (UNS N08810, UNS N06600) and Titanium (UNS R50250).