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1373 |
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Tuesday, June 03, 2008, Room 05 11:50 AM Case Studies and Further Applications 1 Showing the broad variety of thermal spraying in different examples, special processes and also specialized materials apart from standard coatings offer new possibilities and also new markets |
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Systematic approach to design new protective coatings to a biofuel boiler plant |
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Erja Turunen* / VTT, Technical Research Centre of Finland, Finland Tommi Varis / VTT, Technical Research Centre of Finland, Finland Satu Tuurna/ VTT, Technical Research Centre of Finland, Finland Karri Penttilä/ VTT, Technical Research Centre of Finland, Finland |
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The use of biofuels in power plant boilers causes challenges for material performance. The conditions in biofuel fired boilers consist of deposit formation on superheater tubes. Deposits containing e.g. potassium, sulphur, calcium, sodium, and chlorine can cause severe corrosion problems for conventional metal alloys. Thermal sprayed coatings can offer one solution for improved protection of power plant components such as superheaters and waterwalls. In this paper systematic approach on design of protective coatings is presented. It includes thermodynamic modelling of process conditions, optimisation of thermal spray process, coating structure and validation of coating performance in laboratory scale simulation tests as well as in real components in biomass boiler plant. Based on the results from the first round, which was performed for commercially available materials, the second round including material composition design is introduced. Paper discusses usability of presented systematic approach and gives microstructural, mechanical and corrosion resistance analysis for produced coatings related to the estimated life time prediction. Studied materials are iron and nickel based HVOF and arc sprayed coatings |