Advanced Coated Steels for new demanding Biomass Firing environment having a high recycling behaviour and an improved service life

ended

In case of firing of opportunity fuels, common solutions applied to limit risks of tube failure caused by metal loss are lowering boiler operating conditions, therefore limiting conversion efficiency, or adopting advanced boiler materials, therefore rising boiler operating costs. Currently to increase the corrosion resistance of the boiler tubes, new steel grades are developed and this imply a possible long term application due to the stringent need of certification of the new materials for the relevant application. The application of protective coatings which increase the harsh environment durability of the tubes onto an existing steel (e.g. T22, T91) to increase the service life of the boiler tube, on the contrary, guarantees a short term application, due to the fact that the base material has well known performances. The coating treatments developed in BIOFIRE will enhance the environmental resistance of the existing fully qualified steels commonly used for boiler tubes for their use in power generation systems firing opportunity fuels by adopting low cost and easy handling thermochemical methods potentially applicable at industrial scale. Coating solutions, available for both inner (steam side oxidation) and outer (fireside corrosion) tubes, will lead an improvement of the boiler performance, both by reducing the outage time and maintenance expenditure resources. The goal of this project is the development of diffusion coating treatments, to be included in the industrial manufacturing process of steel components, in order to increase the life time of the tubes up to 2 times compared to un uncoated component and the prediction of the lifetime of the coated tubes. The project starts from a TRL5 (technology validated in relevant environment due to the experiences of the partner Flame Spray) and will arrive at TRL7 (system prototype demonstration in operational environment).