Final Report Summary - PROCOMO (Protective coatings with combined monitoring system to control process conditions in boilers) To gain efficient control and reliability of boilers, new methods and protections had to be applied. In the PROCOMO project a novel approach to both the monitoring of the boiler temperature as well as protecting the susceptible boiler construction was introduced. The main innovation was the combination of a protective coating and temperature monitoring optical fibre by developing a novel temperature monitoring protective coating. Hence less polluting and longlasting boilers, which were able to burn reliably fuels like waste and biomass, were achieved. The project objective was to improve the lifetime and reliability of co-combustion boilers by a monitoring coating, which enabled a better control of the burning process and increased the reliability of boiler components. The technical objectives of the project were: 1) development of a reliable, optimised optical fibre able to be embedded by using thermal spraying technique, and development of mechanical fibre lead-in / lead-out interface from hot section to the temperature monitoring device; 2) minimising hot corrosion and erosion rate by development of tailored protective coating including optimised metal matrix alloyed with suitable stabile hard particles; 3) minimising hot corrosion rate by decreasing porosity by sealing treatments and optimising of intermediate environmental barrier layers; 4) capability to recognise dramatic coating failures by using embedded optical fibres. Work performed in the project included data acquisition and experimental development work in the areas of optical fibres, power plants, protective coatings and distributed temperature sensing device. The tasks consisted of the following: - study of elevated temperature interaction between the sensor and different materials found in a protective coating; - survey of different fuel types and different boiler process conditions; - selection of fibre jacket material and integration techniques; - coating experiments and evaluation of the embedded fibre specimens; - selection and optimising of the coating materials and different thermal spraying methods; - testing the high temperature corrosion and erosion resistance of variety of coatings; - thermodynamic modelling of coating compositions; - raw material development and manufacturing for thermal spraying; - optimising the manufacturing parameters of thermal spraying; - Finite element (FE) software development for estimating stress variations from the measured temperature variations; and - determination of requirements for the connector in demanding conditions. The results were integrated and evaluated. The main achievements were: - manufacturing and testing excellent corrosion resistant coating materials for boiler conditions; - manufacturing of the connector for optical fibre leading for boiler use; - software development for temperature monitoring system. Embedding of the optical fibre with thermal spraying proved that the optical fibre was physically undamaged after the coating. However, the evaluation of the optical characteristics of the long fibre demonstrated weaknesses of the method. Other achievements were: coating material composition development and manufacturing of new raw material and optimised coating manufacturing, which led to good performance of the coatings in high temperature corrosion tests. The monitoring coating system, which was a novel combination of the protective coating system and the distributed fibre optical monitoring system, needed future development. It could be applied in the boiler components, such as superheaters, lining boundary, and economiser. The developed smart coating could possible prove applicable on other applications such as different types of tribological components (valves, bearings etc.), where information of the increased heat due to the increasing friction between the counterparts often caused significant damage. The other foreseen applications were protective coatings without optical fibre. The project objectives during the second project period were the following: - creating a method for integrating optical fibres into protective coatings in power plant boilers without mechanically damaging the fibres or destroying their sensing function; - tailoring raw material powders for coatings used in aggressive industrial environments; - development of protective coatings with superior corrosion and erosion resistance in different process conditions; - testing, evaluation and characterisation of the manufactured coatings; - development of an integration module for coupling the optical fibre, DTSmonitor and dedicated software for data collection; - fibre connector design and manufacturing; - technoeconomical evaluation of the developed protective monitoring coating system. The work that was carried out was divided into five work packages (WPs). WP 1: Science and base data Objectives of WP1 were to find out the current knowledge of the effects of fibre buffer and coating materials to fibre embedding, and the current knowledge of different service values and data of boiler conditions. Further, to define what type of fibre is best suited for this application. WP 2: Embedding of the optical fibre in the coating Objective of WP2 was to create a method for integrating optical fibres into protective coatings in power plant boilers without mechanically damaging the fibres or destroying their sensing function. WP 3: Protective coating development Objectives of WP3 were: - tailoring raw material powders for coatings used in aggressive industrial environments; - development of protective coating with superior corrosion resistance in different process conditions; and - evaluation and characterisation of manufactured coatings. WP 4: Interface development between optical fibre and DTS Objectives of WP4 were: the development of an integration module for coupling an optical fibre and DTSmonitor and dedicated software for data collection. Fibre connector development and design were also carried out. WP 5: Integration Objectives of WP5 were combining the knowledge and results obtained from the project, manufacturing of protective monitoring coating by thermal spray process and fibre embedding using optimal spray parameters, integration of dedicated software and connection system for coupling fibre and DTS device, system prototype integration and performance and technoeconomical validation. The protective monitoring coating can be used in different high temperature boiler applications, such as heat transfer surfaces in biomass boilers and waste incinerators for protecting the metal surfaces of components and for monitoring of the temperature, in order to control the combustion process. Benefits: longer lifetime of components, improved combustion process and improved maintenance and better planned shutdowns which results in economical gain for boiler user. The protective coating can be applied in high temperature applications for protection of metal components. Potential use besides biomass boilers and waste incinerators are other high temperature applications with harsh conditions. Benefits: longer lifetime of components which results in economical gain for boiler users. Modified coating materials can be used in demanding high temperature applications such as boiler coatings. Benefits: reliability for coating process and longer lifetime of components which results in economical gain for coating manufacturers and boiler users. Monitoring coating applied by thermal spraying can be used in different applications in large temperature range for monitoring the temperature. Benefits: Flexible fixing of optical fibre with thermal spray coating, which has tailored properties (such as low friction, high hardness) which results in optimal material surface with temperature measuring. Advanced FTR device for thermomechanical FEM calculation can be used in biomass boilers and waste incinerators for predicting the lifetime of metal components by measuring the temperature with optical fibre and calculating the stresses and strains in the material. Benefits: prediction of lifetime of components and better planned shutdowns which results in economical gain for and boiler users. Highstrength metalcoated silica fibres are excellent long life fibres for harsh environmental applications. Hermetically sealed metal-coated optical fibres have all the benefits of silicasilica fibres, such as increased mechanical strength, great fatigue resistance, large spectral range in transmittance and they also remain stable in corrosive chemicals that normally react to silica glass. Hermetically metal-coated optical fibres are the optimum candidate when used in high vacuum and harsh environmental conditions.
