Coil coating is a continuous process for providing coating to a metal strip. In 2017, a total area of 1.37 billion m² of aluminium and steel was coated with 219 kt of paint in Europe, representing one third of the worldwide production. The coil coated products are mainly used in the construction market as building envelope. Consumers encounter coil coated products in everyday life for example as casing in a variety of size from fridges, washing machines to toasters and wireless speakers. In the coil coating process, a paint, mainly consisting of pigments, chemical crosslinkers and solvents, is applied to a metal strip. In a following step the paint is dried while the solvents evaporate. Afterwards, the paint is cured up to a certain temperature where the crosslinkers increase the adhesion between pigments and metal strip. In the conventional process the required heat is provided through convective heat transfer using hot air. In order to prevent the creation of an explosive atmosphere in the process, operation at a solvent concentration below the lower explosion limit by using an excess amount of air is inevitable. Prevention of VOC emission entails either recovery or thermal decomposition of the solvents, which can be stated as being technically complex and expensive due to the high dilution of the solvents.
In the ECCO project the proof of concept of a novel curing oven will be performed in a pilot scale coil coating line. In ECCO, the curing oven is operated at elevated solvent concentration which allows the direct utilization of solvents as a fuel for heat generation. Therefore, the oven system is separated in two sections: The radiant burner section, where intense radiation in the IR-spectrum is emitted at high temperatures resulting from combustion inside of a ceramic porous structure, and the curing oven section which is operated over the upper explosion limit or, in other words, below a critical oxygen concentration. The prevention of a thermal decomposition of the solvent loaded atmosphere at high temperatures is ensured through separation of the two oven sections by an IR-transmissive material. Starting from previous activities at TRL 4, an interdisciplinary approach is foreseen, based on advanced-materials, combustion technology and prediction tools for system design/optimization, with active participation of key industrial stakeholders, to bring this technology to TRL 6 and realize a prototype curing oven at industrially relevant size and environment. ECCO proposes an oven concept which leads to a drastically reduced size and increased energy efficiency as we as well a higher production flexibility due to a fuel-flexible, modular and potentially energetically self-sustainable process. In comparison to existing conventional convective curing systems, ECCO presents a less energy demanding, environment-friendly and economical technical curing oven concept.
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The project ECCO proposes a novel solution for the curing oven operation, which can not only drastically increase the compactness and energetic efficiency of the system, but leads to an increased production flexibility due to a fuel-flexible, modular and potentially energetically self-sustainable process, which can even provide an energy surplus to be used in other parts of the coil coating process or nearby facilities. Additionally, it offers the potential for solvent recovery and reuse.
The main idea is to heat the metal strip by IR-radiation and operate the curing oven well above the Upper Explosive Limit (UEL), thus, performing the drying and curing process in an atmosphere mainly consisting of the solvent vapours, which are recirculated in order to provide also a minor supporting convective flux within the oven. The heat source for the drying/curing process is high intensity IR-radiation provided by IR radiant burners. As a result heat fluxes to the coated metal strip are increased compared to conventional convective ovens and the necessary curing temperatures at the surface of the strip can be reached more than 4.5 times faster resulting to correspondingly reduced oven sizes (linear dependency concerning the length) and/or increased line speeds.
Overall objectives are:
The core R&D activities are divided in two progressive phases with increasing TRL levels from 4 (technology validated in lab) to 6 (technology demonstrated in relevant environment) and are accompanied by other complementary activities (coordination and management, dissemination and communication, LCA, KPIs and market study). These activities can be briefly summarized in the following points:
An illustration of the above mentioned activities and the partners involved in it is shown in the diagram below:
The ECCO project brings together 12 partners (4 universities, 2 private research centers, 3 SMEs and 3 large enterprises):
1 - Karlsruhe Institute of Technology: The group of Prof. Trimis has a long-term cooperation experience with most of the ECCO partners (ERIC, SUPSI, ENGICER, NTUA, IST, GOGAS) in the framework of several previous EU and national german projects (e.g. CEREXPRO, HELMETH, FC-DISTRICT, FLAMESOFC, ITROLL), and in some of these also as coordinator. This is an important asset for the effectiveness of the ECCO consortium. At the same time, the KIT group brings along their scientific expertise in the field of combustion fundamentals and porous burner development. The available experimental facilities are of particular relevance for the needs of ECCO as they include a series of model burners (e.g. heat flux burner, McKenna burner, counter flow burner, inverse diffusion flame burner, combustion bomb) together with the appropriate equipment for applying wide ranges of operating conditions, and these will be used for the characterization of solvent combustion properties. At KIT there is state-of-the-art combustion diagnostic equipment (LDA, LIF, GC, SMPS) that will be used for ECCO. Furthermore, the group is very well equipped in terms of modelling and numerical simulations with in-house developed CFD packages, commercial CFD packages, the necessary computing cluster. These tools will be used for the optimization of the radiant porous burners in ECCO.
2 - GoGaS Goch GmbH & Co. KG: GoGaS is an SME with vast experience (since 1958) in project management, construction and manufacturing of drying plants for different industrial branches (e.g. paper, textiles, steel, aluminium, plastic). GoGaS supplies infrared systems for drying one or both sides of coated steel strips based on the application of porous burners. As experts in the field, GoGaS has a key role in ECCO as responsible partner for the complete design and fabrication of the curing furnace section.
3 - Globus SRL: Globus (established in 1995, while the team had already over twenty years of experience in the sector) is an engineering company specialized in design, construction and commissioning of plants for the continuous treatment of metal strips all over the world. They will supply the ECCO pilot coil coating line ensuring the conformity of the experimental coating process with industrial processes.
4 - AkzoNobel Industrial Coatings AB: AkzoNobel is a leading company worldwide in the field of paints and coatings and a major producer of specialty chemicals. Calling on centuries of expertise, the company supplies industries and consumers worldwide with innovative products and in the ECCO project they will provide their coatings know-how and support with formulation information regarding management of the volatile level and composition.
5 - Scuola Universitaria Professionale della Svizzera Italiana (SUPSI): The group of Prof. Ortona in SUPSI will lead the development of new ceramic-metallic materials in the ECCO project, with optimized high-temperature corrosion resistance and radiation output for application in the radiant porous burners. Prof. Ortona is the Head of the Hybrid Materials laboratory at MEMTI (Mechanical Engineering and Materials Technology Institute) and full professor at SUPSI and is an expert in process engineering of polymer matrix composites, of carbide ceramics and their composites since 2001 (60 papers and 5 patents). SUPSI is fully equipped for material characterization and for testing additive manufacturing processes.
6 - Engicer SA: EngiCer SA is about cellular ceramics and their engineering, specialized in foams and lattices. The company is a spin-off of Erbicol SA formed in 2013 as a result of a continuous growth in the sector. Despite the company is rather young, its technology, experience and people are based on an almost 20 years history. Building on previous work, EngiCer will continue the development and optimization of regular porous ceramic structures for burners, in terms of materials and manufacturing techniques. EngiCer owns a production line for the manufacturing of ceramic foams and lattices that will be made available for the needs of the ECCO project.
7 - European Research Institute of Catalysis A.I.S.B.L. (ERIC): The “European Research Institute of Catalysis A.I.S.B.L.”, abbreviated “ERIC”, is an international non-profit association (Virtual Institute) with legal personality (registered in the Belgian 'Crossroad Bank for Enterprises') gathering together 15 major European Institutions with large interest on catalysis related activities. The research unit (RU) involved in this project is Politecnico di Torino (POLITO), Italy, which is Ordinary Member of ERIC. ERIC, through POLITO, will develop photocatalysts for the preparation of coated IR-transparent windows with self-cleaning properties and will also assess material properties, performance and degradation of catalytic coated quartz. POLITO is fully equipped (GC/MSD, micro-GC equipment, FT-IR, ND-IR and UV-vis analysers, XRD, UV-Vis spectrophotometer, XPS, FESEM, STEM, ICP, XRF, etc.) for carrying out the aforementioned tasks.
8 - Fondazione Istituto Italiano di Tecnologia (IIT): Fondazione Istituto Italiano di Tecnologia (Italian Institute of Technology, IIT) is a scientific research centre based in Genoa (Italy) and established by Ministry of Education, University and Research and Ministry of Economy and Finance. Participation to the project will be through the Center for Space Human Robotics (CSHR) based in Turin. IIT, through its department CSHR, will be assisting SUPSI in the development of advanced materials for radiant porous burners providing advanced characterization of the developed materials. It will also take over the 3D printing development for the template and precursor structures of the ceramic porous radiant combustion zones. It will also be involved in the evaluation of the catalytic coated quartz properties at nanoscale, using a TEM and a Tribo-nanoindenter. The CSHR has a lab completely dedicated to the additive manufacturing/3D printing technology using Direct Metal Laser Sintering and Direct Light Processing technologies, coupled with sand blasting machine to enhance surface quality and properties.
9 - Colorobbia Consulting SRL (CC): Colorobbia Consulting S.r.l. is the services company of Gruppo Colorobbia that is one of the biggest producers of chemicals for ceramics in the world. Colorobbia will develop in collaboration with ERIC IR-transparent glass or glass-ceramic windows that will separate the burner section from the strip according to the ECCO specifications. Colorobbia will also manufacture the final IR-transparent windows that will be installed in the curing oven of the pilot coil coating line. According to the needs of their tasks, Colorobbia will use their production facilities and extensive research lab equipment.
10 - National Technical University of Athens (NTUA): The group of Prof. Founti at NTUA has a long tracklist of R&D activities on combustion modeling and related chemical kinetics as well as vast experience regarding the development and implementation of integrated assessment methodologies of innovative energy conversion systems, utilizing Multicriteria and Life Cycle Analysis methods under uncertainty. In the framework of ECCO, NTUA will contribute in the development of radiant porous burners by analysing combustion products composition and by developing a comprehensive chemical kinetic mechanism for the combustion of solvent vapour. NTUA will lead and will be responsible for the development of a holistic approach to measure, quantify, monitor and minimize the overall impact of the porous and radiant burners as well as their introduction in the curing stage of the coil coating process. (KPI-LCA-LCC approach).
11 - Instituto Superior Técnico (IST): The IST research group under the guidance of Prof. Pereira, has expertise on numerical modelling of fluid flow and heat and mass transfer. Large experience exists in the group in flow simulation with complex geometries, heat transfer and combustion in porous media, two-phase flows and turbulence and in the full simulation of entire furnaces, kilns (glass, ceramics, cements etc.) and boilers. IST will participate in tasks related with the detailed curing furnace section of the ECCO project by performing 3D numerical simulation of the flow, heat radiation and mass transfer occurring in the furnace sections. IST will also contribute by providing reduced models to provide virtual sensors for supporting the design of the curing oven control. The computational facilities at IST (four super-computers with 32 cores each and 512 Gb of RAM) will be used for the ECCO project.
12 - Thyssenkrupp Steel Europe AG (TKSE): ThyssenKrupp is a diversified industrial enterprise with innovations and technical progress as key factors for sustainable growth. ThyssenKrupp divides its activities into six business areas: Components Technology, Elevator Technology, Industrial Solutions, Materials Services, Steel Americas und Steel Europe. ThyssenKrupp Steel Europe, based in Duisburg, is amongst the global leaders in providing high-quality flat steel products. With around 27,000 employees and highly efficient manufacturing facilities the company produces ca. 12Mtons of crude steel annually, thus is the biggest manufacturer of flat steel products in Germany. TKSE will provide know-how regarding process and product specifications, will perform quality assessment of the final product and will contribute to the development of a complete business plan for the deployment of the ECCO developments. TKSE will also provide the required steel coils for the demo operation of the ECCO pilot coil coating line.
The technological solutions considered in the ECCO process have a strong potential for retrofitting existing coil coating production lines by increasing their compactness, modularity and flexibility.
Additionally, a provisional list of exploitation opportunities, the partners involved and the respective impact area is provided below:
Porous radiant burners with enhanced radiation efficiency at high radiation fluxes
GOGAS, KIT, SUPSI, ENGICER, IIT
Industrial thermo-processing facilities
Si-SiC ceramic structures based on 3D printing of precursor template for ceramisation
SUPSI, ENGICER, IIT
Tailored porous support structures for high temperature processes in the chemical industry and for thermo-processing equipment
IR-transparent ceramic tiles with self-cleaning surfaces suitable for high radiation flux transmissivity
Interesting for all IR indirect heated industrial thermal processes.
Innovative catalysts for decomposition of carbonaceous species at low temperatures and low oxygen/water partial pressures
Interesting for several industrial fields ranging from automotive exhaust gas cleaning, up to incineration of polluted air
Tailored paint composition for high radiation fluxes
Interesting for all coating processes with IR curing.
Combustion kinetics model for paint solvents
Combustion research, CFD prediction tools
Flow control for separation of the atmospheres at the strip inlet and outlet of the curing oven
IST, KIT GLOBUS, GOGAS
KPI based process control of coil coating line
GLOBUS, NTUA, GOGAS
Ideation of new research projects
KIT, IIT, SUPSI, ERIC, IST, NTUA,
This challenging and stimulating research field, where interdisciplinary research approaches are mandatory, offers an ideal background for the generation of new ideas for new products and processes to be explored in future research projects.
In ECCO, the specifications needed for a pilot coil coating line covering all equipment for batchwise processing of steel strips are defined. Three target products are identified and the corresponding coating formulations are specified in detail. A novel curing oven system operating under an oven atmosphere above the upper explosion limit incorporating radiant porous burners is specified. An IR-transmissive material is identified that separates the ECCO curing oven in a radiant burner section and curing oven section. Catalytic coatings avoiding the deposition of carbonaceous substances on the IR-transmissive material at high temperatures are developed. A strategy for the insulation of the curing oven section from ambient air based on pre- and postinertisation chambers hast been developed. For the porous burners, SiC based composite materials have been developed and tested under operating conditions exceeding the maximum operating temperature of current products. Novel additive manufacturing methods are investigated to directly print SiC based material with defined structures in a selective laser sintering process. Numerical simulations are applied to identify key mechanisms that have to be considered in the technical oven design. A detailed chemical kinetic mechanism based on surrogate fuels for the simulation of solvent combustion is developed and validated. An experimental facility for the characterization of solvent combustion in structured porous media is developed. Thermophysical and combustion properties of solvent formulations are investigated. A process model for the ECCO oven is established and operating conditions are derived. Computational tools for simulation of combustion coupled with radiative heat transfer in porous media are identified. A customized set of Key Performance Indicators is identified and the information carried in the KPIs is enhanced by incorporating a life cycle approach. Few business models for each solution implemented in ECCO can be developed using a Business Model Canvas. A dissemination strategy for the project runtime and after the project is developed.
Questions about the ECCO project can be sent to the Project Coordinator, so as to the Project Management team, as listed below:
Prof. Dr.-Ing. Dimosthenis Trimis
Karlsruher Institute of Technology
Division of Combustion Technology
Dipl.-Ing. Christof Weis
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