Numerical investigation of an innovative furnace concept for industrial coil coating lines

In this work, the engineering performance of an innovative furnace concept developed for continuous drying and curing of paint-coated metal sheets (coil coating process) is investigated through advanced modeling and numerical simulation techniques. Unlike the traditional and wide-spread coil coating furnaces – which operate according to the so-called convective air-drying technology –, the present furnace concept relies on infrared radiative heating to drive solvent evaporation and curing reactions. Radiative heat is provided by the operation of radiant porous burners which are fed with evaporated solvents. The current furnace concept consists of two main chambers (the radiant burner section and the curing oven section) with different gas compositions (atmospheres) that are separated by a semi-transparent window. The window allows energy transfer and prevents gas mixing between the two sections. To utilize the solvent-loaded atmosphere available in the curing oven section as fuel – and to prevent the development of explosive conditions therein –, a novel inertization concept shielding the curing oven section from the external environment is considered. The current furnace concept aims at improving process intensification and promoting energy efficiency. For the current furnace concept, numerical simulation results support a suitable and competitive performance for drying the applied coatings in comparison with the traditional approach. Simultaneously, a safe operation is predicted, without (i) solvent leakage from the furnace and (ii) oxygen entrainment from the surrounding ambient into the furnace. These conditions are satisfied demonstrating a safe operation and a complete evaporation of solvents from applied liquid film coatings

Numerical investigation of an innovative furnace concept for industrial coil coating lines

This research was funded by the European Community's Framework Programme for Research and Innovation Horizon 2020 under grant agreement no. 768692 (ECCO). Publisher Copyright: © 2023 The Author(s)In this work, the engineering performance of an innovative furnace concept developed for continuous drying and curing of paint-coated metal sheets (coil coating process) is investigated through advanced modeling and numerical simulation techniques. Unlike the traditional and wide-spread coil coating furnaces – which operate according to the so-called convective air-drying technology –, the present furnace concept relies on infrared radiative heating to drive solvent evaporation and curing reactions. Radiative heat is provided by the operation of radiant porous burners which are fed with evaporated solvents. The current furnace concept consists of two main chambers (the radiant burner section and the curing oven section) with different gas compositions (atmospheres) that are separated by a semi-transparent window. The window allows energy transfer and prevents gas mixing between the two sections. To utilize the solvent-loaded atmosphere available in the curing oven section as fuel – and to prevent the development of explosive conditions therein –, a novel inertization concept shielding the curing oven section from the external environment is considered. The current furnace concept aims at improving process intensification and promoting energy efficiency. For the current furnace concept, numerical simulation results support a suitable and competitive performance for drying the applied coatings in comparison with the traditional approach. Simultaneously, a safe operation is predicted, without (i) solvent leakage from the furnace and (ii) oxygen entrainment from the surrounding ambient into the furnace. These conditions are satisfied demonstrating a safe operation and a complete evaporation of solvents from applied liquid film coatings.publishersversionpublishe

Detailed Numerical Simulation for Optimization of Radiation Efficiency of Porous Burners

In porous burners, premixed combustion of gaseous fuels inside the cavities of an open-pore ceramic matrix heats the solid material to temperatures of 1400 °C, which leads to the emission of electromagnetic radiation with its intensity maximum at infrared light. The net thermal radiation emission can be used for efficient, fast and uniform heat transfer in various technical applications. Improving radiation efficiency correlates to increasing thermal radiation flux at constant thermal power, implicating a potential for reduction of fuel consumption and associated emissions for a given application. Additive manufacturing techniques offer new opportunities in the design of ceramic structures. However, the design of an optimized structure requires detailed knowledge of processes and conditions inside the porous matrix during operation, the experimental determination of which is complex and challenging. Inside the porous burner, chemical combustion reactions coincide with complex interaction between thermo-physical transport processes that occur within solid and gaseous phase, and across phase boundary. Flow, heat release and resulting heat flows influence each other. The numerical model used in this work considers gaseous and solid phases, includes flow, enthalpy transport, conjugate heat transfer, radiative heat transfer between solid surfaces as well as combustion kinetics according to a skeletal chemical reaction mechanism. These phenomena are resolved on the pore scale in three-dimensional space (Direct Pore Level Simulation, DPLS). The calculations are performed based on the finite volume method using standard applications implemented in the OpenFOAM library. The reactive flow and enthalpy field are calculated for a lateral periodical representative element of flat twolayer porous burner in full axial extension of flame trap and porous structure. The present study presents simulations of three different structures, each at four settings of specific thermal power. Results indicate that specific surface area of the porous structure is a major influencing parameter for increasing radiation efficiency, whereas no correlation of the orientation of an anisotropic structure on radiation efficiency was observed