Browsing by Author "Mages, Alexander"

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    Comparative life cycle sustainability assessment of mono- vs. bivalent operation of a crucible melting furnace
    (2022) Schutzbach, Maximilian; Kiemel, Steffen; Miehe, Robert; Köse, Ekrem; Mages, Alexander; Sauer, Alexander
    The benefits of energy flexibility measures have not yet been conclusively assessed from an ecological, economic, and social perspective. Until now, analysis has focused on the influence of changes in the energy system and the ecological and economic benefits of these. Therefore, the objective of this study was to perform a life cycle sustainability assessment of energy flexibility measures on the use case of a bivalent crucible melting furnace in comparison with a monovalent one for aluminum light metal die casting. The system boundary was based on a cradle-to-gate approach in Germany and includes the production of the necessary process technologies and energy infrastructure and the utilization phase of the crucible melting furnaces in non-ferrous metallurgy. The LCSA is performed for different economic and environmental scenarios over a 25-year lifetime to account for potential adjustments in the energy system and volatile energy prices. In summary, it can be said that over the entire service life, no complete ecological, economic, and social advantage of energy flexibility measures through a bivalent system can be demonstrated. Only a temporarily better life cycle sustainability performance of the bivalent furnace can be shown. All results must be considered with the caveat that the bivalent crucible melting furnace has not yet been investigated in actual operation and the calculations of the utilization phase are based on the monovalent crucible melting furnace. To further sharpen the results, more research is needed and the use of actual data for bivalent operation.
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    Comparison of the temperature, radiation, and heat flux distribution of a hydrogen and a methane flame in a crucible furnace using numerical simulation
    (2024) Mages, Alexander; Sauer, Alexander
    Sustainable technologies to replace current fossil solutions are essential to meet future CO2 emission reduction targets. Therefore, this paper compares key performance indicators of a hydrogen- and a methane-flame-fired crucible furnace with computational fluid dynamics simulations at identical firing powers, aiming to fully decarbonize the process. Validated numerical models from the literature were used to compare temperatures, radiation fields, radiation parameters and heat transfer characteristics. As a result, we observed higher combustion temperatures and a 19.0% higher fuel utilization rate in the hydrogen case, indicating more efficient operating modes, which could be related to the increased radiant heat flux and temperature ranges above 1750 K. Furthermore, higher scattering of the heat flux distribution on the crucible surface could be determined indicating more uneven melt bath temperatures. Further research could focus on quantifying the total fuel consumption required for the heating up of the furnace, for which a transient numerical model could be developed.
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    Numerical investigation and simulation of hydrogen blending into natural gas combustion
    (2024) Jung, Laura; Mages, Alexander; Sauer, Alexander
    This study reviews existing simulation models and describes a selected model for analysing combustion dynamics in hydrogen and natural gas mixtures, specifically within non-ferrous melting furnaces. The primary objectives are to compare the combustion characteristics of these two energy carriers and assess the impact of hydrogen integration on furnace operation and efficiency. Using computational fluid dynamics (CFD) simulations, incorporating actual furnace geometries and a detailed combustion and NOx emission prediction model, this research aims to accurately quantify the effects of hydrogen blending. Experimental tests on furnaces using only natural gas confirmed the validity of these simulations. By providing precise predictions for temperature distribution and NOx emissions, this approach reduces the need for extensive laboratory testing, facilitates broader exploration of design modifications, accelerates the design process, and ultimately lowers product development costs.
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    ItemOpen Access