Henning Bruns, Antje Rückert, Herbert Pfeifer
Within the scope of the project P5 of the Advanced Metals And Processes (AMAP) research cluster
in Aachen a virtual remelting furnace by means of Computational Fluid Dynamics (CFD) modelling
is set up to investigate the resource and energy efficiency of the aluminium recycling process in
such kind of furnaces. One part of this numerical furnace model is the implementation of pyrolysis
gas release from charged scrap based on experimental investigations. Pyrolysis specifies thermal
degradation of organic material without any oxygen present. Considered aluminium scrap types are
used beverage cans, drillings or sheet scrap, covered with either lacquer or cooling lubricant.
When charging this scrap into a melting furnace, first an evaporation of water / food residues takes
place and afterwards the organic contaminations degrade, leading to an emission of primarily hydrocarbons.
The latter is implemented into CFD simulations involving the following steps: the extensively analyzed
emissions from lab-scale experiments (utilizing mainly Fourier Transform Infrared (FT-IR)
spectroscopy) are post-processed with MATLAB, reproduced with kinetic models, simplified as
much as required and implemented into an exemplary virtual CFD furnace by using ANSYS Fluent
user-defined functions (UDFs). The presentation will give an overview of the abovenamed steps.
The paper will provide both, a brief look at the experimental setup as well as a detailed discussion
of the numerical implementation.
The purpose of the work presented is providing information about the numerical approach including
obstacles regarding the implementation of pyrolysis gas release into a numerical furnace model. The
gained knowledge, especially about the time / temperature-dependent change of the emissions’ calorific
value and thus the energetic contribution to the furnace, allows for new strategies in the field
of refined burner control.