Numerical Approach for the Implementation of the Interaction of Pyrolysis Gases and Combustion Products in an Aluminium-Melting Furnace

Abstract

Aluminium is a key material in modern society and serves the needs because of the unique properties of the metal and its alloys. Scientific evidence and rational economic theories have repeatedly demonstrated that recycling is the most critical and efficient pathway to sustainable human development. Aluminium products like Used Beverage Cans or Containers (UBCs) has been alloyed with other elements to fulfil consumer requirements and contain organic material due to paint and lacquer coatings on the body. The melting and pre-treatment of scrap has an emphasized role in the recycling chain of contaminated aluminium products. The relationship between the amount of contamination, pre-treatment and melting procedure and dross formation attains crucial attention in order to enhance the energy efficiency in existing furnaces. Therefore, understanding the melting and pre-treatment processes includes statistical surveys and systemic modelling. In the present work, numerical simulations were carried out using the commercial software FLUENT for generating a helpful tool in evaluating operational conditions. The main perspective is to analyze the relevant operational conditions inside an aluminium-melting furnace employing oxygen-fuel burner, which is capable to run in the flameless combustion mode. To cope with the challenge of simulating flameless combustion (highly diluted chemical conversion) proved detailed chemistry mechanisms are involved. Further crucial aspect is to evaluate additional in house written codes for the evaporation and gas release due to contaminated input material. Within the scope of the project P5 of the AMAP (Advanced Metals And Processes) research cluster in Aachen a virtual remelting furnace is set up as a CFD (Computational Fluid Dynamics) simulation for evaluating the terms of combustion, pyrolysis/ thermolysis, interaction of combustion products and pyrolysis gases and other crucial phenomena.