Process modeling

Process modeling

process modeling, Recycling, Elektroschrott, e-waste, electronic waste, WEEE, Gold, Consulting, Project development, Projektentwicklung, Metallurgy, Metallurgie, Nachhaltigkeit, Sustainability, Klimaschutz, Climate protection, Green Deal,
Within the engineering phase of a metallurgical recycling plant, process modeling has been established as a powerful tool for supporting design work. Beside defining proper capacities for vessels and supply systems, a process model depicts the designated operation with enough accuracy to estimate economic figures. Furthermore, internal recycling streams can be considered, bottlenecks visualized, and possible operational challenges can be faced in an early stage.
A process concept is a visualisation of a designated metallurgical concept with basic unit data, as well as the major mass flows between the individual units. The process concept illustrates the efforts of establishing an additional production line. An off-gas treatment is a typical extension – which is especially recommended if a recycling of complex and/or hazardous elements containing raw material is processed.

Modelling with Excel

Process models prepared by using Microsoft Excel are a static estimation of a metallurgical process. Metal and slag compositions are usually estimated with sufficient accuracy, which allows an estimation of product qualities, as well as eventually required slag forming agents. Thermodynamic distributions are usually set as fixed values without any dependence of parameter variations. Iterations – required in case of multi-staged processes with internal recycling streams – are carried out manually. 

Thermodynamic modelling

In case of complex smelting and refining processes, software packages for thermodynamic calculations provide much more possibilities of estimating process parameters and products. These models include both mass and energy balance, as well as the possibility of an automated iteration procedure to optimize process and find parameters – also in case of internal recycling streams. Iterations can be programmed within a single process step (e.g. silica addition for a desired slag composition) but also for the overall process model (e.g. burner capacity for ensuring a desired bath temperature). Establishing such models usually requires more preparation on the one side. On the other side the program includes a variety of internal control mechanisms to ensure a consistent model.
Based on the process concept, as well as on the process model, a preliminary media consumption list can be prepared to define burner and lance capacities for example. Furthermore, the product quantity and quality are estimated. A basic off-gas composition and presumable dust, halogen and/or sulphur load are provided, if required. Based on this data, the gas cleaning plant can be designed.