Influence of Mechanical Agitation on Heat Transfer and Thermo Chemical Processes within Particle Assemblies on Grates and Small Incineration Systems

Project Number 328

The aim of this project is to investigate the influence of mechanical agitation on heat transfer and thermo chemical processes within particle assemblies through experiments and numerical simulation.

Granular media plays an important role in numerous industrial reactors, often designed or operated by small and medium enterprises. In the current project one main interest is to understand the processes occurring during the simultaneous thermal or thermo chemical treatment and mechanical mixing of the granular media. A validated engineering tool will be provided to predict the behaviour of the granular material based on computer simulations.

The Discrete Element Method (DEM) code developed at the department of Energy Plant Technology (LEAT) at the Bochum University models the movement of discrete particles and their interaction with surrounding particles or reactor walls. Additionally a simulation may include heat and mass transfer as well as chemical reactions within the granular material. A coupling of the DEM code with a commercial CFD code for the surrounding combustion air enables a detailed analysis of heat transfer and thermo chemical processes within particle assemblies on grates and small incineration systems. The modelling is going to be validated in the current project on the basis of specific test cases.

The model will describe the interaction of fuel transport, heterogeneous chemical reactions within the bed and primary combustion air in detail. This will allow developing control strategies based on geometrical and operational parameters of the grate system. At the end a modern and economic tool will be available for plant engineers and operators which assists grate design and grate operation.

The project is funded by the German Federal Ministry of Economics via the AiF (funding no. 16147N). It is carried out from July 2009 to December 2011 at the Bochum University (LEAT). The European Working Group Biomass and the Working Panel Thermal Waste Utilisation support and supervise the investigations.