J. Biedermann1, L.Cromme1, K. Weber1, S. Würll1, F. Rehn2 and L. Rhede2
1Technische Universität Cottbus, Lehrstuhl Numerische und Angewandte Mathematik
2Lausitzer Braunkohle AG
At the Schwarze Pumpe Briquette Works of the Lusatian Brown Coal Corporation (LAUBAG) new plants have been set up for the packaging of briquettes in the sizes offered, i.e. 25 kg-bundles, 10 kg-bags and 10 kg-foil packs. The running-in period of these new plants was accompanied, as anticipated, by outages in the early stages and by necessary modifications during current production, which either individually or as a whole resulted in reduced performance as far as the target of 85% bundle output was concerned. Because of the complex nature of the technical production and automation processes it was imperative to evolve stabilizing measures and also to seek new methods of plant operation and throughput that would effectively do away with interruptions and active experiments during current production and could nevertheless be used to check the necessary production sections and could be applied to the new plants. As a means of representing the production lines of pressing and bundling the method of modelling and simulation was preferred, and this was developed by the Chair of Numerical and Applied Mathematics at the Brandenburg Technical University of Cottbus, in close collaboration with the LAUBAG, and was realized on SUN workstations (operating system UNIX). Models were completed for the briquette press with integrated control, for the entire 25 kg-bundle packaging line and the production line for the 10 kg-foil packs. By modelling and simulation of the pressing section it could be ascertained that concerning the control effectiveness the preset parameter combinations for the briquette thickness controls of the presse lie in the optimum range. Alternative modern types of control produce no improvements as compared to the three-point briquette thickness control. The model developed for the reference value setting by the application of numeric optimization processes has revealed reserve capacity potentials in the case of the briquette presses. Simulation of the 25 kg-bundle packaging line, on the one hand, proved the capacity of the transport lines under full load, but, on the other hand, also draw attention to weak points. It was ascertained that the use of the briquette-layer weight control can definitely reduce the performance of the automatic bundling devices and for this reason should continue to remain switched off. It will be used again in future when the reference value setting has been changed. An optimum distribution of the streams of bundles in front of the two palettizers can prevent pile-ups. An analysis of the packaging and transport sequences led to suggestions for improvements to the 10 kg-foil pack production line. The purpose of the facts presented here on the modelling and simulation of partial processes of briquette production and packaging was to show how findings that are effective in actual practice and economic advantages can be achieved by close collaboration between a university and an industry and by co-ordinating basic scientific and technical work with the application of the results on the production process.