Delft University of Technology
Faculty Mechanical, Maritime and Materials Engineering Transport Technology
O.M. Kooymans Een lineair programmeringsmodel voor de inzet van reststoffen bij Hoogovens. Masters thesis, Report 93.3.LT.4125, Transport Engineering and Logistics.
At Hoogovens IJmuiden remainder materials are being released when steel is produced.Those materials that contain iron are recycled in the proces of iromnaking. At Hoogovens these materials are called 'industrial materials'. This circular course flows via a storage terrain where all the industrial materials are stored separately. From this storage the materials are transported by truck to another dump where they are mixed. The planning that is used for the transportation of the industrial materials is the subject of this project.
In the preliminary investigation of this study an overview of the flows of industrial materials is made. This investigation makes clear that the planning of industrial materials exerts an influence to different aspects. The proportion of the various industrial materials exerts its influence to the composition of the mixture. Chemical limits are set to the mixture; those limits should not be exceeded. With the planning it is possible to control the stocks of the industrial materials. Minimal stock is strived after. On the other hand, the continuity of the mixture needs a continuous planning. The continuity of the mixture is important because of the resets of the sinter producing proces.
To support the making of the planning, a lineair programming model is developed. With a horizon of half a year this model calculates a planning that strives after minimwn stock value. Chemical limits and the minimum stocks are the restrictions where the planning must stick to. Continuity criterions are modelled, so a modification in the planning is adviced only if the profit is higher than the reset costs of this modification. The main function of the model consists of four subfunctions: capital management, chemical management, stock management and continuity management.
An application of the LP-model of the industrial materials planning is written in the lineair progranuning system XA, with a shell of PreXA. For modification of the input and analysis of the output the spreadsheet program Excel is used. Worksheats are defined to present the information in grafics and tables. With a configuration of the LP-model of the planning of industrial materials some experiments are done to demonstrate the possibilities of the model. This configuration is a model of the actual system of industrial materials at Hoogovens and can be used to support the planning.
While not all criterions of the industrial materials are known quantitativily, the application does not use all possibilities of the model. When the criterions of the chemical composition of the mixture are quantified, these extra possibilities can be used effectivly. Also with a limited configuration, which is easier accessible for the user, the model can support the making of a planning for the industrial materials.
Reports on Transport Engineering and Logistics (in Dutch)
