An Input Configuration Algorithm for Iron and Steel Material Yard

摘要

There are two main functions in management of the raw material yard of iron and steel. One is to reserve the raw material in order to keep on continuous production in case of variation in utilization. The other is to reassure the stability of material input and guarantee the accurate and stable quality of output production. Material field disposition is to optimize storage space allocation according to input schedule, basic information on raw material and other principals. Its essence is the optimization of space selection. The key points of material yard management is to enhance the quality of output production and reduce the management cost. Material field disposition is a key content in material yard management. Reasonable storage space allocation plays an important role in raw material management and could enhance the u-tilization of material yard and the accuracy of using material. After being rebuilt in 2005, the raw material yard in Bao Steel and Iron Corporation owns more than 700 pieces of conveyer belt, 39 stackers and reclaimers, and the material processing ability is 120 million ton per year. With the increases of working process and customer demand, it' s necessary to enhance the utilization of material yard space and facilities in order to reduce the management cost. On the other hand, the quality of output iron and steel is sensitive to the variation of the content of raw material. Thus, raw material with similar content should be placed as near as possible, and those with different content should be placed far away from each to avoid confusion in utilization. For material yard management, the purpose to increase the output quality and to enhance the utilization of space is contradictory to each other. How to balance these two objectives to optimize material field disposition is a multi-objective question. Furthermore, the exact time of material import is uncertain. The material resources are various and complicated, including Brazil, Australia and so on. The iron ore mainly depends on importing from overseas and more than half of them are from Brazil that is 12 thousand sea miles from China. The long shipping distance leads to unpredictable situation. Thus, during the process of making configuration planning, the current and future situation should be put together to consider. Due to the variation and uncertainty of future situation, the disposing plans need to be adjusted from time to time. Therefore, an effective input algorithm is needed to increase the efficiency and precision of making plans. To estimate different configuration plans needs both qualitative and quantitative analysis. Material yard configuration is influenced by multifarious factors, and abided by multiple principles. Thus, it is a multi-objective and multi-principle problem. AHP theory is a concise and powerful tool in evaluating different objects under multi-objective and multi-principle situation and has obvious priority in solving non-structural decision-making problem. To begin with, we need to work out the formula to quantitate the factors that influence the effectiveness of material configuration and work out the influencing right of these factors. Secondly, the right each of these factors takes account in all is calculated by pair-wise comparison in AHP. After this, the score on to what extent each empty place meets the requirement of each material could be calculated. After all, 0-1 integer programming model is used to determine the best resolution for space disposition. More over, practical example is given to prove the effectiveness of this algorithm , and the shortcomings and possible improvement of the algorithm and mathematical model are also pointed out.