| "Energy conservation, protection of resources" to achieve sustainable development is China’s great strategy and means in the new era. China’s economy maintained high growth rate at8%since opening up and reformation. The rapid increase in energy demand has become the bottleneck of economic growth; energy conservation has become a long-term national strategy for economic development.The steel industry is energy-hungry in China. In the past few years, the steel industry has experienced rapidly, unconventional growth, resulting in relative surplus production capacity in the future on the one hand. On the other hand, a considerable number of steel corporations, with small-scale capacity, inefficient equipment utility, technology behind times, create a lot of waste. The steel roller manufacturing industry is the upstream industry in the steel production. Roller production process consists of the shaping, smelting, casting, thermal treatment, machining and many other procedures. The thermal treatment process has prominent importance in roller production process due to the long cycle and the high cost. Therefore, it is of great significance to improve the utilization rate of the furnace and reduce the energy consumption under the existing condition of resources.In this paper, based on the actual production of a domestic roller manufacturing corporation, through the company’s field research and application of production management and systems engineering principles, roller group batches, batch assignment and scheduling problems during thermal process were studied with the goal of energy conservation. The study is a sub-project of the National "973" and it is also an important part of the National Science Fund for Creative Research Groups. The main research work includes the following aspects:(1) Single-stage deterministic roller batching assignment and scheduling problem during thermal treatment process is studied with the goal of energy conservation, which comes down to a parallel machine scheduling problems with assignment. Mathematical models are established for the problems with furnaces different in the size and power; Three heuristic algorithms had been presented to solve the problem with the goal of energy saving.They are respectively heuristic algorithm based on First Coming, First Processing and Low-Power Furnace First (FCFP-LPFF), heuristic algorithm based on Longest Processing Time and Low-Power Furnace First (LPT-LPFF) and heuristic algorithm based on Largest Difference Value of Batch Processing Time and Low Unit Power Furnace First (LDVBPT-LUPFF); Simulation experiments are conducted under different scales for furnace with different available time, and comparison and analysis of experimental results verify the effectiveness and adaptability of algorithms.(2) Considering energy saving during thermal treatment process of roller, grouping, batch assignment and single-stage scheduling problems is studied, the problem is reduced to parallel machine scheduling problems with grouping and batch assignment. The problem considering single roller is an extension of the previous question, which is more consistent with actual production. Mathematical models are established for the problems with furnace different in the size and power. Two heuristic algorithms with grouping and assignment have been presented to solve the model with the goal of energy saving; They are respectively heuristic algorithm based on Largest Difference Value of Roller Sizes and Batch Processing Time and Low Unit Power Furnace First (LDVRS-BPTLUPFF) and heuristic algorithm based on Longest Roller Sizes and Processing Time and Low-Power Furnace First (LRS-PTLPFF). Calculate experiments are conducted under different scales for furnaces with different available time, and comparison and analysis of experimental results verify the effectiveness and adaptability of algorithms, which provides a reasonable suggestion for business decision makers. |
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