CIESC Journal ›› 2016, Vol. 67 ›› Issue (9): 3804-3811.DOI: 10.11949/j.issn.0438-1157.20151584

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Multi-objective optimal strategy for steam power system in steel industry based on electricity equivalent calculation

CHEN Jun, ZHOU Weiguo, WANG Hai, LI Su   

  1. School of Mechanical Engineering, Tongji University, Shanghai 200092, China
  • Received:2015-10-20 Revised:2016-06-20 Online:2016-09-05 Published:2016-09-05

基于等效电法的钢铁企业蒸汽系统多目标运行优化策略

陈骏, 周伟国, 王海, 李苏   

  1. 同济大学机械与能源工程学院, 上海 200092
  • 通讯作者: 周伟国

Abstract:

The steam power system in steel industries is featured by a variety of energy and various energy producers. In this paper, a method to convert energy into electricity equivalent is introduced to analyze the efficiency of energy conversion in the system, and mathematical programming and optimization are employed to improve energy management based on the background of steam power system in a large iron and steel company. With the establishment of mixed integer nonlinear programming model which is multi-objective, the global optimal solution will be achieved by solve the multi-objective-constrained model by LINGO step by step on condition that the objectives, the minimum cost of energy hourly and the maximum exergy efficiency, and the constraints including the capacity of power plants, energy demand and operating cost are set. Pareto front is to be achieved by solving the objective function-the maximum exergy efficiency-with cost constraint by the minimum cost of energy hourly multiplying an over-relaxation which is little bigger than 1. Rationality, feasibility and efficiency of ultimate optimization solution by stepwise multi-objective optimization is to be demonstrated in comparison with solutions by single-objective optimization and multi-objective genetic algorithm. The schedule of effective operation at low cost of steam power system is to be well-founded in theory in accordance with the optimal solution.

Key words: steam system, electricity equivalent calculation, multi-objective optimization, mathematical modeling, optimization, exergy

摘要:

针对钢铁企业蒸汽系统汽源设备多、能源品种多的特点,以某大型钢铁企业实际运行的蒸汽系统为背景,运用等效电方法对蒸汽系统的能量转换作出科学分析,采用数学规划方法,建立多目标的混合整数非线性规划模型(MINLP)。采用分步优化方法,先以蒸汽系统小时能源总成本最低为目标,将得到的结果乘以松弛系数建立成本约束并以(火用)效率最高为目标,利用LINGO软件求得多目标-约束优化模型的全局最优解,再通过改变松弛系数得到一组Pareto前沿。最后与单目标优化和多目标遗传算法结果相比较,证明分步优化方法所得的结果是可行的综合最优结果,能够实现低成本和高(火用)效率的双目标,并为生产调度提供依据。

关键词: 蒸汽系统, 等效电方法, 多目标优化, 数学模型, 优化, (火用)

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