Supply chain management using an optimization driven simulation approach

In this work, we propose a hybrid simulation‐based optimization framework to solve the supply chain management problem. The hybrid approach combines a mathematical programming model with an agent‐based simulation model and uses them in an iterative framework. The optimization model is used to guide the decisions toward an optimal allocation of resources given the realistic supply chain representation given by the simulation. Thus, the proposed approach provides a more realistic solution compared to a stand‐alone optimization model, often a simplified representation of the actual system, by making use of the simulation model, which captures the detailed dynamic behavior of the system. A multiobjective problem has been formulated by taking into consideration the environmental impact of supply chain operations. The proposed framework has been applied to small‐scale case studies to study the effectiveness of the approach for such problems. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4612–4626, 2013     

改进生物地理学优化算法及其在汽油调合调度中的应用

汽油调合和调度优化问题中含有典型的非线性约束(NLP)问题。针对一般智能优化算法在解决此类优化问题中易陷于局部极值,提出了一种改进的生物地理学优化算法(HMBBO)。该算法设计了一种基于种群个体差异信息的启发式变异算子,弥补了Gauss变异、Cauchy变异算子缺乏启发式信息的不足,以解决原算法在局部搜索时易出现的早熟问题,提高算法的全局搜索能力,并且采用非线性物种迁移模型以适应不同的自然环境。采用4个测试函数进行仿真,结果表明:HMBBO算法与标准BBO算法、基于Gauss变异及基于Cauchy变异的BBO算法比较,其收敛速度和全局寻优能力有明显改善。汽油调合和调度优化实例表明,该算法能够快速有效地找到全局最优解。     

Efficient scheduling method of complex batch processes with general network structure via agent‐based modeling

A novel efficient agent‐based method for scheduling network batch processes in the process industry is proposed. The agent‐based model is based on the resource‐task network. To overcome the drawback of localized solutions found in conventional agent‐based methods, a new scheduling algorithm is proposed. The algorithm predicts the objective function value by simulating another cloned agent‐based model. Global information is obtained, and the solution quality is improved. The solution quality of this approach is validated by detailed comparisons with the mixed‐integer programming (MIP) methods. A solution close to the optimal one can be found by the agent‐based method with a much shorter computational time than the MIP methods. As a scheduling problem becomes increasingly complicated with increased scale, more specifications, and uncertainties, the advantages of the agent‐based method become more evident. The proposed method is applied to simulated industrial problems where the MIP methods require excessive computational resources. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2884–2906, 2013     

基于序的原油调合调度问题

原油在线调合调度对于平稳混炼原油性质、保障先进控制的实施和优化炼油计划具有重要的意义。原油调合调度问题由于既包括顺序变量又包括连续变量,不存在明确的问题结构,复杂度高,传统的优化方法效率低,不能满足在线实时的要求。本文针对问题的两层结构提出了基于序的求解方案,利用实际原油性质数据的仿真结果表明,基于序的求解算法可以大幅度提高计算效率。     

不确定条件下炼化企业计划与调度整合策略

A strategy for the integration of production planning and scheduling in refineries is proposed.This strategy relies on rolling horizon strategy and a two-level decomposition strategy.This strategy involves an upper level multiperiod mixed integer linear programming(MILP) model and a lower level simulation system,which is extended from our previous framework for short-term scheduling problems [Luo,C.P.,Rong,G.,\"Hierarchical approach for short-term scheduling in refineries\",Ind.Eng.Chem.Res.,46,3656-3668(2007)].The main purpose of this extended framework is to reduce the number of variables and the size of the optimization model and,to quickly find the optimal solution for the integrated planning/scheduling problem in refineries.Uncertainties are also considered in this article.An integrated robust optimization approach is introduced to cope with uncertain parameters with both continuous and discrete probability distribution.     

A projection‐based method for production planning of multiproduct facilities

An algorithm is presented for identifying the projection of a scheduling model's feasible region onto the space of production targets. The projected feasible region is expressed using one of two mixed‐integer programming formulations, which can be readily used to address integrated production planning and scheduling problems that were previously intractable. Production planning is solved in combination with a surrogate model representing the region of feasible production amounts to provide optimum production targets, while a detailed scheduling is solved in a rolling‐horizon manner to define feasible schedules for meeting these targets. The proposed framework provides solutions of higher quality and yields tighter bounds than previously proposed approaches. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Multi‐period planning,design, and strategic models for long‐term,quality‐sensitive shale gas development

In this work we address the long‐term, quality‐sensitive shale gas development problem. This problem involves planning, design, and strategic decisions such as where, when, and how many shale gas wells to drill, where to lay out gathering pipelines, as well as which delivery agreements to arrange. Our objective is to use computational models to identify the most profitable shale gas development strategies. For this purpose we propose a large‐scale, nonconvex, mixed‐integer nonlinear programming model. We rely on generalized disjunctive programming to systematically derive the building blocks of this model. Based on a tailor‐designed solution strategy we identify near‐global solutions to the resulting large‐scale problems. Finally, we apply the proposed modeling framework to two case studies based on real data to quantify the value of optimization models for shale gas development. Our results suggest that the proposed models can increase upstream operators’ profitability by several million U.S. dollars. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2296–2323, 2016     

粉状聚丙烯增韧增强研究

采用机械共混方法对粉状聚丙烯（PP）进行了增韧增强研究,探讨了增韧剂、增强剂和有少量自制的固相甲基丙烯酸（MAA）接枝粉状聚丙烯（PP-g-MAA)作增容剂存在下对粉状PP共混体系力学性能的影响,用热重分析法考察了改性粉状PP的热性能。结果表明,（乙烯／丙烯／二烯）共聚物（EPDM）／高密度聚乙烯（HDPE）为复合增韧剂,具有协同作用,可显著提高共混物的冲击强度：PP-g-MAA能明显改善PP／玻纤两相的界面结合力;PP／EPDM／HDPE玻璃纤维共混体系可以获得理想的增韧增强效果。     

基于微粒群优化算法的不确定性调和调度

Blending is an important unit operation in process industry. Blending scheduling is nonlinear optimization problem with constraints. It is difficult to obtain optimum solution by other general optimization methods. Particle swarm optimization （PSO） algorithm is developed for nonlinear optimization problems with both continuous and discrete variables. In order to obtain a global optimum solution quickly, PSO algorithm is applied to solve the problem of blending scheduling under uncertainty. The calculation results based on an example of gasoline blending agree satisfactory with the ideal values, which illustrates that the PSO algorithm is valid and effective in solving the blending scheduling problem.     

A cost‐effective model for the gasoline blend optimization problem

Gasoline blending is a critical process with a significant impact on the total revenues of oil refineries. It consists of mixing several feedstocks coming from various upstream processes and small amounts of additives to make different blends with some specified quality properties. The major goal is to minimize operating costs by optimizing blend recipes, while meeting product demands on time and quality specifications. This work introduces a novel continuous‐time mixed‐integer linear programming (MILP) formulation based on floating time slots to simultaneously optimize blend recipes and the scheduling of blending and distribution operations. The model can handle non‐identical blenders, multipurpose product tanks, sequence‐dependent changeover costs, limited amounts of gasoline components, and multi‐period scenarios. Because it features an integrality gap close to zero, the proposed MILP approach is able to find optimal solutions at much lower computational cost than previous contributions when applied to large gasoline blend problems. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3002–3019, 2016     

新型美白剂Arlatone DCA的研究进展

讨论了新型美白剂Arlatone DCA的配方技巧和美白效果。采用FfE理论可以促进美白效果最大化,而最新的临床测试数据也证实了DCA拥有明显的美白效果。     

尼龙6共混增韧改性的研究

利用双螺杆挤出机通过熔融共混制备了尼龙6/三元乙丙橡胶(EPDM)/接枝三元乙丙橡胶(EPDM g MAH)和尼龙6/接枝三元乙丙橡胶(EPDM g MAH)塑料合金,并研究测定了其吸水性、力学性能和流变行为。结果表明:接枝三元乙丙橡胶明显改善尼龙6与三元乙丙橡胶之间的相容性,合金的吸水率明显降低,在保持较高强度的同时冲击性能远远优于尼龙6,接近或超过韧性尼龙;熔体指数明显下降、成型加工性较尼龙6明显改善。     

不同瘦化剂在配煤炼焦中的研究进展

对冶金焦粉、石油焦粉和无烟煤等瘦化剂的来源及性质进行了总结。探讨了不同瘦化剂在配合煤成焦过程中的作用机理。得出冶金焦粉可改善焦炭抗碎强度和提高块焦率;石油焦粉可改善焦炭耐磨强度和反应后强度,降低灰分含量;无烟煤可代替部分瘦煤,降低焦炭反应性和硫含量。     

超韧PA6射钉弹弹夹的研制

采用自制的接枝聚乙烯(PE)增容剂和PE对尼龙6(PA6)进行改性,研制出超韧PA6射钉弹弹夹专用料,其悬臂梁缺口冲击强度高达82kJ／m^2。用该专用料生产的高能量射钉弹弹夹已组装出口至韩国、美国、日本及东南亚地区。     

Multienterprise supply chain: Simulation and optimization

The advancements in connectivity among the entities belonging to industrial supply chain have given rise to more complex, global supply chain networks. These networks are often constituted of entities that belong to multiple such networks. Interactions among the entities in such networks are also influenced by whether they belong to the same enterprise or different ones. This work takes into consideration the effect of such interactions. The entities belonging to different enterprises are assumed to interact through auctions. An agent based simulation model that incorporates such auctions is used to represent multienterprise supply chain networks. The dynamics of the supply chain affected by the auction mechanism are investigated. Also a derivative free optimization methodology is proposed to find the optimal warehouse capacities for the minimization of total cost. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3392–3403, 2016