Optimal Integration Of Tactical And Operational Planning Levels For Petrochemical Supply Chain Under Uncertainties

Petrochemical industry plays a basic role of national economic,but is characteriesed by high energy consumption,high resource occupation and complicated process system.With the increasing awareness of the limitation on petrol resource and the environmental impact,traditionally rough management manner is no longer suitable and more and more challenged in the development of morden petrochemical industry.Supply chain management,emphasizing the optimization of whole system,can be used to improve the operations of petrochemical industry in terms of the resources and environmental efficiency,and will increase significantly the economic and social benefits of the entreprises.There are a variety of uncertainties in the supply chain,such as products demand & price,supply situation of raw materials etc.Decision making considering supply chain optimization under uncertainties is extremely important for the industry to increase the anti-risk ability.And thus it is necessary to consider uncertainty in both the theoretical and practical research.Supply chain management can be divided into three decision-making levels in terms of time dimension,including strategic level(long-term),tactical level(medium-term)and operational level(short-term),strategic level focus on design of supply chain,and other two levels focus on the planning and scheduling of supply chain.More feasible and accurate decision can be made by integrating the two levels.In the present work,the researches on petrochemical industry supply chain and optimization method under uncertainties were reviewerd,and the problem of tactical planning and operational scheduling under uncertainties in petrochemical industry supply chain was studied.The details are listed as follows:(1)Scenario analysis method and Monto Carlo method were respectively used to generate uncertainty scenarios.The uncertainties of products demand and price in the tactical level,and the raw materials supply situation and equipment maintenance time of refinery in the operational level were considered.(2)A finite scenario based two-stage stochastic mixed integer linear programming(MILP)model was proposed to optimize the multi-period and multi-echelon petrochemical industry supply chain in tactical decision-making level under uncertainties.The model considered environmental objective by taking into account the CO2 emission reduction in the economic objective via carbon tax.The operating units in the process of the refinery entities in the chain were regarded as “black box”,to simplify the complicated system.The result was analyzed in terms of risk management,and the model with risk management constraints was formulated.(3)A finite scenario based two-stage stochastic MILP model was proposed to optimize the scheduling of three refineries with different internal process in operational decision-making level under uncertainties.In the optimization formulation,the units of refineries were divided into three types: reaction unit,separation unit as well as storage unit,to simplify the complicated process system.(4)Tactical planning optimization model and operational refinery scheduling optimization model were integrated into an iteration model to optimize the petrochemical industry supply chain.As a result,a more feasible tactical planning and operational scheduling can be obtained.