BATCH PLANT-DESIGN AND OPERATIONS UNDER UNCERTAINTY

The paper addresses the problem of including aspects of uncertainty in process parameters and product demands at the design stage of multipr oduct/multipurpose batch plants. A conceptual two-stage stochastic pro gramming formulation is proposed with an objective function comprising investment costs, expected revenues from product sales, and a penalty term accounting for expected losses due to unfilled orders. It is sho wn that (i) the proposed formulation captures the various decision-mak ing policies toward demand satisfaction in a unified way, (ii) the emp loyed feasibility, criterion for the incorporation of the uncertainty enables the exact reformulation of the two-stage model as a single lar ge-scale optimization model, (iii) for the case of discrete equipment sizes and despite the use of general continuous probability distributi on functions to describe the uncertainty, linearity of the model is pr eserved, allowing detailed scheduling models to be included directly i n the optimization model, and (iv) for the case of continuous equipmen t sizes, a careful exploitation of the model structure allows for the development of an efficient global optimization procedure. The versati lity of the proposed unified framework is demonstrated with example pr oblems covering different batch plant design and scheduling formulatio ns previously suggested in the open literature.