Optimal campaign planning scheduling of multipurpose batch semicontinuous plants .1. Mathematical formulation

A general mathematical formulation for multiple campaign planning/scheduling of multipurpose batch/semicontinuous plants is presented. In contrast to sequential approaches, a single-level formulation is developed encompassing both overall planning considerations pertaining to the campaign structure and scheduling constraints describing the detailed operation of the plant during each campaign. The problem involves the simultaneous determination of the campaigns (i.e., duration and constituent products), and for every campaign the unit-task allocations, the task timings, and the now of material through the plant. A cyclic operating schedule is repeated at a fixed frequency within each campaign, thus simplifying significantly the management and control of the plant operation. The problem is formulated as a single-level mixed integer Linear programming model. Issues pertaining to its solution are considered in the companion paper.