OPTIMAL CAMPAIGN PLANNING SCHEDULING OF MULTIPURPOSE BATCH SEMICONTINUOUS PLANTS .1. MATHEMATICAL FORMULATION

A general mathematical formulation for multiple campaign planning/sche duling of multipurpose batch/semicontinuous plants is presented. In co ntrast to sequential approaches, a single-level formulation is develop ed 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 const ituent products), and for every campaign the unit-task allocations, th e task timings, and the now of material through the plant. A cyclic op erating schedule is repeated at a fixed frequency within each campaign , thus simplifying significantly the management and control of the pla nt operation. The problem is formulated as a single-level mixed intege r Linear programming model. Issues pertaining to its solution are cons idered in the companion paper.