MODELING AND OPTIMIZATION FOR DESIGN UNDER PRODUCTION PLANNING CRITERIA IN MULTIPRODUCT DEHYDRATION PLANTS

The design problem of a multiproduct dehydration plant involving conti nuous conveyor-belt dryers utilised for the dehydration of agricultura l products over a finite time horizon, is presented. The peculiarities of the problem under demand-varying market patterns and time-variable market prices of raw materials are underlined. Limitations imposed by storage capacity, customer orders, and constraints dictated by the pr ocess itself, are also taken into consideration. The overall problem i s cast into a MINLP formulation involving the total annual cost of die plant as its objective function. This was infered by deducing the mat hematical model of conveyor-belt dryers. Repeated evaluation of the to tal annual cost for various structures and operating points, allowed t he determination of overall performance characteristic operational and structural curves, approximated by suitable mathematical expressions. A test case is presented in order to demonstrate the effectiveness of the proposed approach.