Pareto design of fluidized bed dryers

Most of the research efforts in the field of fluidized dryer design, focus on the evaluation of the appropriate structural and operational process var iables so that total annual plant cost involved is optimized. However, the increasing need for dehydrated products of the highest quality, imposes the development of new criteria that, together with cost components, determine the design rules for any drying process. Quality of dehydrated products is a complex resultant of properties characterizing the final products, where the most important one is color. Color is represented by three parameters: redness, yellowness and lightness. These three parameters of a dried produ ct should deviate from that of its original material as little as possible. In this case, fluidized bed dryer design is a complex multi-objective opti mization problem, involving the color deviation and the unit cost of final product as an objective vector and as constraints described in process mode ls. The mathematical model of the dryer was developed and the fundamental c olor deterioration laws and critical financial parameters were determined f or the fluidized bed drying process. In this paper, non-preference multi-cr iteria optimization methods were used and the Pareto-optimal set of efficie nt solutions was evaluated. An example for drying of sliced potato was stud ied in detail to demonstrate the design procedure, the process performance as well as the effectiveness of the proposed approach. (C) 2000 Elsevier Sc ience S.A. All rights reserved.