Product quality multi-objective dryer design

Design of conveyor-belt dryers constitutes a mathematical programming probl em involving the evaluation of appropriate structural and operational proce ss variables so that total annual plant cost involved is optimized. The inc reasing need for dehydrated products of the highest quality, imposes the de velopment of new criteria that, together with cost, determine the design ru les for drying processes. Quality of dehydrated products is a complex resul tant of properties characterizing the final products, where the most import ant one is color. Color is determined as a three-parameter resultant, whose values for products undergone drying should deviate from the corresponding ones of natural products, as little as possible. In this case, product qua lity dryer design is a complex multi-objective optimization problem, involv ing the color deviation vector as an;objective function and as constraints the ones deriving from the process mathematical model. The mathematical mod el of the dryer was developed and the fundamental color deterioration laws were determined for the drying process. Non-preference multicriteria optimi zation methods were used and the Pareto-optimal set of efficient solutions was evaluated. An example covering the drying of sliced potato was included to demonstrate the performance of the design procedure, as well as the eff ectiveness of the proposed approach.