Avaliação das características físico-químicas do pó na definição de parâmetros operacionais para otimização da secagem por spray dryer

Abstract

This study addresses the problem of dust accumulation in spray dryers, a phenomenon that compromises process efficiency, increases operating costs, and reduces equipment availability. The rationale for the study lies in the high recurrence of unscheduled downtime associated with dust adhesion to the internal surfaces of the dryer, especially in the chamber and cyclones. The objective was to identify the factors that contribute to this behavior in a critical product, selected from the analysis of historical operating records. The methodology involved three main steps: categorization of historical data to confirm the highest incidence of accumulation, laboratory tests to estimate the glass transition range (Tg) by observing the onset of material stickiness, and evaluation of drying conditions using a psychrometric chart. The results showed that the product studied does indeed accumulate more frequently than the others, that the powder begins to agglomerate at a temperature range close to the process operating conditions, and that the current operating conditions are above the safe regions defined for less restrictive products, favoring the formation of deposits. The integrated analysis indicates that the tendency to accumulate results from the interaction between the physical-chemical characteristics of the product and operational parameters. As a recommendation, adjustments to the outlet temperatures of the chamber and fluidized bed are suggested, aiming to reduce stickiness, minimize cleaning downtime, and increase the overall efficiency of the process. The study contributes to the understanding of the mechanisms involved in powder accumulation in spray dryers and provides insights for optimizing drying conditions, representing an important step toward improving the process and industrial productivity.