Basic concepts of spray dryer design

Abstract

The major parameters in the design of spray dryers are discussed. A Lagrangian approach, combining experimental data with theoretical concepts, is proposed to develop design methods. Vortex flow patterns, obtained experimentally in a laboratory size chamber, are correlated and presented. Based on this design methodology, computational methods are given to calculate droplet trajectories and hence to predict the optimum chamber dimensions and operating conditions for maximum thermal efficiency and/or minimum operating cost. Application of these basic principles is illustrated by the design of an industrial size, spray drying chamber for a specific feed solution and production rate.

One-dimensional simulation of co-current, dairy spray drying systems – pros and cons

“…The 1-D simulation approach has previously been used to model spray drying operations due to its ability to predict a product's moisture, temperature and velocity profiles throughout drying [30,31,48,66,70,72,73,109,112]. Three main components to formulate the 1-D simulation tool for modeling spray drying processes are (1) drying kinetics data from laboratory-scale experiments and drying kinetics model, (2) a set of appropriate mathematical equations, and (3) a process calculation tool (e.g.…”

“…Drying processes are simulated using overall heat and mass balance equations to predict gas temperature, gas humidity and product moisture content at the inlet or outlet of dryers [10]. Drying chambers are mostly treated as well-mixed reactors [30,95,110]. Calculations for heat and mass balances over spay dryers and fluidized-bed dryers are usually done separately.…”

Atomized Suspension Drying and Processing

“…The spray drying operation has been the object of 'nany experimental studies in this laboratory, which finally culminated in a proposed theory of .pray dryer design by Gauvin and Katta (1976). In an effort to improve the efficiency of the operation and lower its cost, a techno-economic study was undertaken by Gauvin and Costin (1980) using the above nentioned design theory, to compare the use of a closed cycle with steam as the drying medium (as shown in Figure 2) with a conventional hot air system of the same evaporative capacity_ Substantial gains in capital and operating costs were predicted for the steam cycle by this study, hut an experimental verification of these predictions was shelved in favor of an even more promising approach, namely the use of a plasma of~ater as the heating medium.…”

A novel approach to spray drying using plasmas of water vapour

“…Using the above modifications and assumptions in the program, the same industrial application for the production of 1000 kg of product per hour as previously considered by Gauvin and Katta (1976) and Gauvin and Costin (1980) will again be used a s an illustration of the new proposal, to facilitate comparison between the three approaches shown in Figures 1, 2 and 5, respectively. Table 1 summarizes the specifications and requirements of the drying operation, while Table 2 describes the specifications of the atomizing nozzle.…”

“…This idea is certainly not new, but nobody to date, to the author's knowledge, has published a detailed consideration of this possibility. Briefly summarized, the study consisted of a comDarison of the conventional hot air system (Figure 1) with one using recycled superheated steam (Figure 2) based on a computer program developed by Gauvin and Katta (1976) for predicting the size of a spray drying chamber for specific applications (chamber geometry, rate of production, product specifications, types of atomizers, etc.) .…”