GOALI: Improvements Spray Drying Manufacturing Through Control of Drop Size Distributions

Purdue University, West Lafayette IN

Investigators

Abstract

The goals of this Grant Opportunities for Academic Liaison with Industry (GOALI) project are: (1) to improve spray dryer manufacturing processes by developing fundamental models for the design of advanced spray units that produce well-controlled drop size distributions; and (2) to address a current issue of fundamental concern to the spray research community, determining whether the maximum entropy formalism (MEF) or the discrete probability function method (DPF) is most appropriate for predicting drop size distributions under typical industrial conditions. Spray drying is a critical materials processing technology used in areas as diverse as pharmaceutical processing, pigment manufacture, and production of fertilizers and foodstuffs. While the range of product specifications (i.e., particle sizes) differs in each case, the underlying goal is to produce products having a narrow distribution of sizes centered about a targeted mean. Currently, procedures for designing spray dryers are ad hoc and require considerable trial and error, especially when scaling up from pilot to full-scale production. To accomplish the goals of this project, the aim is to fabricate a unique micro-spray system having well-controlled and measurable initial and boundary conditions so that model inputs describing fluctuations in manufacturing process operating variables (liquid supply pressure and unsteadiness in the surrounding gas environment), manufacturing tolerances associated with the machinery itself (variations in atomizer channel width and height), and material property differences (arising from compositional changes) can be evaluated. This work will have broad impacts on education, environment, energy, and the economy. The PhD students will gain from extended industrial experience in corporate R&D and design/production environments. Wastage in the production of foodstuffs will be reduced, which lowers both energy costs and pollutant emissions. Spray drying production efficiency will be enhanced, which lowers costs, thereby strengthening the US competitive position. The end result will be immediately useful design tools for the food processing industry.