Water Reclamation Using Spray Drying

Spray drying is a continuous physical separation process where a solution is sprayed into a hot drying medium. The resulting products are dry solute particles and the drying medium bearing the solvent vapor. Using one of several methods the solvent is recovered from the drying medium. The exact nature of the dried solid and recovered solvent depends on the physical and chemical properties of the feed and the design and operation of the dryer. In this paper we discuss progress made on the development of a prototype for advanced life support applications, and provide data on its purification abilities. A system processing 1 kg hr⁻¹ of aqueous brine solution consumes on the order of 1000 W, but this value was strongly tied to other processing parameters such as dryer inlet and exit temperatures and the heating mode. Analysis of recovered water having an initial concentration of 48000 ppm TDS had between 12 and 134 ppm TDS and strongly depended on the processing conditions. Analysis of fluid properties suggested dried particles can be manipulated pneumatically. Alternative heating methods may allow for processing of a vide array of feeds, precision control and high efficiency.