Scope of Spray Drying

Spray drying is rarely cost competitive with two-step dewatering and solids-drying processes.  The equipment is costly, and the addition of bag collectors for solids recovery from large volumes of exist gas may double the cost of a spray-dryer installation.  These higher costs are usually justified on the basis of some improvement in product quality, such as particle form, size, product flavor, color, or heat stability.  The major and most successful applications of spray dryers are for solutions, slurries, and pastes which (1) cannot be dewatered mechanically, (2) are heat-sensitive and cannot be exposed to high temperature and fuse unless they are dried in a dilute gas suspension, or (4) require the product to be in a powder form to fit the needs of its applications.  In spite of these limitations, spray drying is widely used in industry because of the benefits it provides to many products.

Purpose

The purpose of this procedure is to suggest a method and provide guidance for conducting and interpreting performance tests on spray dryers.