
Industrial Spray Dryer
Industrial Spray Dryer is a technique used to convert either solutions or free-flowing slurries, in to powder particles having specific characteristics. Spray drying is the process of contacting on atomized stream to be dried with a gas stream that is at a higher temperature than the liquid stream. The higher temperature of the gas stream causes evaporation of the liquid from the droplets, forming particles.
There is a wide variety of spray dryer configurations, each insulated to a particular type of powder or feed consistency. Spray drying technology is widely applied system in the entire manufacturing industry.
Intensive research and development during the last two decades has resulted in spray becoming a highly competitive means of drying a wide variety of products.
Spray Drying Principal
Spray drying involves evaporation of moisture from an atomized feed by mixing the spray and the drying medium. The drying medium is typically air.
Design of Spray
Dryer fundamentally, the spray drying process is a simple one. However, the design of an efficient spray drying plant requires considerable expertise along with access to large scale test facilities, particularly where particles size and bulk density requirement in the dried product are critical.
The size of spray dryers on a purely thermal basis is a comparatively simple matter since the evaporation is entirely a function off the across the dryer. Tests on small pilot scale equipment are not sufficient in the face of such imponderables as possible wall build-up, bulk density and particle size predictions. It can provide primary essential information to design the spray dryer. Atomization of the feed is of prime importance to efficient drying and three basic feed devices are used extensively.
The single fluid nozzle produces a narrow, spray of fine particles. While a multiplicity of nozzles of this type are used in tonnage plants to obtain the desired feed rate.
As an alternative, the two-fluid nozzle with external mixing is used for a variety of abrasive materials. This system generally is limited to small capacity installations.
Centrifugal atomization achieves dispersion by centrifugal force, with the feed liquor being pumped to a spinning (Rotary ) disc. This system is suitable for, and generally used on, larger productions.