Spray drying is a method of producing a dry powder from a liquid or slurry by rapidly drying with a hot gas. This is the preferred method of drying of many thermally-sensitive materials such as foods and pharmaceuticals.

It is well suited for continuous production of dry solids in powder, granulate or agglomerate form from a liquid feed. Spray drying is ideal when the end-product must comply to exact quality standards including properties such as: particle size distribution, residual moisture content, bulk density and particle morphology.

Liquid material is pumped into the top installed spray nozzle by high pressure pump and sprayed into fine droplets inside the drying chamber. Heated and filtered hot air will be blown into the air distributor at the same time. The evenly and swirlly distributed hot air completely contact with the droplets for heat transfer. In several seconds, the droplets will be dried into powder and sucked out into the cyclone for discharging via exhaust fan.

THE PARTICLE SIZE CONTROL 

The dry particle size can be easily controlled by atomization(Nozzle) of the liquid feed and the design of the hot gas inlet. The correct spray dryer design and atomization technique can increase yields for products that require classification. Spray dryers can typically produce between 30 to 500 micron average particle size, in a bell shaped distribution.

THE FLOW PROPERTIES OF DRY SOLIDS 

The shape of most spray dried particles is spherical, which provides for fluid-like flow properties.  This makes many downstream operations, such as packaging, pressing, filtering, and handling easier and less costly.

THE HOMOGENEOUS SOLIDS MIXTURE PRODUCED 

Spray drying produces the most homogeneous product for multi-component solutions and slurries.  Each particle will be of the same chemical composition as the mixed feed.

THE EVAPORATIVE COOLING OF THE PRODUCT 

The heat and mass transfer during drying occurs in the air and vapor films surrounding the droplet. This protective envelope of vapor keeps the particle at the saturation temperature. As long as the particle does not become "bone-dry", evaporation is still taking place and the temperature of the solids will not approach the dryer outlet temperature. This is why many heat sensitive products can be spray dried easily at relatively high inlet temperatures.

THE SHORT RESIDENCE TIME REQUIRED 

The surface area produced by atomization of the liquid feed enables a short gas residence time, ranging from 3-40 seconds depending upon the application, which permits spray drying without thermal degradation. This allows for fast turn-around times and product changes because there is no product hold up in the spray drying equipment.

THE REDUCTION IN CORROSION POTENTIAL 

Because a spray dryer is a gas suspended process, the dryer chamber remains dry by design. Therefore, many corrosive materials can be processed with carbon steel as the primary material of construction of the spray dryer chamber, which reduces capital costs.

 Food Industry:Fatty milk powder, protein, cocoa milk powder, subsitute milk powder ,egg white (yolk), food and plant ,oats ,chicken juice, coffee ,instant dissoluble tea ,seasoning meat ,protein ,soybean ,peanut protein , hydrolysate and so forth .Sugar ,corn syrup ,corn starch ,glucose .pectin ,malt sugar , sorbic acid potassium and etc. 
Medicine: Traditional Chinese medicine extract ,ointment ,yeast, vitamin ,antibiotic, amylase ,lipase and etc . 
Plastics and resin : AB, ABS emulsion, uric acid resin, phenolic aldehyde resin, urea-formaldehyde resin, formaldehyde resin, polythene, poly-chloroprene and etc. 
Detergent :common washing powder ,advanced washing powder ,soap powder ,soda ash ,emulsifier ,brightening agent ,orthophosphoric acid and etc. 
Chemical industry :Sodium fluoride (potassium ), alkaline dyestuff and pigment ,dyestuff intermediate, Mn₃O₄, compound fertilizer ,formic silicic acid ,catalyst, sulphuric acid agent ,amino acid ,white carbon and so on . 
Ceramic : aluminium oxide ,ceramic tile material ,magnesium oxide ,talcum and so on . 
Other : Calmogastrin, hime chloride , stearic acid agent and the cooling spray .