Drytec Ring Dryers and Flash Dryers

Drytec ring and flash dryers are co-current airstream drying systems which are ideal for drying filter cakes, fibrous materials, sludges and slurries.

Function and principle of operation
Since the material is conveyed in a hot air stream where the wet material is in contact with the highest temperature gases which rapidly cool as evaporation from the product occurs, product temperatures are kept to a minimum resulting in uniform product quality and minimum thermal damage.

Flash Dryers
Flash dryers are used to produce fine granular or powdered material when short residence times are acceptable. A stream of turbulent hot air dries the product in a continuous process.

A variety of wet material feeder devices are available, optimized according to product characteristics and feed quantities. These include sling feeders (used for non-abrasive and friable materials), cold disintegrators and direct screw feeders.

The final dried material is separated from the drying air using either bag filters or cyclone technology. Two-stage collection (e.g. cyclones plus wet scrubber) is also available where required to optimise product recovery or minimise particulate emissions to atmosphere.

Ring Dryers
Ring dryers are flash type dryers which incorporate a centrifugal classifier to increase the product residence time selectively for the wetter and larger material. Within the classifier, the drier and finer particles are separated out from the air stream to be selectively returned back into the drier for further drying. The finer and drier material is removed from the ring dryer through the bag filter or cyclone collection system. Adjustment blades in the classifier allow the degree of separation to be set to optimize the dryer performance.

Ring dryers can be fitted with high speed hot disintegrators (fixed beater type mill), located within the hot air stream, to provide screenless grinding.

Ring dryers thus provide extended residence times, allowing many materials to be effectively dried which would not be suitable for flash drying.

Drytec Ring Dryers and Flash Dryers Configurations
Drytec ring dryers and flash dryers can be either directly or indirectly heated. They can be configured in open circuit (once-through drying air), partially closed circuit (majority of the exhaust air is returned back to the heater as recycle) or fully closed circuit (100% of exhaust air is recycled back to the heater, usually through a direct or indirect contact condenser for removal of the evaporated water). In addition, indirectly heated partial closed circuit systems can be provided, providing the added benefit of high humidity exhaust which can be utilised very effectively in down stream process (e.g. waste heat evaporators) where a significant proportion of the latent heat can be recovered.

Industries for flash dryers and ring dryers 

• Chemicals
• Starch and Alcohol
• Dairy
• Minerals
• Waste products

Products

• Feed materials (including DDGS and stillage)
• Proteins (including wheat and corn gluten)
• Starch
• Casein
• Inorganic chemicals
• Organic chemicals
• Minerals
• Pigments and dyestuffs
• Waste products

Evaporative Capacity profile
5 kg/h to 30 tons/h

Anhydro Spin Flash Dryers