DMR Flash Dryer: An Alternative to Spray Drying

Spray drying is widely used to convert liquid feeds into powders, but it is not always the most efficient route for mechanically dewatered products. Filter cakes, pastes and high-solids slurries may require dilution before atomisation, increasing the amount of water that must subsequently be evaporated.

The DMR flash mill dryer offers an alternative for suitable products. It accepts mechanically dewatered feed and combines drying, milling and classification in one compact, continuous process. This can reduce evaporation demand, simplify the process line and produce a fine powder with controlled particle size. The most suitable technology depends on the feed properties, required powder characteristics and production capacity.

The DMR continuous flash mill dryer is particularly suitable for mechanically dewatered feeds that require drying and particle-size reduction in one continuous process.  

• Integrated process: Combines drying, milling and classification in one unit, converting damp feed into a fine powder with a controlled particle-size distribution.
• Reduced evaporation demand: Processes filter cakes, pastes and high-solids slurries without dilution solely to create a pumpable feed.
• High inlet-air temperatures: Depending on the product and system configuration, inlet-air temperatures of up to 650°C can support rapid drying with short residence times.
• Compact configuration: Integrating several process steps can reduce the number of separate machines, material transfers and required installation space.
• Adjustable operation: Air temperature, rotor speed and classifier settings can be adapted to the feed properties and required powder characteristics.

How the DMR works

A twin-screw conveyor meters the feed into the milling chamber. The high-speed rotor breaks up the material and increases its surface area for rapid heat and mass transfer. Heated process air dries and transports the particles towards the classifier. Fine, sufficiently dry particles leave the process, while coarser or wetter particles remain in the chamber for further processing.

The compact, modular arrangement provides access for cleaning and maintenance and can be configured for different feed materials, capacities and product requirements.

Energy-efficiency features

• Mechanical dewatering: Removing water before thermal drying reduces the amount that must subsequently be evaporated.
  
• Heat recovery: Depending on the system configuration, energy from the exhaust air can be used to preheat the incoming process air.
  
• Rapid heat transfer: Dispersion by the high-speed rotor increases the exposed surface area and supports short drying times.
  
• Integrated processing: Combining drying, milling and classification reduces the need for separate machines and intermediate product transfers.