Simulus Engineers recently completed a study of various drying technologies for a client looking to improve the efficiency and integration of their operations. The stand-out technology option was flash drying. Flash drying involves using a stream of hot air to rapidly heat feed material and evaporate retained moisture. Below are Eleven key things about flash drying to remember when considering product drying for a project.

  1. It’s fast – time in the drying column is only 2-3 seconds. A significant benefit of this fast drying time is ease of process control and absence of any lag in the system.
  2. It’s energy efficient – the discharge gas from the dryer is normally about 120C, resulting in only a small amount of energy loss to the atmosphere.
  3. Flash drying can use waste heat – the use of direct heating and ability to handle larger volumes of air make flash drying an ideal technology for using waste heat from a gas turbine vent,
  4. Very few maintenance parts – moving parts are limited to the screw feeder, a disintegrator (similar to a blower) and a few rotary valves.
  5. It’s easy to test – Simulus have a pilot scale dryer that can process 10-50 kg/h of feed material. After an hour or so set up and fine tuning on each new material, a set of operating conditions can be defined a dry material produced within a day.
  6. Less ancillary equipment is needed – a flash drying column is quite tall, normally 15-30m, and the dry solids discharge via a cyclone at the top of the column. From here solids can flow by gravity or screw feeder to their next destination or discharge silo. Most other drying technologies require some form of sealed pneumatic transport to lift the dry material into the discharge silo.
  7. Smaller footprint – due to the really short residence time of the solids, the size of the dryer is also smaller than other options. The drying column is normally less than 800mm in diameter for flow rates up to about 100 t/h (exact sizing is based on moisture content and material properties) and stands vertically. The largest footprint item is the bag house.
  8. Simple to operate – a flash dryer can easily be operated with minimal operator intervention and remote control.
  9. Lower operating cost – the energy efficiecny of direct contact heating combined with the limited number of moving parts and low operator input make the operating cost of a flash dryer one of the lowest cost options available.
  10. Lower capital cost – due to simplicity of the drying column, the small amount of ancillary equipment the capital cost of the dryer is also often lower than other drying options
  11. Simulus can provide you with an engineering design and cost estimate include a flash dryer in your new or existing facility. Simulus often work with Drytech. as suppliers of the core technology package.
Flash drying picture
Flash dryer installation