Rotary Dryers


Thermopower Furnaces is a specialist of custom designed rotary dryers focussed on our clients’ and products’ specific needs. Rotary dryers allow for continuous processing on a wide range of materials at high throughputs. Rotary Dryers evenly mix the material and simultaneously provide a material handling system from material feed to the product discharge.

Indirectly Heated Rotary Dryers

Indirectly Heated Rotary Dryers constantly mixes the material and subjects it to regulated temperatures focussed on optimal heat transfer achieved by multi-zone temperature control along the length of the rotary tube. The advantage of indirectly heated rotary dryers compared to the alternate of directly fired rotary dryers, is that the process off-gases (steam) are separated from the products of combustion used in directly heated applications. The lower gas velocity reduces product “carry-away” in the gas stream and allows for smaller gas handling equipment downstream of the rotary dryer (cyclones, baghouses, condensers,  ESPs etc.). A further advantage of indirectly heated rotary dryers is that there is no contamination with ash or the products of combustion in the dried material. This is a desirable feature when processing high purity products.

Directly Heated Rotary Dryers

Directly heated rotary dryers introduce a hot gas medium into the rotary tube where the processed material is subject to heat transfer and drying by convection. The lifter bars inside the rotary tube constantly turn the material bed over and has the product fall through the cross section of the tube while exposing the product to the hot gas stream. Convection drying achieved in Directly Heated Rotary Dryers is thermally efficient and a suitable technology where product contamination and higher levels of product “carry away” is of negligible consequence to the plant operation.

Thermopower Furnaces’ Rotary Dryers are robust, reliable and require a low level of maintenance under demanding conditions. 

Rotary Dryer Specifications 

  • Indirectly or directly heated rotary drying.
  • Co-current gas flow or counter current gas flow arrangements.
  • Controlled atmospheres if required.
  • Electrically heated, gas heated, fuel oil heated or waste gas heated (subject to availability).
  • Variable residence times (Adjustable tube speed, kiln angle and feed rates).
  • Variable feed particle sizes from powders through to granules and lumps.
  • Easily coupled with Gas Abatement equipment such as Cyclones, Baghouses, ESPs, Condensers etc.
  • Local PID Dryer Control or Remote PLC Control available. 
  • Agitation and Knocking systems available.
  • Various material feeding options (Gravity chutes, vibratory feeders, screw conveyors, belt conveyors, etc.).


  • Filter Cake Drying
  • Mineral Concentrate Drying
  • Free Moisture and Crystalline Water Removal from most powder and granular materials