DWT process

With a DWT = steam – fluidized bed – drying (fluidized bed drying with superheated steam as a fluidizing medium), the coal moisture can be effectively reduced to 5-15% before the gasification.

Abbildung DWT-Verfahren

Advantages of the process

  • High efficiency, small area requirement
  • Low-cost, low-pressure steam usable as a heat source
  • Coal moisture is recovered from the process and can be employed as a heating medium for the process through mechanical vapor compression
  • Further utilization options are: Heat transfer to another heat sink (e.g. heat pump, feed water) or use over an expansion turbine
  • High dust-separation efficiency, emissions are clearly below the ecological limit
  • Safe operating state (inert steam atmosphere) through closed steam circuit under slight over-pressure in the dryer

History of DWT and references

In the 1980's and 1990's began the development of the technological basics for a process for the low-temperature steam-fluidized-bed drying of coal and elutriates by UET Freiberg, a predecessor of CHOREN Industries.

  • In the 1990's: Registration of several patents and installation of different DWT systems for sludge drying (UET)
  • 1991: Design for a 55 t/h DWT coal-drying plant for China
  • Investigations for scale-up to 100 t/h
  • 2010: Conception of strategic partnerships to DWT through CHOREN Industries