Difference between revisions of "Back Mix Dryers"

The '''Back Mix Dryers''' are one kind of [[Fluid Bed  Dryers]]. These are usually used for powders that are not fluidizable  due to high moisture content. These can also be used for improving  thermal efficiency in spray dryers. Sometimes they are seen to be used  drying whey and permeate. It's typical usage can be witnessed in  connection with [[Spray Dryers]]. The moist powder enters the integrated  '''Back Mix Dryers''' where powder with lower moisture  content is already fluidizing. The product  temperature and moisture  content remains uniform throughout the  fluidized layer. By controlling  the powder layer in the '''Back Mix Dryers''', residence   time can be controlled. By controlling the amount and temperature of  the  drying air, the moisture content in the fluidized layer can be  controlled. The '''Back Mix Dryers''' are typically used  as an after dryer in integrated [[Fluid Bed Dryers]].However, it is also  used in specially designed dryers such as the lactose dryer. The  '''Back Mix Dryers''' are typically followed by a  plug-flow fluid bed for final drying/cooling.