Operation of a Fluid Bed Drier 1

[bsg]

When you start a FBD with ,say some initial water content, there is always a tendency of ball formation ( of various size)initially.These balls contain much higher moisture than the rest of the mass and are rather difficult to dry.

In normal operation the operator runs the unit initially for some time, then take out the container and grinds the balls ( or speheres?) manually or by other means and then again put the mass for heating/drying.

This ,however, may not be desirable as the operation induces dusting and manual contact.

Can somebody tell me whether there is a better way to operate a FBD ?

 

[zhangbd]

As far as I know, high moisture balls maybe be due to one or some reasons as below:
1: Jam of spraying nozzle result in un-balance solution spraying in chamber.
2: Insufficient powder also cause failure formation of particle.
3: Please check your inlet fan and chamber mesh, jam mesh also could cause insufficent or unbalance flow.

 

[bsg]

Dear zhanqbad,

Thanks for the response.The formation of these balls is a Process phenomenon.At the start of drying the moisture gets evaporated near the heating surface( in this case at hot air inlet)and gets condensed immediately in the cold mass thereafter.This way a moisture rich layer is formed at the start of heating and this produces balls due to friction and subsequent attempt to follow the path of least ressistance ( spheres have the least surface area).

My question was whether there is any better way to tackle this Drying Process.

P.S. Similar Balls are also found in Rotary Vacuum Drier Operations.

 

[MedicineEng]

Did you try (if the process allows) to make a temperature ramp, in order to not have such temperature difference between cold/hot part? You can try to run some tests with a placebo.
It will take you more time, but maybe you can save it in the next step that is, I believe, manual or automatic sieving.

Hope that helps.
PR

 

[bsg]

Dear Mr, PaulRiberio,

You are very right.Following your suggestion we had advised one of our clients to have an initial run with little or no air temperature and then to increase the air temperature in steps.

It has worked and there is lot of improvement.

Your suggestion was simple; but absolutely great !

Thanks.

bsg

 

[MedicineEng]

bsg:
Not at all.

Sometimes the biggest problem has the simplest solution.

PR