Fly ash rail car unloading

Posted in: , on 18. Jun. 2003 - 11:27

Does any one have experience about rail car fly ash unloading, regarding compressed air characteristics, humidity, for winter weather northern Europe.? Is it required to have compressed dry air up to -40, -30,-20 °C dew point?

Dennis Hauch - Freeport, TX, USA
(not verified)

Flyash Handling

Posted on 18. Jun. 2003 - 04:20


I will speak from my fly ash handling experience on the Texas Gulf Coast where the humidity is always with us.

The ideal handling system will be completely closed to the atmosphere. The railcar should be a closed (non-vented) type that will accommodate a dry air pad during transport, the pneumatic unloading system should be a closed-loop design, and the receiving hopper should also be closed.

The air in the closed system should be monitored for moisture and maintained at a dewpoint that will assure the flowability of the flyash out of the railcar and out of the receiving hopper. Provide a pad / depad makeup for instrument quality air which has normally a minus 40 degree dewpoint.

Even after all this it may still be necessary to provide a flow aid device, such as an air pad, on the railcar to get the material out.

This is my experience.


Dennis Hauch

Re: Fly Ash Rail Car Unloading

Posted on 19. Jun. 2003 - 06:55

You need to know min possible ambient temp inside/outside equipment. You also need to know max pressure inside equipment (where ash is present) - this will change dew point. The dew point of the supply air must be less than this min possible "operating" temp (under pressure/atm conditions) - otherwise condensation will occur.