Re: Fly Ash Transport Velocity And Dropout
Dear Ductdesigner66
You can search this forum for "suspension velocity" in the section "pneumatic conveying"
and read the thread:
https://forum.bulk-online.com/showth...nsion+velocity
Depending on the size distribution of the fly ash particles, the flue gas velocity has to be designed in order to prevent saltation.
Special consideration must be given to the gas velocity at the boundaru of the flow.
Wall velocity has to be high enough to keep the particles in suspension.
As fly-ash is conveyed at higher velocities without significant abrasion, I woukd not worry too much about that aspect.
Try to get field data and - information from existing installations.
success
Teus ■
Teus
Fly Ash Transport Velocity and Dropout
I am in the process of designing a ducting system for a conventional coal fired plant. As part of the design I am sizing the ducts based on a maximum and minimum flue gas velocity. The maximum velocity is dictated by a threshold value above which significant erosion will occur. The minimum velocity is defined by the lowest velocity attained before fly ash starts to drop out of the flue gas stream and build up on the duct floor. I have been told that fly ash dropout occurs below 20 to 25 feet/second. Does anyone know of any literature supporting this assertion? I believe the numbers but would like to see some statistical and/or scientific basis for the identified values. ■