Temperature Effects On Fly-Ash Conveying
Dear meijden20,
My first thought would be that the pressure of the system would change rather than the capacity as the feeding should be constant, unless there is a pressure regulating system installed.
Then it depends on where the lower temperature affects the pneumatic conveying parameters.
Intake temperature of the compressor.
If the intake temperature of the compressor drops from 25 degrC to -10 degrC, the air mass flow increases (273+25)/(273-10) = 1.133 times (approx. 13 %)
That reduces the SLR of the conveying system (at constant capacity), which reduces the pressure drop.
Ambient temperature of pipeline.
If the pipe line runs through a colder environment, the air density in the pipeline could be lower, causing a higher air density and thereby a lower velocity. That could increase the pressure drop (at constant capacity) in case the conveying system is really a dense phase system.
Temperature of fly ash.
If the fly ash itself is colder, then the same effect is generated as if the same air mass through the pipe line is colder and the air density is increased. That could increase the pressure drop (at constant capacity) in case the conveying system is really a dense phase system.
All the effects can occur also simultaneously.
These considerations are referring to the pneumatic conveying itself.
However, the feeding can also be affected by a lower air volume (assuming the air mass flow is not affected by a lower compressor intake temperature)
A lower air volume passing through a pressure kettle will pick up less fly ash and a lower capacity results. However, this also causes a lower conveying pressure. Did you observe a lower pressure in the cold weather?
In general and especially in vacuum systems, the capacity increases in cold circumstances.
If you give the configuration of your system with the compressor data and vessel data and indicate the warm and cold temperature locations in your system, then I can try to calculate the respective influences.
Have a nice day
Teus ■
Teus
Re: Temperature Effects On Fly-Ash Conveying
Loss of conveying capacity may also be due to moisture in the conveying air. At these sub-zero ambient temperatures this moisture will freeze, resulting in both feeding and conveying problems.
Have you looked into it?
Regards,
Amrit Agarwal
Consulting Engineer
Pneumatic Conveying Consulting
Charleston, WV, USA
Email: polypcc@aol.com
Ph and Fax: 304 346 5125 ■
Temperature Effects on Fly-ash Conveying
Is anyone familiair with the effects of temperature (environment) on the overall capacity of dense phase pneumatic transport of fly-ash? During these cold weeks (-10 degr. C) we have less capacity (about 10%) and we're not really sure if this has a technical origin of a physical origin. Any experiences??
Hope to hear from you. ■