Re: Conveying Cement
Dear John,
This is pneumatic conveying and therefore there are multiple answers for one question.
Conveying cement through an 8” pipeline can be done in more than one way.
-A single diameter pipeline:
To keep the cement in suspension, the air velocity along the pipe wall must be above the local suspension velocity of the cement.
An 8” pipeline has an internal diameter of 203 mm
Using a compressor with a displaced volume of 0.5 m3/sec (FAD} results in a begin air velocity of 5 m/sec and an end air velocity of 17 m/sec.
This, when the compressor conveying pressure is 2.5 bar
When the conveying pressure becomes higher, the compressor displacement must be increased, in order to keep the cement in suspension in the beginning of the pipeline.
For lower pressures, the airflow can also be lowered.
-A stepped diameter pipeline:
To keep the cement in suspension, the air velocity along the pipe wall must be above the local suspension velocity of the cement.
A 6”/8” pipeline has internal diameters of 154/203 mm
Using a compressor with a displaced volume of 0.39 m3/sec (FAD} results in a begin air velocity of 6.8 m/sec and an end air velocity of 13 m/sec. (minimum required air flow at atmospheric pressure for cement in an 8" pipe)
This, when the compressor conveying pressure is 2.5 bar
For higher pressures, the pipe diameter step has to be adapted.
For lower pressures, this airflow is maintained.
See also:
Pneumatic conveying, Performance and Calculations:
https://news.bulk-online.com/?p=65
Dense phase- or dilute phase pneumatic conveying:
https://news.bulk-online.com/?p=238
Pneumatic conveying, turbo- or positive displacement air mover:
https://news.bulk-online.com/?p=309
Energy consumption per ton of a pneumatic conveying system:
https://news.bulk-online.com/?p=331
Pneumatic conveying, an unexpected relationship.
https://news.bulk-online.com/?p=445
Pneumatic unloaders: Problems to avoid
https://news.bulk-online.com/?p=74
Influence of electro static charge on pneumatic conveying.
https://news.bulk-online.com/?author=15
Have a nice day
Teus ■
Teus
Conveying Cement
How much air do I need to transport Cement powder along a 200mm diameter pipe. After trawling through this site I eventually came across an engineer by the name of Amrit Agarwal who had helped someone with a problem similar to my own.
I must admit to being completely surprised at the speed he came back to me in, and I can only say the help he has given me in supplying a pdf of his calculations has been invaluable.
I got it on Friday and couldn't put it down all weekend. Now its down to me to use the information to complete my project.
Once again a big thanks for the information.
John ■