1. alberto.carrea Guest

## Pressure drop

Hello.

I was calculating pressure drop in a pneumatic conveying line using formulas found in Perry Chem Eng (6th ed, pp 5.46; these are the same formulas you can find in the Pneumatic Transport by Martin Rhodes: www.erpt.org/014Q/rhoe-05.htm) and I found for my case:

air vel: 15 m/s
solid/air ratio in weight: 3
pressure: around atmospheric
temperature: 30 °C
inner pipe diameter: 0.078 m
line: 100 m of horizontal pipe

the following results:
pressure drop due to air friction: around 3600 Pa
pressure drop due to solid friction: around 37000 Pa (ten times the air friction !!)

To be more sure, I checked these results with other methods available.

Using the nomograph that you can find in www.cheresources.com/pnuconvey2.shtml
I found a total (gas friction +solid friction) of around 7000 Pa (instead of 40000 Pa).

Using the method suggested by:

www.fcq.uach.mx/licenciaturas/temarios/ unitarias%20I/tema3.PD

I found:
pressure drop due to air friction: around 3200 Pa
pressure drop due to solid friction: around 3100 Pa

I start thinking that the first method gives wrong result in the solid friction contribution.

Could some one reassure me or tell me where I can find reliable fromulas for the calculation of the pressure drop in lean pneumatic handling system ?

Alberto

2. Solids pressure drop will be difficult to calculate correctly using these equations. To solve this problem, you should find out the friction factor for your solids, and then use that factor to calculate the solids pressure drop. We can help you in these calculations if you need help.

Regards,

Tim Agarwal
Pneumatic Conveying Consultants
www.powderandbulk.com/pcc
polypcc@aol.com

3. Ciao Alberto,

I agree with Tim Agarwals reply concerning pressure drop calculations in pneumatic conveying.
But nevertheless, the pressure drop you have calculated from the last two sources seems to low.

In my experience, the additional solids pressure drop should(depending on the material you will use) cover the range between 22000 and about 35000 Pa!

schneider@enviro-engineering.de

http://www.enviro-engineering.de

Allora, ciao
Klaus Schneider

4. Alberto

I am a PhD student working on prediction of pressure drops in lean phase pneumatic convening systems. Apart from conveying conditions pressure drops caused in pneumatic conveying is greatly dependent on material properties Such as particle size, density and shape. You have not mentioned the type of material you want to calculate the pressure drop for. If you give me some details about the material I might be able to help you in calculating pressure drops.

Regards

ca74@gre.ac.uk

5. ## pressure drop.

Alberto.

simplemente sigue buscando dentro de estos foros y encintraras refereb¡ncias a varios sitios que te ayudaran a calcular la caida de presion de muchos materiales . En transporte opneunatico.

tambien hay sin numero de libros y docunemtos de referencia , mi favorito es el de W C Yang, transporte pneumatico en una linea de 100 mm.

pero tambien hay excelentes libros como el de Roy marcus Klinzing Risk et all. Algunos autores te confundiran mas de lo que aclaran el asunto.

pero si te basas en Yang , Solt , Klinzing y Marcus y un poco qusas tambien Arnold encontraras la luz.

Attentamente

Marco