Pressure drop

alberto.carrea
(not verified)
Posted in: , on 26. Jun. 2003 - 21:03

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 ?

Thanks in advance for your attention.

Alberto

Re: Pressure Drop

Erstellt am 27. Jun. 2003 - 09:08

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

Re: Pressure Drop

Erstellt am 29. Jun. 2003 - 01:33

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!

So if you are interested in more informations about dilute phase conveying, please contact me under:

schneider@enviro-engineering.de

or visit our website:

http://www.enviro-engineering.de

Allora, ciao

Klaus Schneider

Re: Pressure Drop

Erstellt am 4. Jul. 2003 - 05:42

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

Mantoo

Pressure Drop.

Erstellt am 16. Dec. 2004 - 05:00

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

TECMEN Consultant in: Sponge Iron (DRI) handling Sponge Iron DRI Automated Storage Firefighting and Root Cause Analysis Pneumatic Conveying Consultants Phone 5281 8300 4456.