## Featured Articles

Check out the latest featured articles.

## New Article

Product Viscosity vs. Shear

## Featured File

Vertical Tank Selection

## New Blog Entry

Low Flow in Pipes- posted in Ankur's blog

# "c" Factor In The Erosional Velocity Eqn As Per Api Rp 14E

This topic has been archived. This means that you cannot reply to this topic.
2 replies to this topic
|

### #1 ankur2061

ankur2061

Gold Member

• Forum Moderator
• 2,484 posts

Posted 01 July 2010 - 11:11 AM

Dear All,

The erosional velocity equation for gas/liquid two-phase lines as per API RP 14E is given as:

Ve = C / (ρm)0.5

where:

Ve = erosional velocity, ft/s

C = empirical constant (100 for continuous service and 125 for intermittent service as per API 14E)

ρm = gas/liquid mixture density at flowing pressure & temperature, lb/ft3

However these values are now considered as conservative and there are certain new guidelines are available for "C" values:

Carbon Steel: 'C' = 135 if nominally solids free (solids less than 1 pound of solid per thousand barrels of liquid); 'C' = 200 or Ve = 65.6 ft/s whichever is lower if totally solids free

13 Cr Stainless Steel: 'C' = 300 if nominally solids free

Duplex Stainless Steel: 'C' = 350 if nominally solids free

I am also posting a link for a paper from the "Society of Petroleum Engineers (SPE)" which also talks about what actually the "C" value is and how conservative the "C" values are as given in API RP 14E. This is really very interesting:

http://www.sand-moni...s/sms_pdf15.pdf

Regards,
Ankur.

Edited by ankur2061, 01 July 2010 - 11:15 AM.

### #2 fatimah

fatimah

Gold Member

• ChE Plus Subscriber
• 93 posts

Posted 01 July 2010 - 08:28 PM

Hi ankur2061

sometimes i got confused, and in my application i never consider C for erosional velocity. i always refer to Ludwig (please find file attached) for shell side case in particular. This book is from Carl Branan. this case is only for vapor phase. if for liquid i make the velocity lower as per its viscosity. i need your comment regarding this. Thanks.

#### Attached Files

Edited by fatimah, 01 July 2010 - 08:29 PM.

### #3 ankur2061

ankur2061

Gold Member

• Forum Moderator
• 2,484 posts

Posted 02 July 2010 - 02:58 AM

Fatimah,

I know for sure that you have been working as a heat exchanger specialist based on your earlier posts.

My post is related to erosional velocity in two/multi-phase flow of oil/gas/water mixtures in flowlines & pipelines. I can assure you that API RP 14E does not deal with any heat exchange applications & you certainly are confusing two totally divergent topics.

I hope I have clarified your confusion.

Regards,
Ankur.