INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Multi-stage Pump Discharging into a Loading Barge/Vessel

Multi-stage Pump Discharging into a Loading Barge/Vessel

(OP)
Dear All,

Please, I need your insight. We have a 7-stage Centrifugal pump, fixed speed type that is used to deliver crude into the pipeline to the Storage Terminal some kilometers away.

At the moment, the pipeine network is not functioning due to damage to the main export pipeline, which would take some months to fix due to the magnitude of the damage. In order to ensure that we produce from the flow station, we planned alternative evacuation of the crude via barging from the facility. It is expected the pump to deliver 18,000 bpd.
My concern is that is it possible to use the existing pump to deliver the crude into the barge. It is assumed that the operating pressure of the loading barge would be within 1 - 2 barg.

See attached the pump curve.

Your response is highly appreciated.

I am what I am by His grace

RE: Multi-stage Pump Discharging into a Loading Barge/Vessel

asade,

Maybe but the pump would running well off the end of the curve and is outside the allowable operating range. Because the head is much lower than what i assume the normal head the pump will try to pump a much higher flow and impeller damage due to cavitation is certainly possible.

A couple of options.

Use a VFD and operate at reduced speed so that flow is never greater than the allowable operating range
Throttle a discharge side valve to artificially increase the system head so that flow is in the allowable operating range.
Do something else or use a different pump.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

RE: Multi-stage Pump Discharging into a Loading Barge/Vessel

asade,

I forgot to include that its also possible that you may cause the drive motor to overload. Despite operating at a lower head the great increase in flow will certainly mean an increase in power required.

Regards
Ashtree
"Any water can be made potable if you filter it through enough money"

RE: Multi-stage Pump Discharging into a Loading Barge/Vessel

Ashtree is genrally correct.

The items are quite clear.
1) You cannot use this pump as it is without some significant modifications to it or the downstream system
2) Your pump will produce something like 50bar at the flowrate you want, but your loading system ( presumable only a few km if that) only requires approx. 5 barg
3) You can throttle 45 bar across a new control valve but waste a lot of energy and possibly heat up the crude by 10 C?
4) You could remove probably 6 of the 7 stages and put dummy stages in (contact the vendor) to reduce these losses
5) You could use or fit another pump for the duration of the outage of the pipeline

I would go for a mixture of 3 & 4

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Multi-stage Pump Discharging into a Loading Barge/Vessel

I'd use a VFD if possible. Head drops off to the square of the speed difference, flow drops off at 1:1 ratio. It may reduce the flowrate a little more than you prefer, but there is no modification to the pump required, and the big pressure reduction does lend itself to use of a VFD.

Say 1/2 speed, 1/4 the head, and you can run out further on the curve at the reduced speed, so additional reduction in head there.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close