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Recent content by hitchhiker

  1. hitchhiker

    parallel pump problems

    Thanks. What about the recirculation line? Ideally it's better to control from individual discharge goes to common recirculation header (separate recirculation line from each pump) or take common recirculation line from the discharge header as shown on P&ID?
  2. hitchhiker

    Reciprocating Pumps

    Why don't you arrange a pre-bid meeting with all potential suppliers? In that meeting you can highlight what are the requirements, what's not and what disqualification factor would be applied for particular tender. At the end of the meeting, you would come up with MOM that have a legal binding...
  3. hitchhiker

    parallel pump problems

    another thing, would you recommend individual control valve at each pump discharge or 1 common control valve at the discharge header like the design above? Which one will work better?
  4. hitchhiker

    parallel pump problems

    @artisi, true, but is there any "rule of thumb"? we can have many, but too many? @littleinch, even at dynamic dominated system would make the addition more insignificant, with steeper system curve, am i right? Those I see here with more than 5 pumps in parallel usually on water injection...
  5. hitchhiker

    parallel pump problems

    Guys, while waiting for the data, I got another question. Is there any guide or recommended practice on number of pumps in parallel? Like for instance in my current case I have 5 pumps. Personally to me, 5 is too much because the flow addition normally quite marginal, but yet I've seen 8-10...
  6. hitchhiker

    parallel pump problems

    Guys, thanks for all the very insightful replies. I'm currently working with operation to obtain more data. Will let you know the reading once I get it.
  7. hitchhiker

    parallel pump problems

    clay87, there is only one common recirculation line from the discharge header as you can see in my previous post. each individual pump doesn't have dedicated miniflow line. let say the old pump (stronger) dominates the new (weaker), and with recirculation line the flow from the new pump goes...
  8. hitchhiker

    parallel pump problems

    Let say I have a minimum flow problem, how does a recirculation line back to the suction tank would help? because the suction tank itself have continuous incoming stream of fluid and adding back small portion from recirculation line should not make any different anyway, unless there are no more...
  9. hitchhiker

    parallel pump problems

    Artisi what are the chances that the pump experience discharge recirculation? can it have the same erosion damage on the casing even if there were no sand content in the liquid? plus we just got seal failure too..
  10. hitchhiker

    parallel pump problems

    Well, I've just got news from operation that they just got mechanical seal failure on one of the pumps. Come to think of it, is it possible that the pumps experience discharge cavitation? As I quote from one website: "Discharge cavitation occurs when the pump discharge pressure is extremely...
  11. hitchhiker

    parallel pump problems

    Sorry I forgot to explain on the pump curve, the red dot line is the old existing pump and the solid black line is the new pump. and btw here are the foto of the current casing condition with suspected sand erosion. let say when the casing di deteriorated as above, does that affect the...
  12. hitchhiker

    parallel pump problems

    BigInch, I don't really get it. System curve plotted using absolute head? Normally we only use absolute head in calculating NPSHa. And I thought suction pressure should increase while flow increase? suction pressure increase, discharge decrease ---> flow increase? please do correct me if i'm...
  13. hitchhiker

    parallel pump problems

    Thanks for the reply guys. @littleinch, when I first learned about the calculation I straightaway thought that this was really recipe for disaster, having a curve like that, and nobody notice that unfortunately. But since u said it's possible, and after hearing report that there were no...
  14. hitchhiker

    parallel pump problems

    Here is the pump-system curve correction, only 1 & 2 pumps operating in parallel dont intersect with the system. The 5 booster pumps operates 4x25%, with 1 pump standby. And here is the P&ID Any comments?
  15. hitchhiker

    parallel pump problems

    Dear fellow members, I'd like to ask your expert opinion on my current situation. I'm currently handling left-over projects that have 5 booster pumps in paralell delivering liquids from storage tank (produced water) to a pig launcher. 3 of the booster pumps are old existing pumps and another...
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