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Existing Line to be replaced with new line
2

Existing Line to be replaced with new line

Existing Line to be replaced with new line

(OP)
Hi,
Crude oil existing line to be replaced with new line, I have check the velocity for existing line that is 0.032ft/s. that is too low.the crude sp gr is 0.85 and line dia is 16" and 13.5 km long and total flow is 8360BPD.now company want to replace this corroded line.
can you please let me know what maximum velocity i should use for pipe dia meter calculation also pig velocity factor.
Thanks
10815L

RE: Existing Line to be replaced with new line

I think you have an extra zero in your velocity if your 8360 BPD is correct.

For liquids, I usually try to keep the velocity below the low teens if it's clean. If you have sand in the oil, you might want to reduce that velocity. The other factor to a smaller pipeline is a higher pressure required at the source to get the same flow rate through the pipeline, you'll need to consider the source pressure constraints.

RE: Existing Line to be replaced with new line

2
Max velocity defined by one of the API standards (I just can't remember which one) for errosional velocity is:

vmax=100ft/sec/(ρ)^0.5

So, for water it is generally taken as 12.65 ft/sec. For your 0.85 SG oil I get a max of 13.7 ft/sec. You don't approach that velocity until you are in 2-inch pipe.

If this were my project and I could take the 16-inch out of service for a month, I'd probably pull a 6-inch spoolable composite pipe through the 16-inch. The SoluForce 6" product has 500 ft on a spool so you would have to dig about 90 bell holes instead of 13.8 km of ditch. That would give you a non-corrosive surface and about 3.2 ft/sec.

If I had to leave the 16" in service while I looped it I'd still use a 6" spoolable composite product and see if I could get away with plowing it in (it all depends on the number of foreign lines, roads, irrigation ditches, and fence lines you have to cross).

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: Existing Line to be replaced with new line

(OP)
Hi David,
Can you explain your this quote "If this were my project and I could take the 16-inch out of service for a month, [color Red]I'd probably pull a 6-inch spoolable composite pipe through the 16-inch. The SoluForce 6" product has 500 ft on a spool so you would have to dig about 90 bell holes instead of 13.8 km of ditch.[color] That would give you a non-corrosive surface and about 3.2 ft/sec"
Thanks

RE: Existing Line to be replaced with new line

There are a lot of bits to that quote. I'll try to take it in small bites:

  • "If I could take the 16" out of service". Sometimes you can, other times you can't. That decision comes down to economics and the logistics of removing that much oil (it is something like 11,000 bbl of oil). I did a similar job in 8-inch last year and we were out of service for 25 days.
  • "I'd probably pull a 6-inch spoolable composite pipe through the 16". The class of products called "spoolable composite pipe" are made of a composite (oddly enough) of an HDPE (usually, for high temp it can be PEX) flow layer, then a strength layer that can be made of steel, kevlar, fiberglass, etc., finally there is an outer wear layer that comes in several flavors. This class of pipe has the strength of steel, but the corrosion characteristics of plastic and doesn't require welding (or welders). For steel pipe I generally figure that labor will be 60% of the job and material will be 40%. For spoolable composite I figure material is 85% and labor is 15%. I like this stuff
  • "The SoluForce 6" product has 500 ft on a spool so you would have to dig about 90 bell holes instead of 13.8 km of ditch". The technique is to dig a bell hole, cut out a section of the carrier pipe, run a cable back to the last bell hole and drag the pipe off the spool into the carrier pipe. Finally you use a pipe to pipe connector to connect the two spools. Since the spool has 500 ft of pipe on it, you have to do this every 500 ft. The people that have a 6-inch product are SoluForce, FiberSpar, FlexSteel, there are probably others, but mostly the product sheets on their web sites show 4-inch max. I've used FlexSteel and FiberSpar. A friend just did a job with SoluForce and likes it better than anything on the market.
I think that was all your questions (the part about the velocity was outside the "color" TGML, you have to use "/color" to turn it off, if you hit the red flag button on your and ask nicely, site management will add the slash for you)

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

RE: Existing Line to be replaced with new line

(OP)
David Thanks
Your time and advice for replacement techniques.
Best Regards

RE: Existing Line to be replaced with new line

Quote (Clarence Day)

Information's pretty thin stuff unless mixed with experience.

Well done, zdas04.

Good luck,
Latexman

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