Tie in point - Big diameter difference
Tie in point - Big diameter difference
(OP)
In the project that I’m involved we are now in the design phase. I’m more from quality control and assurance but I want to help. We have right now an issue regarding the tie in point of our pipeline and a pipeline of other facility. The question is that the flow rate is the same and our pipe diameter is much bigger than the one that we will tie in. This will cause a velocity problem isn’t it? How can we solve this?





RE: Tie in point - Big diameter difference
Make the pipe bigger??
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RE: Tie in point - Big diameter difference
Flow rates 1000m3/s.
RE: Tie in point - Big diameter difference
RE: Tie in point - Big diameter difference
Maybe to reduce our pipe diameter before the tie-in?
RE: Tie in point - Big diameter difference
At that rate (call it 3 BSCF/day) at a nominal 1000 psig you would have 290 ft/s in the 18 inch and nearly 1470 ft/s in the 8-inch (assuming your gas is the only thing in the line). 1470 ft/s is 1.06 Mach and it isn't happening. You would need pressure on your 18-inch well above 1500 psig (with nothing else in the 8-inch) for this to work with compressible flow calculations.
David Simpson, PE
MuleShoe Engineering
In questions of science, the authority of a thousand is not worth the humble reasoning of a single individual. Galileo Galilei, Italian Physicist
RE: Tie in point - Big diameter difference
If the flowrate is the same, how come you're designing a much larger pipe? Also, I don't understand how you can tie-in a large diameter into a small diameter. Hydraulics are not going to look good.
RE: Tie in point - Big diameter difference
We are talking about a new depot (ULP, ADO, JET and HFO), those are the dimensions of the pipelines to the new tank farm.
But we must connect the pipelines from the ships offloading directly to other private terminals and there we have the problem with the existing pipes dimensions.
RE: Tie in point - Big diameter difference
RE: Tie in point - Big diameter difference
18" line results in velocities <2 m/sec and that looks good from design point of view.
Dejan IVANOVIC
Process Engineer, MSChE
RE: Tie in point - Big diameter difference
Tuga29 - draw out your schematic and add numbers and check them - flowrate, pressures, distances then come back.
1000m3/hr of liquid in an 8" pipe is just stupid. Can be done but makes no sense and you can generate significant surge forces or static charge.
However your description is all over the place and doesn't make sense.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Tie in point - Big diameter difference
The 1000m3/h was a client requirement and today we see that it was wrong since the existing network distribution works with 500m3/h. Now we just need to see if with the cargo pumps (100 to 130m head) we could reach the furthest tank, about 8km of pipeline.