Liquid Pipeline Pressure drop
Liquid Pipeline Pressure drop
(OP)
Hi all,
Is there a rule of thumb for the maximum pressure drop in a liquid pipeline (psi/100 ft)? I am used to sizing gas plant piping and haven’t done liquid a whole bunch.
Since liquid is an incompressible fluid, I will expect the pressure drop to not be as significant as experienced in gas pipelines. But, what is the rule of thumb when sizing a liquid pipeline?
Any assistance is greatly appreciated.
Sam
Is there a rule of thumb for the maximum pressure drop in a liquid pipeline (psi/100 ft)? I am used to sizing gas plant piping and haven’t done liquid a whole bunch.
Since liquid is an incompressible fluid, I will expect the pressure drop to not be as significant as experienced in gas pipelines. But, what is the rule of thumb when sizing a liquid pipeline?
Any assistance is greatly appreciated.
Sam





RE: Liquid Pipeline Pressure drop
Reasonable Velocities for the Flow of Water through Pipe:
Boiler Feed.............8 to 15 ft/sec
Pump Suction ............4 to 7 ft/sec
General Service.........4 to 10 ft/sec
City.......................to 7 ft/sec
Transmission Pipelines...3 to 5 ft/sec
Go to a basic hydraulics book. Try Cranes Technical Paper 410 as a reference for the above velocities.
http://www.eng-tips.com/viewthread.cfm?qid=111206
http://www.amazon.com/Fluids-Through-Valves-Fittin...
RE: Liquid Pipeline Pressure drop
RE: Liquid Pipeline Pressure drop
4 ft/sec corresponds to 1.8 psi/100 ft pressure drop
7 ft/sec corresponds to 4.9 psi/100 ft pressure drop
RE: Liquid Pipeline Pressure drop
5 ft/sec of water will give about:
6 psi/100 ft in 1" pipe
0.6 psi/100 ft in 6" pipe
0.12 psi/100 ft in 24" pipe
Good luck,
Latexman
Technically, the glass is always full - 1/2 air and 1/2 water.
RE: Liquid Pipeline Pressure drop
There are no general guidelines on pressure drop - each application is different and requires careful considerations. Different rules apply for gravity lines, pump suction, pump discharge, viscous or non-viscous liquids, etc. Sometimes the process itself requires minimization of pressure drop (e.g. to prevent vaporization of flashing liquid etc.).
See also some of the links below.
http://petroleumcorner.com/line-sizing-criteria-ph...
http://www.cheresources.com/invision/topic/16799-l... (you need to be registered in order to download attachments)
Dejan IVANOVIC
Process Engineer, MSChE
RE: Liquid Pipeline Pressure drop
Dejan IVANOVIC
Process Engineer, MSChE
RE: Liquid Pipeline Pressure drop
Pipeline is a long series of Pipes usually of large diameter often underground with few fittings & equipment's mostly Pumps & Valves mainly to control the flow, that are laid with an intention to transport any fluid whether liquid or gas over long distances or cross country.
Piping is a large series & networks of Pipes within the well defined boundaries of the plant/plot with all fittings & equipment's like Pump, Valves, Unions & other Miscellaneous items with an intention to transfer fluid from one facility to another within those boundaries as required
All the aforementioned posts are talking about hydraulics of piping.
Dinesh S SHELATKAR
Process Engineer
RE: Liquid Pipeline Pressure drop
Is there a rule of thumb - not really as there are too many variables.
As stated before what you get is a range of generally accepted velocities which you turn into pressure drop. Viscosity and temperature has a big impact on pressure drop in liquids so what is acceptable for say gasoline, might no be for heavy fuel oil.
for long distance pipelines, about 1.8 to 2.2 m/sec has proven to be the most economical between larger pipe, lower pressure drop versus smaller pipe,, higher drop. Pressure drops of about 0.5 to 1.0 bar/km would be good for long pipelines (0.2 to 0.4 psi/100')
Shorter lines the economic velocity increases.
The often quoted maximum velocities of 3m/sec and 4.6 (aka 15 ft/sec) are nothing more than guides or a misreading of e.g. API 14E.
Higher liquid velocities and pressure drops often become subject to things like liquid surge effects (aka water hammer), electrical charge etc
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Liquid Pipeline Pressure drop