Pressure Drop in Piping

_{Palm slap here.}

Compressed Air Pipe Lines - Online Pressure Drop Calculator

Thanks lyn, I also had seen this. But it is only for compressed air, not for oxygen. I could see see another calculator, but it require viscosity of gas. I got viscosity too, but at atmospheric pressure.

I can't imagine it being much different for oxygen, either the viscosity or the pressure drop.

Out of curiosity I compared that formula with the way I normally do it using Fanning friction factor etc. Using air at flow 11300 m3/h to give actual velocity ~ 10m/s, Fanning gives ΔP ~ 0.3 bar, but the formula gives ~ 0.16 bar. Unless I've dropped a cod.

What on earth is a carbon steel pipe doing carrying oxygen?

Is that a problem, if the oxygen is dry? (just asking) Aren't oxygen cylinders made of carbon steel?

And the use of this oxygen?

I don't know, he hasn't said. What's the significance?

It seems like a lot of oxygen, maybe steel-making?

Yes, carbon steel can be used very well for dry oxygen. The only limitation is velocity, normally below 10 m/s.

I agree with Slacker..... carbon steel is a poor choice of material for an oxygen system and is banned by some codes. There are safety issues here

This must be a homework problem.

This is also a huge system. What is the use for this tremendous amount of oxygen ?

Multiple steel mills perhaps ?

Using a simplified method from the Gas Processors Suppliers Association Engineering Data Book (a very good reference, by the way), and using the good ole English units I've waited 40 years for the metric system to replace 'any day', here goes (I had to convert one way, you'll have to convert back the other):

1 km = 3,280 ft 20" pipe, you didn't say, but I'll assume S/80

17 bar ≈ 350 psia Temperature, you didn't say, but I've assumed 80°F

Mol. Wt = 32 Z (Compressibility), I didn't feel like looking up or calculating, so I used 1.0

gives a Density = 1.38 lb/ft3

You didn't give flow rate, so I did 50,000 lb/hr, 100,000 lb/hr, and 300,000 lb/hr

@50,000 lb/hr, ΔP = 0.129 psi

@100,000 lb/hr, ΔP = 0.516 psi

@300,000 lb/hr, ΔP = 4.64 psi (dang, that's a lot of O2, and still not much ΔP)

This method assumes fully turbulent flow, which, with your conditions, you have by the time the flow is high enough to give significant pressure drop. Therefore, you can correct it by considering that the ΔP is inversely proportional to the density and directly proportional to the square of the flow rate.

By the way, there are carbon steel oxygen pipelines around Houston, TX from separation plants to refineries/chemical plants. I was told that they have stainless steel sections periodically for 'fire breaks'.

if you need to fix the pressure drop, you can install a big tank in the end of the pipe for all type of air and gas.

http://www.thermexcel.com/english/program/gasus1.htm

http://softwaretopic.informer.com/pipe-sizing-formula-for-oxygen-gas/

http://www.scribd.com/doc/81023942/68/Table-2-12-Selection-Chart-for-Oxygen-Manifolds

Get a copy of Crane TP-410. You'll have to read the equation description because they offer 3 or 4 equations for this.

You've run into a problem where you use both metric and english units? What are you working with?

Thanks all. Now I got an on line calculator for pipes, fittings and valves. only we need to feed pressure, temp, density and viscosity.