pipe sizing and optimization

[AMJ123]

Hi,

I have to decide the size of the line for my further design.I am in Piping field.

can anybody have detail calculations for pipe sizing and optimization for line with discharge of 60 gpm and the fluid is oily waste water.

I have gone through some of the threads in this form but i am confused to decide the velocity of the fluid.

can anybody provide me the copy of API 14 E.


Thanks,
AMJ123

 

[BigInch]

For a constant flowrate, look at a velocity of between 5 to 10 fps.

At Eng-Tips, begging for specifications is considered bad form and tells us that you and your company should not be in this business if nobody can afford to buy you the specifications you need.

Independent events are seldomly independent.

 

[DRWeig]

Here's a place to get API 14 E quickly as a download pdf:

http://www.techstreet.com/products/2931

Best to you,

Goober Dave

Haven't see the forum policies? Do so now: Forum Policies

 

[LittleInch]

AMJ123, Like big bro' says - a "typical" velocity for liquids is around 2-3m/sec which in the abscence of anything else can be used to give you an initial size (he works in imperial, I work in metric...) However your final line size will depend on many things such as the pressure available, power available and relative cost difference between a large pipe with low pressure drop versus a smaller pipe (less weight and pipe cost) versus higher pump size and OPEX. Also the number of other things in the system such as filters, bends, tees all adds to the pressure drop calcs.

Are you pumping or just using gravity? Is the pipe full or is it a drain with vapour above the liquid? All of these issues will affect the pipe size and your design,are you on a platform where weight is money or on an onshore plant?

Many websites will give you pressure drop for water for different flow rates and line sizes or provide online calcualtors for differnet size options to allow you to see what your options are.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[katmar]

The effort you put into optimizing a pipe size selection should be in line with the savings that can be achieved. At 60 GPM you are probably faced with a choice between a 1.5 inch or 2 inch pipe. Depending on the length of the pipe, you could quickly get into the situation where you spend more on engineering the choice than you could possibly save by making the best choice. In general err on the conservative side. There are going to be peak flows that are not in your specification, and with time the flows could increase if the plant is successful.

Look for the long, large bore, alloy pipes and optimize those first.

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[BigInch]

Katmar, normally I'd agree with you, but how much difference in economy are you hoping to get between 1.5 or 2 inch. 2" would be a hands-down choice.

Independent events are seldomly independent.

 

[LittleInch]

As I said earlier though it depends on how far he has to go and what his available pressure drop is. If he needs to go say 500m with only a few metres head avaialble then you'de need something a lot bigger than 2" pipe... 50 m with 10 bar PD and it's a different story.

However i do agree that the big, high value, high presusre stuff is what you need to optimise first.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[BigInch]

Exactly. Economics at that size range doesn't usually come into the picture. Other parameters typically control, whatever they may be.

Independent events are seldomly independent.

 

[bimr]

Is this gravity flow or pressure flow? Are there solids present?

Reasonable pipe velocities depend on the application. There is no correct velocity for all applications. Here is a general guideline.

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

From Crane's technical paper.

 

[dicksewerrat]

Is it 'oily waste water' or 'watery waste oil'? You need the viscosity.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[AMJ123]

hi,

for my project i need to decide whether there is enough space on the pipe rack to route this line on the existing pipe rack.
since for my project the parameter i have is only the discharge of the line and fluid property.
with this two parameter i want to decide the size of the line.

 

[katmar]

To the Brothers Inch, something has got lost in translation here I'm afraid. I was trying to say (obviously unsuccessfully) that because there is so little difference in the economics of a 1.5" and 2" pipe that it is not worth spending engineering time on it. Just do it, and if in doubt make it slightly bigger. It's not going to affect the project economics. I think we all agree on this, but somehow my message wasn't clear.

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

 

[LittleInch]

Katmar,

Nothing got lost - It totally agree with you as does big bro'. I was just saying that that size work Ok if it's pumped, but if you've only got gravity, you may need to have bigger pipe, but you probably wouldn't exceed 4" or at the very most 6". I think we got a little lost in the general subject matter....

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way