what is pigging?

[contr0lsfreak]

Starting a project and I keep running across references to "pigging" and "smart pigging" in fuel piping system manuals. What is this?

 

[zdas04]

"Pigging" is the process of causing a solid object (the pig) to traverse a line. There are many reasons to run pigs, some of them are:
1. Run a smart pig to evaluate the condition of your line (i.e., the pig contains sensors that can record wall thickness, postiion in 3-space, etc)
2. Pigs are run to separate different fluids (or runs) in a product pipeline.
3. Pigs are run in gas pipelines to remove accumulated condensation.
4. Cleaning (or "Brush") pigs are run in lines to scrape off accumulated solids.

Pigs come in many shapes and materials.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The Plural of "anecdote" is not "data"

 

[codeeng]

Here's one example of many on the net:

http://www.piggingassnppsa.com/about.htm

 

[Guidoo]

By the way, one explanation I heard about why these spheres or scrapers are called "pigs" is that the noise produced when the sphere passes resembles the screaming of a pig...

 

[BobPE]

Guidoo:

I will second that explanation, I heard that too.

BobPE

 

[Guidoo]

This subject has been discussed extensively in thread481-62927.

 

[hbw]

They are called pigs because some are oblong, resembling the body of a pig

 

[25362]

BTW, when hydrocarbon streams are sequentially transported in pipelines (naphtha=>kerosine=>gas oil=>kero=>naphtha) without separating pigs, is it true that this is done by "using" special Re numbers to minimize intermixing ?

The meaning of these turbulent-flow "critical" Re values is that higher and lower values would increase mixing. And they apparently depend on the diameter of the piping in question.

Any comment ? Thanks.

 

[Latexman]

In the Middle East or a predominantly muslim country, is "pig" or "pigging" acceptable lingo? If not, what's the right words?

Good luck,
Latexman

 

[zdas04]

Latexman,
I read Pipeline & Gas Technology's "125 years of Pipelining" (a lot of really interesting stuff in there)this morning and it says that the term "pig" is used interchangably with the term "scrapper". My guess is that cultures that find pork products offensive use the "scrapper" term.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

The Plural of "anecdote" is not "data"

 

[dwedel]

Controls,

What type of fuel piping lines are you talking about? I didn't realize that the short runs to fueled equipment were pigged? I guess I am learning something new here. Could you explain your aplication to us a little more?

Thanks
dwedel

 

[Guidoo]

Other words for "pig" are "sphere", "scraper" or "scrapper". However, also in some muslim countries the word "pig" is used without problems.

 

[DrillerNic]

dwedel- I think controls might be talking about cross country multi product pipelines...

25362- the multi product pipeline that I helped to design & build didn't use pigs to separate our products (diesel, kerosine, LPGs, two types of petrol). We did a lot of hydraulics modelling (whihc I'm afraid I wasn't involved in) to work out the size of the interface between each product (bearing in mind the different product specifications, ie the diesel and the petrol tended to have a wider product specification than the Kerosine & the LPGs) and then draw up a list of which products could be moved next to each other. At the the tank farm at the other end was a pretty sophisticated switching manifold, to direct the interfaces into the correct storage tanks. We got the algorithms for calculating the inteface sizes added to Pipeflo, from Neotec.

And Zdas I always smiled when Aramco called a pig a scraper, mainly because it produced the tautology of running "Scraper scrapers" in the pipe...

 

[jmw]

Useful article here:

http://www.flowcontrolnetwork.com/PastIssues/oct2001/1.asp

JMW

http://www.ViscoAnalyser.com