Software to analyze the transients of a steam pipeline

[dbevil]

I'm looking for a suitable software package to analyze the transients associated with the cold start-up of a steam pipeline. The system will have a total of 35 km of 24" to 8" in two main trunklines with 20 to 30 ea. 6" and 4" branch lines that will be from 1/2 to 2 km long. The steady-state hydraulics and line-sizing were analyzed with SimSci's PipePhase. However, concern for slugging and controlled velocities during a cold start are beyond it's capabilities.

Has anyone worked with a software package that can handle the transient case?

 

[MJCronin]

bdeveil,

"Slugging" of long steam lines at startup is usually handled by a system of steam traps and a long, slow startup procedure. Is your system operated this way ?

Are there small "bypass lines" around all valves 6"NPS and larger?

The steam system slugging as you describe is "two phase flow" which many software programs cannot handle. Most simply predict shock occuring within a compressible flow system.

Have you considered "PIPENET" by sunrise systems ???

http://www.sunrise-sys.com/trncase02.htm

There is a company called AFT that also produces a piping transient package.

http://www.aft.com/products/

Let us know more about your system and what you decide upon....


MJC

 

[ModManSEK]

I've done a limited amount of fluid flow problems with a code called SINDA/FLUINT. It will handle multiphase problems -- steady-state or transient. It also has quite a large built-in database of fluid properties in it. I'm not sure how much you are willing to pay for the software, but SINDA/FLUINT used to run around $2K to $3K for the basic package. (It may be too robust for what you are trying to do.) You can learn more about the software at

http://crtech.com/.

Good Luck!

 

[dbevil]

MJCronin,

The steady-state software I use (SimSci's 'PipePhase') handles steady-state two-phase flow in steam pipelines, but does not handle transients. I'm looking for a program that can handle the transient thermal aspects of heating up the system to steady state and predict the amount of condensate produced in the process and where it accumulates. I may have to write one myself, if nothing surfaces.

The system as designed has "drip-legs" for automated removal of condensate at major low points or every kilometer. The 6-inch lines do not have by-passes, since they are on branch lines and will not be used when the system is pressured. During a cold start, the branch lines are either open or closed. All trunkline valves that can be used while the system is operating will have by-passes capable of throttling steam.

 

[KANN]

dbevil,

This is off topic, but I'm quite interested in a drip spacing "at major low points or every kilometer". Does your company have installations where a drip occurs only once every kilometer? What steam pressure/temperature? When was the piping installed? Could you say where - US?

KANN

 

[FarshadN]

dbevil,

I know that HYSYS.Plant (

http://www.Hyprotech.com)

is used in similar projects. It is a dynamic simulator with extensive steam property packages (NBS and ASME) and two-phase flow modeling capabilities included.

It is in fact a process simulator but you can still use its PIPE operation for your two-phase pipeline. It is not cheap, though.

Another (cheaper) option is to use its steady-state version coupled with PIPESYS, a pipeline simulator package, which can model transients(slugs), as well.

rgds,
Farshad

 

[dbevil]

Kann,

During a cold start, there will obviously be more "drips" than a few a kilometer. Before steady state is achieved, about 2000 cubic meters of condensate will be formed. In this system, there is no need to remove 100% of the condensate formed during startup, since the ultimate goal is to inject the steam into an oil reservoir. The primary goal is to control the velocity of the slugs formed in the system prior to achieving its steady state condition of 600 tonnes/hr at 1500 psi and 750°F.

The system is in So. America.

 

[Tremolo]

Have you found a suitable software package to handle your steam line transient? If not, please let me know.

 

[dbevil]

Tremolo,

No, I have not found a suitable commercial package. I have started on a spreadsheet, but think it's going to take something more powerful. I have steam functions for a spreadsheet, but not for a BASIC program.

 

[Tremolo]

Dbevil,

I can e-mail you some information on a computer program with a visual basic interface that we have used to examine single and two-phase liquid and steam transient flow in nulcear power plant piping systems. The computer program will provide dynamic pressure response in the pipeline due to slugging of the fluid.

Please e-mail me at elicson@fauske.com