3 replies to this topic

[mvbelke]

Hi,

 

API 521 recommends sizing tailpipes based on rated flow. In AFSA (flarenet), there is an additional option to use rated flow in node connected to tailpipes. It appears that this can result in drastically different back-pressures on the sources. The back-pressure tends to be higher when rated flow is not used in nodes connected to tailpipes.

 

Does anyone have thoughts or explanations on when this option would or would not be used?

 

Thanks!

[fallah]

mvbelke,

 

What do you mean by "...node connected to tailpipe..."?

[mvbelke]

Hi Naser,

 

I am referring to an option within Aspentech Flare System Analyzer (AFSA, flarenet). I have attached a screenshot of the location it resides in the program. You have the option of flowing rated flow through the tailpipes or the tailpipes and all "downstream nodes attached to tailpipes". We are hoping to understand how others are using this available option.

 

Thanks,

Attached Files

•  AFSA.jpg   86.05KB   14 downloads

[flarenuf]

hi

 

This option allows you to use the rated flow in any tee piece or other node that is located DS of the TP.

assume you have a PSV with a 3" Tailpipe  going into a tee which also picks up another 3" tailpipe from another pSV . as both PSV's are exclusive in flow the pipe DS of the tee is adequate as a 3".  this 3" line is in effect an extension of the tailpipe to both PSVs.

 

in this case both lines and the tee should be calculated for rated flow . nominating a pipe as a taiilpipe isnt restricted to just the pipe immediately DS of the PSV

 

hope this helps

flarenuf