Download Horizontal Flare Knock Out Drum Sizing

6 Votes

Estimated sizing for flare knock out drums in MS Excel. An API 521 case is used to verify calculation. Examples included, then add your own.

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Bobby Strain

Jul 04 2012 11:16 AM

Not to take your work lightly, this is a common approach to sizing separators. However, it doesn't size anything. The user is required to "poke & hope". Furthermore, there are shortcomings in the API sizing method, and one can easily provide a drum that is too small, resulting in liquid carryover. Check how calculations are performed with good code, not spreadsheets at checalc.com. Even this is somewhat lacking. Any sizing system should do just that. And also provide the optimum size that allows the lowest cost vessel. This is almost never done.

DB Shah

Jul 20 2012 12:36 AM

Dear Bobby,

Thanks for the feedback, I really appreciate the feedback which helps to improvise.
Yes, you are right this is not a straight forward input -output sheet. I sized a drum for one of my projects. Going by API was a lengthy process. Hence reproduced my work which might ease little bit of burden for other engs.

checal.com is a helpful site, tnx.

Wheristo

Mar 26 2014 10:20 PM

Hi DB Shah-

I am new to Flare KO Drum sizing & find your spreadsheet useful to begin with. I have a comment hope for clarification. In Step 3 under tab "Main", it says "Vary HL such that vol available is >= vol req".. I compare this value with the cells they extracted from tab "Calculation". These values are "Area" instead of "Volume". Correct me if I'm wrong, but I suppose that the step 3 in tab "Main" should probably say "Vary HL such that area available is >= area req", instead?