Low BTU flaring 1

[Trond]

Is there an easy way to calculate how high a N2 (or CO2) concentration one may have in a gas stream before flaring becomes impossible? Calculating calorific value is easy enough, but it does not tell me when I reach the LEL.

Cheers!

 

[owg]

This is a quote from page 487 of Lees book Loss Prevention in the Process Industries.

"For many flammable gas-air systems, the mixture can be rendered nonflammable by the addition of about 30% of carbon dioxide or about 40% of nitrogen."

Percents are mol or vol % based on the contect. Ethylene requires 50% nitrogen or 41% carbon dioxide. If you want to calculate the numbers see NFPA 69.

HAZOP at

http://www.curryhydrocarbons.ca

 

[JLSeagull]

http://www.trainex.org/web_courses/...iles/Subpart AA Standards pdf docs/Flares.pdf

http://edocket.access.gpo.gov/cfr_2003/julqtr/pdf/40cfr60.18.pdf

For compliance with US 40 CFR 60.18, many companies add a process gas chromatograph to the flare line with controls to add fuel gas during low btu conditions. The fuel gas is added to assure greater than 11.2 MJ/scm (300 Btu/scf).

 

[Trond]

Thanks a lot, guys - that was exactly the info I needed!

 

[Flareman]

Trond

Jumping in a little late here. Download my paper "Improving flare design" from

http://www.geocities.com/flareman_xs

navigate to "main index:downloads".
There is a procedure in there to determine flammability for any inert flammable mixture.
(and my opinion about application of arbitrary rules such as 300 Btu/scf)

David

 

[Trond]

Cheers, David - a great site you've got there, which I have now bookmarked for future reference!