×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

LEL and UEL

LEL and UEL

LEL and UEL

(OP)
Dear all

First of all, I lack knowledge of LEL and UEL. What I know, below LEL, or 100%LEL (5% by volume), methane is too little to burn, so a flame cannot happen. And above UEL% (15% by volume), the mixture is too rich to burn or explode.

At what concentration of methane does burner support proper combustion (good air-fuel ratio) and at what point the fuel become rich and can cause an explosion?

Thanks for your help.

Aida Hannah

RE: LEL and UEL

Hello Aida, it depends...

There is most certainly a theoretical stoichiometric ratio for methane/air mixtures, but that provides little more than a starting point.

Also, the above-noted may not necessarily be the ideal ignition ratio...

Your reference to a "burner" suggests continuous combustion rather than cyclic, but is this at near-atmospheric pressure [such as in a boiler furnace] or at an elevated pressure [such as in the combustion chamber of a gas turbine]?

Properly graduated and matching adjustment of fuel admission valves and air admission dampers or equivalent is commonly achieved using flue gas analysis, and the optimum excess air ratio is determined by the application, burner style, fuel composition, firing rate, primary and secondary air temperatures, etc., etc.

More information leads to better answers.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close