×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

Mixture flammability calculation

Mixture flammability calculation

Mixture flammability calculation

(OP)
I´m running a simulation of a purifiaction process, where I have,oxigen, propane, propilene, propilene oxide and methanol at the top of the distillation column.
I would like to know if there is any formula or graphic to calculate de flammability of this mixture at pressure and temperature conditions.
How can I calculate the maximum percentage (w) of oxigen allowed in the mixture to work on safety conditions.
Any suggestions...?

RE: Mixture flammability calculation

Le-Chartelier Rules of mixing:

   1/Qm = Sum (yi/Qi)

where Qm =the flammability of mixture
yi = flammability of individual component
Qi = flammability of the individual component.

RE: Mixture flammability calculation

Looking into the Loss Prevention in Process Industries by Frank Lee,  
increase the temp increases widen the gap between LFL and UFL.
increase the pressure widen the gap between LFL and UFL event more.

How much oxygen do you have in the system? The oxygen content also affect the flammable limits.

The flammable limit equations (LFL & UFL) as the function of the temp are provided in the above ref.

 

RE: Mixture flammability calculation

SooCS is absolutely right. MOCs (minimum oxygen concentrations) are proportional to LFL. LFL drop with higher temperatures, widening the flammability range. Thus at higher temperatures the MOCs also come down.

Peroxides have a lower activation energy or higher chemical reactivity. As an example ethylene oxide explodes when contaminated by ammonia. I'd recommend to carry out explosivity tests to gather data on the various vapour mixtures likeable to be encountered in the plant. There are apparatus for such testing that measure the pressures and temperatures as function of time, developed upon ignition by a spark. I pressume there are companies offering this service.

Besides, on condensation, mists having droplets of diameters lower than 0.01 mm act as vapours regarding flammability, and are of more concern if the droplets accumulate static electricity.

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!


Resources