×
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

Latent Heat of Vaporization and Molecular Mass of Vapor for Asphalt/Bitumen and Used Motor Oil

Latent Heat of Vaporization and Molecular Mass of Vapor for Asphalt/Bitumen and Used Motor Oil

Latent Heat of Vaporization and Molecular Mass of Vapor for Asphalt/Bitumen and Used Motor Oil

(OP)
I'm looking at designing emergency venting for two different tanks, one for asphalt/bitumen storage and one for used motor oil storage. In order to design the venting I need the Latent Heat of Vaporization and Molecular Mass of Vapor for both liquids.

I scoured the internet and haven't come up with anything definitive. I did come across the Vetere Model for the Latent Heat of Vaporization of Pure Hydrocarbons = 4.1868*T *(9.08+4.36*log(T)+0.0068*T/M+(0.0009*T^2)/M) T = Boiling Point in Kelvin M = Molecular Mass of Liquid Not sure if this is accurate since asphalt and used motor oil are composed of innumerous types of hydrocarbons with great variation in boiling points and molecular weights.

I don't need exact numbers, just need to be reasonably accurate and conservative. Is there some kind of database or equation?

P.S., I have no access to any software that would do this analysis.

Any help would be greatly appreciated. thank you

RE: Latent Heat of Vaporization and Molecular Mass of Vapor for Asphalt/Bitumen and Used Motor Oil

The data you are searching for seem to be trivial factors compared to others that will affect the vent sizing, such as rain cooling the tanks suddenly.

RE: Latent Heat of Vaporization and Molecular Mass of Vapor for Asphalt/Bitumen and Used Motor Oil

Since you're asking about the Hvap of this material, I assume you're performing calculations for a fire exposure case. Before proceeding with that design, consider the temperature at which this asphalt/bitumen boils and consider the likelihood of the tank will remaining intact, since the wall temperature will be even higher than the boiling T. There's obviously no point in sizing a relief device for a scenario which causes the tank to fail, with or without that relief device.

RE: Latent Heat of Vaporization and Molecular Mass of Vapor for Asphalt/Bitumen and Used Motor Oil

(OP)
Compositepro,

I'm designing per API 2000 which specifies two types of venting, normal and emergency. Normal venting includes provisions for tank fill/discharge and thermal effects, the latter is what you're referencing with a rain event on a warm/hot tank.

Like don1980 assumed, I need the Latent Heat of Vaporization and Molecular Mass of Vapor for emergency venting due to external fire, which is generally significantly higher in terms of required relieving flow capacity.


don1980,

That's definitely something to consider. I believe the shell/roof above the liquid level would fail first before the shell below, which could be before the contents boil.

RE: Latent Heat of Vaporization and Molecular Mass of Vapor for Asphalt/Bitumen and Used Motor Oil

When exposed to fire, the liquid in the tank doesn't provide any significant cooling protection for the shell unless/until that liquid starts to boil. Once boiling starts (which occurs at the inner wetted surfaces of the shell, the Hvap helps limit the temperature of the shell metal (Hvap removes heat which is then expelled from the tank through the relief device).

In the case we're discussing, the shell below the liquid level isn't significantly protected because of the low rate of heat transfer between the shell and the liquid. The shell temperature (even in the wetted section) continues to rise unabated, because there's no boiling. And, because of the extremely high BP of this liquid, the tank is going to fail before boiling can start to occur.

Yes, the shell above the liquid level will be at a higher T, but the lack of boiling in the lower shell renders this difference insignificant.

Focus your attention on other layers of protection, those that can effectively provide some degree of protection (e.g. water spray, fire resistant insulation), rather than wasting time trying to size an emergency vent which doesn't provide any meaningful protection regardless of its size.

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


Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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