×
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

tank heating coil

tank heating coil

tank heating coil

(OP)
Does anyone have experience with heating fuel oil in bulk storage tanks?
I have an application where steam coils are used to heat fuel oils (#2 to #6), so they do not gel at low temperatures. I need to calculate the maximum steam temperature to which I can deliver to the heating coils such that the temperature of the coils will not scortch the oil or make it go boom.  I don't want the oil to get above 250 deg. F or so.  My steam available is 1246.8 Btu/lb (260 psia @ 470 deg. F).  I'm sure there will be some condensate in the line acting as an insulator.
ANYONE HAVE ANY IDEAS TO ASSURE THE SAFETY OF THE SYSTEM??

Thanks

RE: tank heating coil

Curve:

All you need in order to do what you propose, is a simple temperature transmitter that sends a signal to a main steam valve feeding the steam to the steam coil.  When the oil temperature in the tank reaches your set value (approx. 245 oF, the valve closes.   When the oil cools to 240 oF, the valve opens.  It's an on/off control because of the large capacitance in the tank.



RE: tank heating coil

Adding a little to Montemayor's post. Depending on your arrangement you could reduce you steam to a pressure that corresponds to the 250F temperature or slightly higher which will minimize the possibility of overheating.
This course this depends on the circulation around your heating. The more the circulation the higher this temperature can be especially when you need a high heat flux.

Our large fuel oil tank(9 million gallons) was controlled this way and it worked very well for many year until the dock boys pumped a barge of asphalt onto about 3+ million gals of fuel oil. I don't recall the type but it acted like asphalt by itself and had a tremendous amount of Vanadium that screwed up the boilers royally.

RE: tank heating coil

One thing to watch out for is the potential for localized over heating at the coil metal surface. The bulk temperature may be fine but you still get product degradation from the localized temperature.

RE: tank heating coil

(OP)
Pleckner,

You have touch on just what I am looking for.  Montemayor, your suggestion is exactly what I have seen in the past also, and look to do with this app.  However, I have quite a distance from my three sources of steam (HP, IP, & LP) The LP steam will never make it, only 15 psia.  IP steam is 260 psia @ 470 deg. F.  I can reduce the pressure, but without desuperheating, the temp remains near 420 deg. F at around 50 psia or so.
Therefore, I need a warm and fuzzy that when I heat a coil with that temp. steam, I'm not going to blow something up.

Thanks

RE: tank heating coil

Maybe a second temperature (switch?) on the steam return line? If the steam temperature gets too high - its an indication of too little heat being absorbed in the storage vessel (for whatever the reason)?

Best regards

Morten

RE: tank heating coil


I've seen heat-sensitive wax tanks using bottom coils that switched from steam- to hot condensate-heating to reduce heat flux and avoid scorching of the wax.

RE: tank heating coil

not sure what reg But I thought NFPA limits steam pressure for F/O tanks #6 to 15 PSI max...

RE: tank heating coil

Have you looked at direct fired tank heaters?  I had very good success using Infernotherm heaters in asphalt service.  Their design provides a very low heat flux density for heating heavy oils.  Check http://www.infernotherm.com.

Larry

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