×
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

Heat losses in heated tank
2

Heat losses in heated tank

Heat losses in heated tank

(OP)
Hi guys can you help me out

in my plant due to a problema with an heat exchanger, that we are buying a new one right now, we now have to heat up a tank in order to start up the UNIT and we also have to heat it up at least twice a day for an specific operation, I want to calculate the cost of this situation to bump the heat exchanger acquisition to the top of the list.
The two main problems are the heat losses through the Tank Walls and the heat required to heat up the piping to the reactor, so you can imagine the heat losses in piping are huge in a start up if the fluid leaves the tank at 60ºC it gets to the reactor at 30ºC and that's a no go, in the place of the old heat exchanger we have for now a tubular one but it just can't do the job

Fluid: Rapeseed Oil
Temperatures: heated from 15ºC to around 60ºC
Room Temperatura: 10ºC
Tank - Carbon Steel
Tank Height - 6 m
Tank Diameter - 3,8 m

I don't want you to do the job for me, just help me out with the theory
What kind of calculations would you need to do to give a estimate of the heat loss? because we have losses by conduction, convection and radiation (but I think we can discard radiation for simplification purposes) over time, meaning we heat up the tubes and the tank and then it continues to loose heat to the environment

Thanks,
JCSantos

RE: Heat losses in heated tank

Do you need to keep the entire tank at a certain temperature, or is it sufficient to provide a heater on the discharge line to the Unit/process (presumably pumped)?

If there is no need to maintain oil temperature in the tank at a certain value, obviously providing pump suction heater is the most effective solution - it is a straightforward decision. Read an interesting discussion at: http://www.cheresources.com/invision/topic/22536-s...

Dejan IVANOVIC
Process Engineer, MSChE

RE: Heat losses in heated tank

You have desired tank liquid temperature, and tank liquid starting temperature.

But heat losses are dependent on the outside air around the tank. You need that temperature, plus you need to know if it is constant or changing.

Any daylight (sunlight) heating sources?

Are the suction pipes to the pump insulated?

What was the old HX capacity?

RE: Heat losses in heated tank

Are we dealing with batch or with continuous flow process?

RE: Heat losses in heated tank

It seems this subject comes up again and again. I suggest you to trying to put your hands on "Predict storage-tank heat transfer precisely" by Jimmy D. Kumana and Samir P. Kothari (Chemical Engineering March, 22nd 1982). It represents an exhaustive dissertation on this subject with a worked out example.

RE: Heat losses in heated tank

Well spotted IRstuff, it's exactly the issue I was making reference to.

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