7 replies to this topic

[Jmurphyche]

I believe it is common practice to have the hot oil enter the bottom nozzle on and exit through the top. If instead I had the hot oil being used to heat a vessel by flow in through the top nozzle and out the bottom on a half pipe coil jacketed vessel would that cause any issues? The hot oil system uses a blanketed expansion tank.

[Mahdi1980]

Hi,

At the first view there is no problem and it might be well to enter from top and go out from bottom.

However, when we look into the issue deeply, we may realize that it should be vise versa to let the air come out from the vent of the oil pipeline especially in commissioning of the equipment and start up, sine the jacket is full of the air and it should be released at the top vent to let the oil do its transfer function very well.

 

hope it helps you

[Jmurphyche]

 

As long as I have vents at the high points for use during filling the system I would think that would suffice? I had the setup planned enter top exit bottom to have the flow match that of natural convection but that seems to be a bad idea.

[Mahdi1980]

Please take note, the high vent points are not just only for the filling steps.

They are utilized at the start up, I mean the operation is established and your system is in service. During the operation at the initial hours, venting and releasing the air will be just possible when the direction is from bottom to top.

[fallah]

 

Hi,

 

Please upload a simple sketch of the system you described...It will help to provide much proper response...

[breizh]

hi ,

I've attached some literature and you may use Google to find more information about Hot oil and systems .

 

http://www.heat-inc....ts brochure.pdf

 

Breizh

[Art Montemayor]

Jeff:

 

I did this for many years.  My response is to heed what Mahdi1980 and Fallah have advised.  Mahdi1980's response reflects all of my experience in design, installation and operation of processing equipment for over 50 years.

 

Feeding any liquid through a top nozzle always introduces operating problems.  The first important problem is that you can't immediately start up the system because of the accumulation of air or inerts in the top of your hot oil.  As you state, you can incorporate vents to purge out the air....... But do you seriously intend to make operators do this EVERY time they start up the unit?  Where are you going to purge the hot oil+air to?   It's a pain in-the-you-know-where, and a safety hazard as well.  I would never recommend it as an operating practice; it is much easier to always introduce your incoming liquid fluid at the bottom of any receptacle - it automatically fills the receptacle 100% with liquid (which is mandatory if it is to transfer the heat required) and purges all troublesome accumulated gaseous inerts and air out of the system.

 

It would help to discuss this topic if you told our members what you perceive as an advantage to feeding the hot oil at the top nozzle rather than at the bottom, together with a detailed sketch of the application.

[latexman]

Art,

 

Reading between the lines, it sounds like it may have been an . . . OOPS.