×
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

Line Heater Sizing

Line Heater Sizing

Line Heater Sizing

(OP)
Ref Thread:

I am newbie in sizing Line Heater. I went through this thread798-204110: Line Heater Siizng thread which is closed now. I hope there are many of you who size the line heaters using Excel spread sheet or other software's on a regular basis. Any help is greatly appreciated. If anyone has sized it using Promax software, please let me know.

I have the following information:

Gas Flow rate: 6MMSCFD
Oil Flow rate: 120 bbl/d
Preheat Coil Inlet & Outlet Temp.: 60 & 156 deg F
Reheat Coil Inlet & Outlet Temp.: 56 & 80 deg F
Bath Temp.: 185 Deg F
Operating Temp. Preheat: 2500 Psig
Operating Temp. Reheat: 250 Psig
Bath Composition: 50/50 TEG/Water

I appreciate any kind of help...
 

RE: Line Heater Sizing

Can you get us some more details on oil and gas properties?  Just simulate on Promax - this one would take no time at all.

RE: Line Heater Sizing

(OP)
Thank you Maddocks

Here are Oil & Gas Properties:

Oil:
Specific Gravity = 0.8
Molecular Weight = 170lb/lbmol

Gas:
Components                Mol%
Methane         = 85
Ethane            = 8
Propane        = 5
i-Butane        = 1
n-Butane        =1

I don't know how to incorporate Preheat and Reheat coils together in a single heat exchanger along with Fire Tube.

This is how I have been trying in Promax:

-I put a mixer to mix Gas & Oil and connected the Outlet to the Tube side inlet of first Heat Exchanger
-I connected the Outlet of tube side to a J-T Valve (to reduce pressure)
-Then I connected the Outlet of Shell side (TEG/WATER) to the Inlet of second Heat Exchanger and Outlet of J-T Valve to the Inlet of Tube side.
-So I get my Heat Duty required for both Heat Exchangers.

But I don't know how to decide on No. of PASSES, Required Coil Length, Area Required for both Coils, etc. because I have on them on two separate Heat Exchangers.

Also, how do I size Fire Tube? Please advise me....

Thank you in advance.
 

RE: Line Heater Sizing

Oh man, you're really getting into the details on this one.  Your best bet is to do a multi-block simulation and not worry about the shellside of the heater.  If you really need to get into coil sizing, you should contact a fabrication contractor or a consulting group.  This is a little complex and tends to be a fair amount of trial and error.  For firetube sizing, I usually start with a flux of 10,000 btu/hr ft2 and then adjust slightly to examine my L/D.  You can do the preheat coil as 1 block like you described followed with the reheat block and then just add the duties together for your total heater duty.  Add a fairly good margin like 15-20% to account for some heat losses, calculation issues, and changing conditions.  Installing too small a line heater will be embarrassing.

RE: Line Heater Sizing

(OP)
Thanks Maddocks.

I do the same way how you suggested. Now my concern is Coil sizing. I really need to know this as Line Heater sizing  is going to be part of my job. I need to survive!!!

Thanks again.

RE: Line Heater Sizing

here's the answer from the teachers :

the duty is 1.25 MMBTU/hr

The preheat requires 110 ft^2 or 10 17.5 ft passes of 2" sch 80.

The post requires 13 ft^2 or 1 pass of 17.5 ft of 3" sch 80 pipe.

The fire tube is a single 16" U tube of 17' by 2.


 

RE: Line Heater Sizing

(OP)
Thank you very very much DCASTO.

How did you do this? Did you use any software or spread sheet calculations?

I am using Promax software and I can get the duty but I can't get the Preheat and Reheat coil length, area, passes and size. Also the firetube length. Can you please please let me know?

Thank you in advance....

RE: Line Heater Sizing

Hanover, now named Exterran has a program called Quicksize.  The program was mostly based from the charts and data in Smith Equipment's handbook.  Hanover had bough out Smith.

Here is the screen page from a Winsim where I solved the heater flas.  I just typed in the proceedure for the water bath heater

RE: Line Heater Sizing

(OP)
Thank you very much DCASTO for sharing this information. I really appreciate it. Since we have Promax to this do, I have to try with Promax only.  

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