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3

# Coil Surface Area Calculation

coil surface area

4 replies to this topic
|

### #1 abdelkareem

abdelkareem

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Posted 08 February 2018 - 07:43 AM

Dear all,

I have indirect gas fired water bath heater to heat compressed natural gas by using 400 KW gas burner and this gas is passing inside a carbon steel coil.

This heater is full of water with volume 10,000 L and the max. water temperature is 85 C.

The natural gas inlet is 15C and the natural gas outlet from the coil is 65C by mass flow rate is 7000 kg/hr.

kindly share with me how can I calculate the total surface area for the carbon steel coil (diameter & length) to heat the gas from 15 c to 65 C by flow 7000 Kg/hr by using 400 KW energy.

Regards,

Abdelkareem.

#### Attached Files

Edited by abdelkareem, 08 February 2018 - 07:56 AM.

### #2 Art Montemayor

Art Montemayor

Gold Member

• 5,528 posts

Posted 08 February 2018 - 10:53 AM

Abdelkareem:

First of all, your skimpy data sketch shows a simple U-tube or bundle - NOT a "coil".   Your lack of simple, accurate, and detailed basic data is going to raise a lot of questions with our experts on this Forum.  The first question is going to be:  What KIND of coil are you referring to?

• a helical coil?
• an Archimedes spiral?
• another variation?

I strongly recommend you go to: http://www.jfdcoil.c...ducts-coils.asp

Read all of the information found there and download the related type of coil data sheet, fill it in with readable script and submit it to our members in your next post here.  Also, give our member ALL of the basic data.  What fluid goes in the coil?  (I believe I know exactly what you are struggling to explain).  I've designed and built several natural gas field heaters in my time; but I want YOU to work on defining what you want or need.  You must learn sometime or somehow to accurately define what you are referring to.

I also moved your thread from the hydrocarbon Forum to here at the Process Heat Exchange Forum because that is what I believe you are trying to define - how to heat natural gas in the field.  Am I correct?  (I would appreciate a response).

### #3 breizh

breizh

Gold Member

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• 3,847 posts

Posted 08 February 2018 - 08:56 PM

Hi,

It looks like Hairpin . For the calculation I would calculate the equivalent length of the pipe and the surface area should be # pi *OD *L with L = 2 * straight pipe length + 180 bend .

Hope this helps you .

Breizh

Edited by breizh, 10 February 2018 - 01:59 AM.

### #4 abdelkareem

abdelkareem

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• 4 posts

Posted 11 February 2018 - 07:02 AM

Abdelkareem:

First of all, your skimpy data sketch shows a simple U-tube or bundle - NOT a "coil".   Your lack of simple, accurate, and detailed basic data is going to raise a lot of questions with our experts on this Forum.  The first question is going to be:  What KIND of coil are you referring to?

• a helical coil?
• an Archimedes spiral?
• another variation?

I strongly recommend you go to: http://www.jfdcoil.c...ducts-coils.asp

Read all of the information found there and download the related type of coil data sheet, fill it in with readable script and submit it to our members in your next post here.  Also, give our member ALL of the basic data.  What fluid goes in the coil?  (I believe I know exactly what you are struggling to explain).  I've designed and built several natural gas field heaters in my time; but I want YOU to work on defining what you want or need.  You must learn sometime or somehow to accurately define what you are referring to.

I also moved your thread from the hydrocarbon Forum to here at the Process Heat Exchange Forum because that is what I believe you are trying to define - how to heat natural gas in the field.  Am I correct?  (I would appreciate a response).

Dear Sir,

Regarding the sketch, it was my mistake when I expressed the coil by U tube, actually I was planning to use Zig-Zag coil but ididnt show that on the sketch.

The fuel which is inside the coil is CNG compressed natural gas (density =0.71 kg/m3) has the following composition :

Methane (C1): Mole %94.06

Nitrogen: Mole % 4.22

Carbon Dioxide: Mole %0.41

Ethane (C2): Mole %1.24

Propane (C3): Mole %0.06

1-Butane (C4): Mole % 0.00

N-Butane (n-C4): Mole %0.00

1-Pentane (C5): Mole %0.00

N-Pentane (n-C5): Mole %0.00

Standard Density:Kg/Sm30.71

Relative Density 0.58

The Max. inlet pressure to the coil is 250 barg. the Min inlet pressure is 30 Barg. regarding the pressure drop, the max. acceptable pressure drop in the coil 3 barg.

FYI, the ambient temperature is (15-50 C).

Regards,

Abdelkareem.

### #5 abdelkareem

abdelkareem

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Posted 11 February 2018 - 07:07 AM

Dear Breizh,

Thanks for your cooperation, kindly share to me the source of the equation if it's possible.

Regards,

Abdelkareem.