Calculation of Preheating Coil Length

[chem55]

Hi All..!

Does anyone knows how to calculate the Length of Preheating coil? I want to calculate it for pilot-plant.

It is made of SS and by using the pump, I'm injecting butane gas in the coil at 150 psi and 22 deg celcius. The coil is placed inside the waterbath having the temperature 40 deg cel constant.

My objective is to achieve butane temp 40 deg cel with constant 150 psi pressure so for that what length of SS pipe i have to use?

For this calculation, Do I have to assume the pipe dia? Is there any book which I can refer for my problem?

Any help is welcome..!

Best regards,
Chem55

 

[moltenmetal]

According to my copy of Perry's (and the disposable ligher in my pocket...), butane is a liquid, not a gas, at 150 psig and 22 or 40 C.

Whether it's a subcooled liquid or a gas that you're trying to preheat, the tube would have to be infinitely long since your water bath and desired outlet temperature are the same and the flow is non-zero. Furthermore, your inlet and outlet pressures are the same and the fluid is not boiling, which requires a tube of zero length.

If your desire is to feed liquid butane at 150 psig and 40 C, you'll need a hotter water bath. If your desire is to feed gaseous butane, you'll need an even hotter bath still!

Once you have the problem defined a bit better, you can refer to a copy of Holman or any other heat transfer text to figure out the approximate length of coil you need.

 

[Montemayor]

chem55 (Chemical):

As expressed in thread378-69281, I ask the question again: Is this a heat transfer question or a pipe coil length question?

Putting the same inquiry in multiple forums doesn't help you get a better answer. It only causes confusion. Also, it may identify you as a student who doesn't know how to ask the question and result in your entry getting red-flagged.

Art Montemayor
Spring, TX

 

[chem55]

Dear moltenmetal:
Thanks for giving me a valuable information. Actually, I'm going to use propane gas at 150psi not butane. As I'm going to test both gases, I was confused for pressure..! According to you, I will use Holman to solve this problem.

& Dear Montemayor:
I think you are right. This question should be in Heat Transfer forum. I came to know about this site from my friend and as I'm using this site first time, I was bit confused how to post my problem..! I will take care of this next time.

Thanks again for your kind support..!
regards,
Ronak