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Inquiry of Practical Design Formula for Fire-tube Boiler.....
3

Inquiry of Practical Design Formula for Fire-tube Boiler.....

Inquiry of Practical Design Formula for Fire-tube Boiler.....

(OP)
Helle,

I have to consider a new boiling system such like fire tube boiler.
Usally, Boiler boils water only.
But, My item is NOT to boil WATER.
(may be, Commercial software for Fire tube boiler is not available.)

Due to This reason, I would like to get All Formula needed for Fire tube boiler.
After getting the source, I plan to make design sheet in EXCEL format.

Is there any reference book for Fire tube boiler?
The source should be practical and reliable...

Give me a help.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

Google vaporizer?

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

"All Formula needed for Fire tube boiler" .... and no please or thank you

MJCronin
Sr. Process Engineer

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

Amazing what search engines come up with ... and quite likely, what the OP is looking for is not a "freebie".
https://www.bing.com/ck/a?!&&p=26141e8334d...

Converting energy to motion for more than half a century

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

(OP)
Thank you for your reply, Pierreick

Fired Heater is just like Water-tube boiler.
The construction of Fired Heater is totally different from that of Fire-tube boiler.
(For Fired heater, Flame is outside tubes.
But, for Fire-tube boiler, Flame is inside tubes.)

See Fire-tube boiler construction as below.



RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

You're looking for an indirect water bath heater. I've looked previously and generally most information is empirical or CFD - you're not going to get a step by step guide on how to design on. FireCAD is commercial software which can do Fire Tube boilers in hot water only service as well.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

Quote:

For Fired heater, Flame is outside tubes.

Really?

Always?

In my experience a "fired heater" that has the heat source [flames, hot gases] on the outside of the tubes is called a water tube boiler.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

API 12K may be useful, but the design heat transfer flux rates stated therein are possibly not valid for this case where you have a boiling liquid on the outside of the tubes. To check, run a full manual calc to derive heat transfer coeff for the radiant and convective components of the inside htc, and the boiling htc on the outside. In the larger API 12K heaters, there is a firetube-radiant lower bank with larger dia firetubes on the 1st pass, and a convective-radiant upper bank with much smaller tubes/ pipes on the return pass. As always, DQ Kern's Process Heat Transfer book will have most of the guidance required for this calc. This book is out of print and not available in many countries, but there it is still in print at McGraw Hill-India.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

(OP)
Dear Georgeverghese

API 12K is for Indirecting Firing Heat Transfer.

Boiling is essential for Distillation Process.
Fire-tube heater is for Distillation process.

In industrial Area, Steam is very useful to run Distillation Process.
But, to make steam, we have to expect more fabrication cost and operation cost.

I want to minimize All cost.
If the directing firing such as Fire-tube boiler is acceptable, we can reduce large cost.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

You have to consider more than design consideration to fabricate boilers in America and Western Europe. Quality control based on the NB/ASME specs is one aspect if you intend to fabricate boilers in the parts of the world that I mentioned. In China you probably could get away with it .

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

Would guess API12K water bath heaters may be cheaper for lower steam pressures ( say up to 50psig MOP? ), and direct fired ( firetube ) heaters for > 50psig MOP.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

(OP)
Dear Georgeverghese

We have to consider Boiling Process!!
It means that High Temperature should be given to Process Fluid.

We can consider steam!
But, To satisfy Boiling Process,
We have to consider High pressure steam!
It means that high operating cost and fabrication cost be expected.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

What temperature does the "boiling process" in your plant require? Steam is an efficient heat transfer medium I agree, much better than hot oil. Without being specific, you cannot expect feedback that suits your needs.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

(OP)
Dear Georgeverghese

Nitric acid solution needs to be treated in Distillation process.
Nitric acid is to be concentrated by 30%.




Thanks to feature of Vapor curve of nitric acid,
From Top of distillation tower, Pure steam will come out.

My plan is to insert Fire-tube boiler into bottom of distillation tower.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

So from column bottom, you have a reboiler operating with approx 0.3 mole fraction HNO3. Do you have a "once through" reboiler, or is it a forced recirculation type reboiler or a natural thermosyphon type reboiler. Only for a once through type will the exit temp from the reboiler match this VLE curve at 0.3mole fraction HNO3. For recirculation type reboiler, reboiler exit temp will be much higher. What type reboiler do you have, and is the column operating pressure similar to that for this VLE curve ?

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

(OP)
Dear Georgeverghese

Forced or Natural Circulation Reboiler is operating with Steam!!!
My concept is to operate Distillation Process without Heating medium, Steam.
In stead of STEAM, Direct Firing with Fire-tube boiler in Bottom of Distillation tower.

I don't know it exectly.
But, The steam is very efficient heating medium.
With very large boiler system, Plant Owner produces Massive Steam and use it as heating medium for all processes.

But, My plant is very small one. There is no need to produce massive steam.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

So what is your heating duty? Do you know what exit temp is required, and has this exit temp been verified by process simulation for the type of reboiler you've got ?
If the heating duty is small, an electrical bundle heater in a kettle once though reboiler is also an option - no risk of hot spots like you have for direct fired small heaters.
I see from the internet you are operating close to the azeotrope point for HNO3-water.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

(OP)
Dear Georgeverghese

I also consider Electric Heater in Kettle shell.
That's for very small scale of the system.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

A kettle type once through natural circulation reboiler is from a process design perspective, a safe design since the return line is not 2 phase vapor liquid which is prone to errors in pressure drop estimates. Also a wide turndown in flow to the column is possible since 2 phase flow turndown problems in the reboiler return line is avoided.
Think you may have to avoid any forced recirculation reboiler configuration since the column bottoms composition is close to the max boiling azeotrope point.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

(OP)
Dear Georgeverghese

Thank you for your confirmation for feature of Kettle type reboiler.

The turndown ratio of Kettle Reboiler needs to be large, Isn't it?

Thank you for your confirmation.

RE: Inquiry of Practical Design Formula for Fire-tube Boiler.....

Turndown on heat duty in a once through kettle reboiler is only limited by the control turndown limit of the heating device. For thyristor controlled electric heating bundle, turndown is not an issue at all.
My previous comment is not correct:
"Think you may have to avoid any forced recirculation reboiler configuration since the column bottoms composition is close to the max boiling azeotrope point."

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