8 replies to this topic

[guoyinyanliner]

​"I am currently working on the process design of a natural gas CO2removal unit using activated MDEA (aMDEA) solution. The design parameters are: gas flow rate of 77 MMSCFD, inlet CO2 concentration of 15%, and outlet CO2 concentration of ppm}. Preliminary calculations show that the amine regenerator reboiler duty is 26 MW, heated by hot oil. With such a massive heat load, a single kettle reboiler would result in an extremely large equipment size, which is causing me a major headache. Does anyone have suggestions on how to optimize this reboiler configuration

[breizh]

This may not be the right equipment!

Check for direct fire furnace for your application.

Take a look at the link, it may help you out.

Good, Better, Best: Choosing the Right Heating Method for Your Amine System

Breizh

[RealRoy]

Yes, in CCS amine reboiler tend to grow big. Although 26 MW is not excessive. Using thermal oil for heating is complicated in Amine Reboilers because you have to be careful for solvent degradation and need to check wall temperature. If possible better to switch to steam.

 

If a kettle reboiler gets very big, you can also think of Welded Plate Block Heat Exchangers (WPBHE) which work as a thermysophon. They are much more compact and vendors have references already with this. Also, there exists an international standard now for this equipment API 810.

[breizh]

Welded-Plate-Bloc-Heat-Exchangers-in-Amine-Systems-and-Sour-Water-Strippers-Niekerk-Kelvion-SRU-Budapest-2017.pdf

 

Nice.

Breizh

[Falah]

​"I am currently working on the process design of a natural gas CO2removal unit using activated MDEA (aMDEA) solution. The design parameters are: gas flow rate of 77 MMSCFD, inlet CO2 concentration of 15%, and outlet CO2 concentration of ppm}. Preliminary calculations show that the amine regenerator reboiler duty is 26 MW, heated by hot oil. With such a massive heat load, a single kettle reboiler would result in an extremely large equipment size, which is causing me a major headache. Does anyone have suggestions on how to optimize this reboiler configuration

I think the following threads will help you!

https://www.cheresou...d-optimization/

https://www.cheresou...ptual-question/

[Falah]

This may not be the right equipment!
Check for direct fire furnace for your application.
Take a look at the link, it may help you out.
Good, Better, Best: Choosing the Right Heating Method for Your Amine System
Breizh

So beneficial, thank you so much.I am always interested in your attachments.

Edited by Falah, 03 November 2026 - 03:47 PM.

[breizh]

Trying my best.

Breizh

[Plantcalckit.forums]

Some rough numbers on why the kettle gets so big. With hot oil at, say, 180 °C in / 150 °C out and the reboiler at about 125–128 °C, the LMTD is roughly 35 °C. At a kettle U of 500–700 W/m²·K including fouling, 26 MW needs about 1,100–1,500 m² — two or more large shells whatever you do.

Ways to bring it down: raise the hot oil supply temperature to widen the LMTD, but only within the tube-wall temperature limit your solvent licensor gives (RealRoy's point on degradation); split the duty across parallel shells; or go to a thermosyphon arrangement (vertical shell-and-tube or the welded plate block RealRoy mentioned), which gives a higher U and a much smaller footprint.

If you want to run the LMTD and area for different hot-oil temperatures, there's a free calculator at plantcalckit.com/tools/heat-exchanger-lmtd/ (disclosure: I'm involved with PlantCalcKit).

[Falah]

Yes, in CCS amine reboiler tend to grow big. Although 26 MW is not excessive. Using thermal oil for heating is complicated in Amine Reboilers because you have to be careful for solvent degradation and need to check wall temperature. If possible better to switch to steam.

If a kettle reboiler gets very big, you can also think of Welded Plate Block Heat Exchangers (WPBHE) which work as a thermysophon. They are much more compact and vendors have references already with this. Also, there exists an international standard now for this equipment API 810.

I think the same issue applies
to steam use.in any case, to prevent thermal degradation of the amine solvent, steam or hot oil temperatures should not exceed 350F. Superheated steam should be avoided. 50 psig [350 kPa] saturated steam is recommended. The maximum bulk solution temperature in the reboiler should be limited to 260 F to avoid excessive degradation