[Equipment Process Design problem] Question regarding Deaerator construction...... 1

[gotothesky]

Hello,all..

I am a engineer for boiler thermal design.

For Deaerator, I would like to design with PACKING Material....
(I mean packing tower such like stripping column...)

My proposal as above is reasonable. But, nobody considers PACKING column for a Deaerator....
Is there any person who can explain why Packing column is not applied for a Deaerator..

In addition, Deaerator is needed for boiler system to remove oxygen in water that is used for the system.

I don't know exactly.... but, Packing column has simple construction.. it means that Fabrication cost of a Deaerator can be reduced with Packing column construction.
In order to make a Deaerator be high efficient, Some tray should be installed in a Deaerator as internals.
The purpose of internals is to increase contact between water & steam.
The tray is made from steel.

Thank in advance for your kind answer.....

Regards,

 

[MJCronin]

GOTO,

In a boiler plant, the Deaerator functions as a PACKAGED DEVICE designed to achieve a certain performance.

The performance that boiler plant operators want from a Deaerator is:

- Reduction of dissolved oxygen
- Reduction of dissolved CO2
- Condensate Surge Capacity

The Deaerator is NOT a device for Distillation !!!

Changing the design of packing implies a change in the distillation of a process...

Changing the "Packing" for a deaerator implies that you know better the design of the DA better than the original designer !!

When a Deaerator is purchased, it is purchased as a complete unit, with all associated equipment, designed and tested to industry standards. An experienced reputable US vendor is recommended



Purchasing of a used, third world Deaerator has frequently led to disaster. Due to problems with operational surges and hammering, internals have been damaged and the safe lifetime is limited.

Due to the retained energy of the DA, the failure of large older units have lethal and massive...

http://mmengineering.com/wp-content/uploads/2015/07/Conduit-Vol-15-No-2.pdf

https://www.energy.gov/sites/prod/files/2014/05/f16/steam18_steam_systems.pdf

https://en.wikipedia.org/wiki/Deaerator

https://deaerator.com/

What are you trying to achieve or are your questions simple idle speculation ?

Surely, this is a real project you have been assigned ....

Tell us more ...



MJCronin
Sr. Process Engineer

 

[EdStainless]

MJC, I had hoped that you had linked to some failure photos. I lost that file with my last job change. Yes they can be spectaculary bad.
The purpose of the DA is to remove non-condensable gases, and to balance feedwater flow.
The trick is to not waste steam.
If you wanted to separate the functions then maybe a tray arrangement would be good for a small DA with very low retention volume and time, but then you would need additional equipment to serve the other functions.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy

 

[Compositepro]

The purpose of packing in a distillation column is to provide contact surface area between gas and liquid as the concentrations vary going up the column. The differences in boiling point between components may be small. In a deaerator the air is easily removed from water and contact area is provided by bubbles in the water, so packing is completely unnecessary and additional cost.

 

[MJCronin]

More information in DA failures and failure mechanisms here:

https://www.steamforum.com/steamforum_tree.asp?master=4926

https://www.eng-tips.com/viewthread.cfm?qid=209396

https://www.powermag.com/deaerator-degradation-managing-remaining-life-and-component-replacement/

http://mmengineering.com/wp-content/uploads/2015/07/Conduit-Vol-15-No-2.pdf

https://www.nationalboard.org/Index.aspx?pageID=180

MJCronin
Sr. Process Engineer

 

[gotothesky]

Thank you all for replies.

I know Packing column is a stripping device rather than a distillation tower....

Make-up water comes into top side of the vent condenser of deaerator.
This make-up water has much quantity of oxygen, and the oxygen in Make-up water should be removed in the vent condenser.
Steam (Oxygen stripping media) comes into bottom side of the vent condenser...
Make-up water and steam contact together at the trays in vent condenser....
The above Operation way is very similar to the packing column as a stripping device.
The conventional vent condenser of deaerator(Tray type deaerator) is also stripping process to remove Oxygen...

The material of packing is various from steel to plastic....
If we use plastic material for packing... we can reduce fabrication cost.
I don't know exactly. but, it can easily keep the required performance with small amount of packing materials for the deaerating process.
And, To install steel trays in deaerator, it seems difficult to make trays' supports.
But, Packing can be filled randomly in a deaerator.... this will make fabrication of deaerator easy....

 

I am no designer but I know the Standard Model is there for a reason.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[gotothesky]

Dear ironic metallurgist

I admit your opinion...
But, My question does not confirm normal practice......

If my proposal is better than the normal, and we get better conclusion, it's better for us.

Regards,

 

[Dhurjati Sen]

Google BHEL. You may come up with something interesting.

They make boilers and accessories among other things. Their de-aerators did have packing, but of course, those were unlike that found in crude distillation columns or elsewhere.

Even in DM plants, degassers have packing (probably Pall rings)

DHURJATI SEN
Kolkata, India

 

[gotothesky]

Thank you, Dhurjati Sen for your kind confirmation..

Regards,