Vacuum Decarbonator Design

[ChemEng87]

Hello guys,

My manager asked me to provide him with a preliminary design (for now) and a detailed design (later) for
a vacuum decarbonator to reduce the total alkalinity of source water. I went through so many industrial and academic references but I couldn't find any material with detailed information about vacuum decarbonator/degassifier containing design equations and rules of thumb. There are so many information about regular degassifiers but not "Vacuum Decarbonator/Degassifier".

I would appreciate if you guys could give me some links to references or text books which has design manuals for vacuum decarbonator.

Thanks,
Nojan

 

[StoneCold]

Let me start off by saying I have no idea what a "vacuum decarbonator/Degassifier" is.
However if I wanted to decrease the alkalinity of water I would use ion exchange resins. If I only cared about the calcium content, I would use a typical water softener. If I truly wanted to eliminate some of the ions I would use separate positive and negative ion beds and regenerate them with acid or caustic appropriately.
Could it be that a vacuum Decarbonator/Degassifier is a very old technology?

Anyway Goodluck

StoneCold

 

[ChemEng87]

Dear StoneCold,

Thanks for your response. That's what I have found as well, using Ion Exchange Resins for reducing alkalinity. However the problem is, that's what our customer asked us to do, to design a vacuum decarbonator to reduce alkalinity via removing CO2 from source water. I am not exactly sure about the terminology, whether it is "vacuum deaerator/degassifier/decarbonator". Whatever it is, I need to design a column which works under vacuum (since no steam is available) and removes CO2 from source water.

Thanks

 

[Compositepro]

Try using "vacuum stripper for carbon dioxide" or similar as a search term.

 

[ChemEng87]

Dear Compositepro,

Thank you for your response. I did what you said and what I found was mostly articles investigating CO2 vacuum strippers qualitatively. I was wondering if there is any step-by-step design instruction out there. In other words, the equations describing the column's diameter, height, type and size of packings, etc.

Thanks

 

[bimr]

You can look in a book;

http://www.sciencedirect.com/science/article/pii/S0042207X00004127

or call one of the major water treatment companies like H & T;

http://www.hungerfordterry.com/vacuum_summary.htm

The water treatment company can probably give you a rough size in a few minutes. It would probably be easier if you called the water treatment company as that is the place where you will purchase one or get a guarantee.

 

[bimr]

Here are some design parameters if you want to size the unit:

http://www.lantecp.com/wp-content/uploads/2013/04/LanpacBrochure.pdf

 

[ChemEng87]

Dear Bimr,

The first link you provided is one of the few resources I found already which gives a bit of information about column height, but not other parameters. Your suggestion about calling companies, that's what I am doing currently but I would prefer to come up with a design by myself due to some business issues. And the third link, as Lantec is a packing provider, most of the parameters in that link is related to packings.

For now, I need an estimation of column height, height of different sections of column (HTU, Spray. Demister, Sump, etc.), column diameter, vacuum pump design criteria, and anything related to a vacuum degasser which needs to be considered in the preliminary design so that you can come up with the estimated overall pricing for this unit. If I could have a reference that could provide step-by-step design criteria, that would be awesome.

Thanks

 

[bimr]

If it was possible to procure design manuals for equipment, then the sellers of the equipment would be put out of business. You have enough to come up with a preliminary design. If you want a detail design, then you need to procure the equipment.

 

[ChemEng87]

Dear Bimr,

Let me disagree with you. For instance there are lots of Heat Exchanger manufacturers out there, while you can find more than sufficient material on step-by-step heat exchanger design. That doesn't throw them out of the business, does it? Well, heat exchanger application in industry is so common in industry that makes it outstanding, so lots of material on it, but vacuum degasser? Not that much, that's the point! That's why I asked you decent guys to help me find references.

Thanks

 

[bimr]

The packing is the key component in the degasifier. Knowing the process design values of the packing, you can determine the preliminary diameter and height of the unit. The operating pressure is determined by the concentration of oxygen that you are trying to obtain.

http://www.eng-tips.com/viewthread.cfm?qid=155466

A vendor should be able to provide you with a +/- 20% estimate within a few hours if you provide the required capacity.

Yes, heat exchangers are relatively simple pieces of equipment items and made by numerous vendors, in your words common.

A vacuum degasifier is a custom engineered equipment package. The Vendor will consider the detailed equipment design to be proprietary information. The term proprietary information is often used interchangeably with the term trade secret.

The mantras of proprietary information:
•Businesses make money
•Information is a business resource
•Information is proprietary
•Proprietary information is secret
•Secret means "not readily available"