12 replies to this topic

[Pressure Vessel Design]

Hello, 

 

I am currently designing an activated carbon column to purify CO2 gas and remove VOC and ethanol. I have done some research concerning the adsorption of CO2 onto activated carbon however, I am still unsure of how the process works. I am aware that to recover the CO2 once it has been adsorbed is by desorbing however won't some of the VOC be recovered with the CO2? 

I apologise for my lack of understanding I have very limited understanding on the adsorption process. 

[Art Montemayor]

What, exactly, is your gas feed mixture composed of and WHAT are you removing (adsorbing)?

[Pressure Vessel Design]

Hello Art Montemaryor, 

 

Thank you very much for your reply I apologise for my lack of information

 

My gas feed mixture consists of:

 

99% CO2

0.6% ethanol

0.1% ethyl acetate

0.2% 3-methyl-1-butanol

0.1% 2-methyl-1-butanol

0.02% phenylethyl alcohol

0.04% ethyl octanoate 

 

At a flowrate of 135240.66 kg/day. This gas mixture was formed during the fermentation of molasses with s.cerevisiae to produce ethanol.

 

My purpose is to purify the CO2 to >99.9% by removing the ethanol and the VOC's (ethyl actetate, 3-methyl-1-butanol..etc). From research I found that CO2 is adsorbed when using activated carbon but that it can be regenerated to recover the CO2. I've found that quite a lot of industries are using activated carbon to remove VOC's formed in the fermentation process and purify the CO2. I apologise for my lack of understanding I haven't yet found a clear explanation of how the process works.

[breizh]

Hi ,
First step should be a water scrubber to eliminate the alcohol before using AC .
My 2 cents
Breizh

[Pressure Vessel Design]

Hi Briezh,

 

My original design was to use a water scrubber to eliminate the alcohol however after conducting sample calculations a design couldn't be developed, after speaking to my supervisor I noticed that my values do not meet the design criteria for a water scrubber. Instead I condensed off the alcohol and separated it using a flash drum with the advise from my supervisor.

This stream containing 99% CO2 1% VOC's would then enter the AC.

[breizh]

Hi ,
It's what I saw in the ethanol plants (3 ) I visited last year . At that time I was investigating a way to recover CO2 from fermentation .

Probably for greater purity you need a second step , why not adsorption using AC?

Good luck

Breizh

[Pressure Vessel Design]

Hi Briezh,

 

Thank you very much for for your quick reply. Yes that's exactly what I am investigating at the moment, adsorption using AC. I understand the adsorption concept but I am unsure of the adsorption process using AC to purify CO2 and eliminate VOC. I found that CO2 is adsorbed onto the AC and to recover the CO2 a second step is necessary known as regeneration. I am just very unsure with how the process happens and I apologise for my lack of understanding. 

[breizh]

Hi ,

Another resource about CO2 purification is attached  .

 

http://www.union.dk/...dustrial-gases/

 

Good luck . 

Breizh

Edited by breizh, 06 April 2015 - 08:18 PM.

[Pressure Vessel Design]

Hi Breizh,

 

Thank you very much for your help. I am still trying to figure out the process of purifying CO2 with AC, I think it may have to do with the pore size and particle size of the components to attach themselves to the AC. But, I am still trying to figure out the kinetics and process.

 

Thank you again

[breizh]

Pressure Vessel design ,

late information .

Good luck

Breizh

[Napo]

Dear Breizh,

 

I can´t download the last attatched: "Adsorption Manual US Army.pdf"

 

Can you help me?, or it is the same attached in this post.

 

Many Thanks.

 

Regards,

 

Napo.

Attached Files

•  Adsorption Design Guide (US Army CE).pdf   734.79KB   34 downloads

[breizh]

yes it is .

Breizh

[Pressure Vessel Design]

Thank you very much Breizh the documents helped a lot, I have come to understand how to design it for a multicomponent gaseous stream