How to Remove the Ethanol in Active Carbon

Leave it in the oven longer.

Leave it in the vacuum chamber longer.

Set it on fire.

thank you, i need to run this as mass production. the time 4h is the longest. may be the cacuum chamber is a good suggestion.

Maybe you need a different type of activated carbon?

http://homedistiller.org/activated_book1.pdf

You can do it fast with backflushing steam through the carbon bed. This is a common used process in the industry to recover solvents and alcohols. Separation of the condensed steam (water) is done with a density filter. You will have to build in a safety level (in your separation column) because ethanol mixes partially with water.

Is there some forced air movement during ovening or you just wait for the temperature to do the job? S.M.

there is forced air flow.

I am not sure of the reason you are trying to remove the ethanol from the activated carbon. Activated carbon is relatively cheap compared to trying to regenerate it. So replacement with new carbon is easy and cheap. If you want to extend the life of the carbon for filtration purposes, one method is to inject hydrogen peroxide prior to the filter. The peroxide will catalytically activate the carbon and in effect give more adsorption sites. The effective filtration runs can be extended by a factor of ten. It works quite well on all types of carbon. If it is spent carbon that must be cleaned prior to disposal, you may want to just consider time as a form of treatment. All you will need to do is store it under covers and perhaps again you can inject peroxide into the pile. With time biological processes will destroy the ethanol and other organic contaminants attached to the carbon. Bacteria are very adaptable but the reason to add peroxide is to prevent other decomposing contaminants from forming alcohol.

I have not tried to regenerate AC for many years. It was impossible to meet criteria laid out and we simply resorted to using virgin activated carbon. If I am off base with your targets, ignore my post.

in my process i need to use ethanol. but in the last FG parts, the customer has request for ethanol content.

Try spray drying it. All measures must be taken to prevent flashing of the solvent and to condense it. The material is put into a vortex like chamber at the top and swirls down at a adjustable rate and with an adjustable heat. The dried powder is collected at the bottom into containers. For some applications an rotary valve must be used to prevent vapors from exiting through the powder collection section.

This is how many dry adhesives, foods such as lemonade, etc. are made. This method is normally used to separates the solid in solutions but there is no apparent reason why it couldn't be used for your processing goal.

http://www.youtube.com/watch?v=u2LhmpDUjKk

http://en.wikipedia.org/wiki/Spray_drying

http://www.niro.com/niro/cmsdoc.nsf/WebDoc/ndkk5hmc6zSprayDryersSprayDryers

Good Luck, Old Salt

i use spray drying to reduce from 50% weight to 300NG/G.

Just curious. Why is it necessary to get down to 20ng/g?

it's customer request

You need to create conditions of lower pressure and higher temperature to cause the ethanol to evaporate into the surrounding air, and more time to let it happen to get down to the required level.

Juggle these in combination with things available to you.

Or just mix it with some fresh carbon to average out the density/concentration.

thank you, i have found a microwave dry machine to run DOE. thank you!