Originally By Tony Ackland
Reusing Carbon after Polishing Spirits
You can reuse your carbon by washing it, and heating it up so that it will release any of the trapped fusels. Les explains ...
The bottom line is you could heat the carbon at top setting on your fan assisted oven for a year and still be in no danger. Wouldn't like to see the bill for the electricity though :)
As far as steam is concerned [from a domestic steam-cleaner] I do not think that would work. The alcohol molecules need to be vapourised from the fissures of the carbon. Water molecules (steam) would not do any more good than actually boiling the carbon in a pan of water as they would not necessarily displace the alcohol from the fissures.
GRANULATED CARBON ACTIVATION
Most Carbon is activated using steam. Activation is also accomplished using chemicals. Wood based carbons steam activation involves a two step process, carbonization and activation. Carbonization occurs in an oxygen deficient environment at high temperatures, 700 degree Celsius. Activation of carbon occurs by using steam where temperature of the carbon is raised to 1800 degrees.
Reactivating carbon is a simple process where the spent carbon is thermally reactivated . Reactivation occurs a temperatures between 1400-1700°F where ether volatile organics or oxidized off forming CO2 and water. The non volatile organic compounds are carbonized to form char. In the final phase of the process steam is used to reactivate the carbon. Approximately 80-90% by dry weight of the carbon is recovered in this process. The remainder is made up with virgin carbon. Reactivated carbon performs exactly the same in adsorptive capabilities as virgin carbon.
Information courtesy of www.onionenterprises.com
I get my carbon in a plastic filter from work. I cut the filter open with and dump the dirty carbon into a 40litre container and fill it with hot water in my shower. I let it settle and decant the dirty water. I repeat this until the water is clear, usually 4 times. I then boil it up in a pressure cooker to really clean it and sterilise it. I then drain it off rinse again and put it in a pyrex lasagne type container. I microwave it on full for 5 mins at a time stirring it after each 5 mins. After about 20 mins it is dry but keep a close eye on it. I then microwave it for 40 seconds at a time stirring each time. it looks dry but after a while it starts to gives off dry vapours again.
It gets extremely hot so a pyrex dish is essential. it is important to stir to prevent hot spots. Once i didnt stir for a while and when i did stir it was glowing red in the middle! after about 10 blasts at 40 seconds the vapors stop coming off and i then stop and let it cool overnight. the vapours have a choking smell and are a bit like smoke since they are "dry" but they dont stink the room or anything.
How much ? I didnt weigh it but it looks 500g judging from the 1 kilo bags i used to get. The microwave is 800W, but microwaves do vary in efficiency. Mine seems to heat small cups of water faster than my last 800W maybe it has hot spots or something. I would go very slowly your first time maybe 2 mins at a time until appears totally dry. When it is dry it just falls off the spoon like sand. if you cant leave it in the microwave to cool down (incase "she" finds it) be very careful where you leave it. I took it out once and put it on some newspaper and the paper started to smoke! it works very well when recharged, but i always put lots in each gallon jar anyway.
It's slightly different when the carbon is wet. Water is generally considered to be a good conductor, but that is only because it can readily dissolve salts that disassociate in solution into electrically charged ions, and these carry the current. Water that has been through the distilling process has no salt content, and any salts present in the carbon/water mix will generally be those lingering on after the manufacturing process. The water separating the carbon granules is therefore a fairly good insulator and sparking will also be experienced, usually with generation of a bit of hydrogen and oxygen as the water is broken down by electrolysis. The heat generated will initially go towards heating and vaporizing the water, so keeping the carbon below its ignition point. However, when all that water has boiled off, the dry carbon will then heat up - as before - and ignite. One "interesting" side effect you might notice if treating damp carbon in a microwave is that you can end up with an explosion, for that dampness may well contain a goodly proportion of alcohol if you haven't first washed the carbon thoroughly. The atmosphere in the microwave can quickly reached critical proportions with the oxygen in the air, and a spark is a tried and true way of igniting that mix! You can even get the same effect in an ordinary oven from a red-hot heating element if the carbon still has a lot of alcohol left in it ... ending up with a muffled thump and the oven door blowing open!! (Been there, done that, and would be wearing the T-shirt if it hadn't been scorched!)
Moral? Do NOT dry carbon in a microwave oven as the risks of fire or even explosion are too great, and wash carbon thoroughly in lots of clean water before drying in an ordinary oven ... keeping the oven door slightly open to vent any flammable gases that will almost certainly be given off, as no amount of ordinary sluicing in water will get rid of all the alcohols deep inside the carbon granules. Proof that they are indeed still there will become more than evident to your nose as they are vaporized ... so keep the kitchen windows wide open if you don't want the whole house to reek of congeners!