[Gasification] Active charcoal
Bruno M.
brunom1 at telenet.be
Mon Feb 20 22:06:20 CST 2012
Hi Anand,
i think you made a bunch of good ( & cheap) suggestions to Darius,
Calcium Chloride is probably one of the cheapest ( cheaper and easier to
get the K2CO3),
since it is common used as a deicing salt on roads ( up to -20°C) and also
in household humidity absorbers ( & odor eliminator) like eg:
http://www.damprid.com/faq# )
but its very hygroscopic, need to be stored dry and in closed containers,
so i guess you can't soak your biomass in a 25% solution and then hoping
it to dry in the sun
( in an humid climate ), but 5% may do fine.
http://en.wikipedia.org/wiki/Calcium_chloride
Safety: Calcium chloride can get very hot when mixed ( concentrated) in
water, and the dust is an irritant.
But there are many sources of material to make charcoal from and
even so many ways to active those carbons.
My guess is too, that for good activated carbon you need to start from
good char,
that means char made at higher temperatures ( higher temp then normally
needed for bio-char )
800-900 °C. & you like to have low ash content.
Maybe Darius this may also be of interest to you:
www.vcharkarn.com/uploads/78/79040.pdf
http://revroum.getion.ro/wp-content/uploads/2010/RRCh_6_2010/Art%2002.pdf
Ones you've done the activation step on your AC,
you will not know HOW active your char is, compared to
commercial AC, & that also depends on your purpose for this AC,
so you'll need some testing of the AC.
Here an example of a big lab specific known for his AC testing service,
with price indication, just you know which kind of test could be done on it.
http://pacslabs.com/activatedcarbon/actesting.php
An example of analyzing different AC made from bagasse:
www.waset.org/journals/waset/v34/v34-36.pdf
A rather simple but much used test, is the 'iodine number' or 'iodine
capacity number',
if you do this on a before and after the activation sample you get a
good impression
of how much more active area has become available.
I guess this can be done on a small budget, and without complex apparatus.
Here is the ASTM Designation: D4607-94
www.czsochem.com.cn/download/ASTM%20Iodine%20test.doc
you may need more tests.
When we know more of the purpose of your AC, and the scale
of your operation we may be able to give more precise advice & tips, i
guess.
Grts
Bruno M.
( chemist)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Op 21-2-2012 1:58, Anand Karve schreef:
> Dear Kevin,
> this work was done by a graduate student as a project. At that time he
> used our charring equipment, but did not tell us the name of the
> chemical or its concentration. It was only later that the Student's
> guide told me about calcium chloride, when I met him at a
> conference. Apparently, one can also use potassium carbonate. The dry
> sugarcane leaves were dipped into 5% solution, removed and dried in
> the sun. The charcoal was tested in their laboratory to verify if it
> was active or not. I don't think anybody actually makes activated
> carbon on a commercial scale by this method. That is why I told Darius
> that he should conduct his own experiments and test it.
> Yours
> A.D.Karve
-----------------------------------------------------------------------------------------------------------------------
> On Tue, Feb 21, 2012 at 1:14 AM, Kevin <kchisholm at ca.inter.net
> <mailto:kchisholm at ca.inter.net>> wrote:
>
> Dear AD
> Very interesting!!
> Is the charcoal that is activated by CaCl2 "good for everything
> that activated charcoal is good for", or is it perhaps equally
> good for some tasks, but not necessarily as good for all?
> What applications have you used the CaCl2 activated charcoal in?
> What % by weight CaCl2, would you use?
> Thanks!
> Kevin
>
> ----- Original Message -----
> *From:* Anand Karve <mailto:adkarve at gmail.com>
> *Subject:* Re: [Gasification] Active charcoal
>
> Dear Darius,
> Normally one needs relatively high temperature to make
> active charcoal, but the pretreatment with calcium
> chloride allows us to make active charcoal even at relatively
> low temperatures. We make charcoal from light biomass like
> agricultural waste and use a TLUD type kiln. You would have to
> conduct experiments using your biomass and your process of
> charring to see if this pretreatment works in your case or not.
> Yours
> A.D.Karve
>
-------------------------------------------------------------------------
>
> On Sat, Feb 18, 2012 at 11:01 PM, Darius
> <darius_tamizi at hotmail.com <mailto:darius_tamizi at hotmail.com>>
> wrote:
>
> Dear Dr. A.D. Karve
>
> Charring material are rubber wood.
> Could you tell me the detail process?
>
> Regards,
> Darius
> ----------------------------------------------------------------
> On 2/18/2012 9:56 PM, Anand Karve wrote:
>> Dear Darius,
>> what material are you charring? We make our charcoal from
>> leaves of sugarcane, which are discarded during the
>> process of sugarcane harvest. By soaking the leaves in 5%
>> solution of calcium chloride, dying them and then
>> converting them into char in a TLUD kiln gives us active
>> charcoal. We have not tested this process in the case of
>> woody material. Perhaps you can do this experiment.
>> Yours
>> A.D.Karve
>> On Sat, Feb 18, 2012 at 10:14 PM, Darius
>> <darius_tamizi at hotmail.com
>> <mailto:darius_tamizi at hotmail.com>> wrote:
>>
>> Dear all,
>>
>> Is somebody there can help me to convert our char
>> into active charcoal?
>>
>> Regards,
>> Darius
>>
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