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<div> <font class="Apple-style-span" color="#000000" face="arial"><span class="Apple-style-span" style="font-size: small;">Seems complicated. </span></font></div>
<div style="font-family:arial;color:black;font-size:10pt;clear:both;"><font class="Apple-style-span" face="arial">Sincerely,</font><br>
<div><font class="Apple-style-span" face="'Comic Sans MS', sans-serif">Leland T. "Tom" Taylor</font></div>
<div><font class="Apple-style-span" face="Arial, Helvetica, sans-serif">Thermogenics Inc. </font></div>
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-----Original Message-----<br>
From: James Joyce <james@jamesjoyce.com.au><br>
To: gasification <gasification@lists.bioenergylists.org><br>
Sent: Sat, Jan 16, 2016 3:31 pm<br>
Subject: Re: [Gasification] Characterization of waste water from biomass gasification equipment: A case-study from Cambodia<br>
<br>
<br>
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<pre style="font-size: 9pt;"><tt>Hi Tom, I might make a few comments and caution people not to discard the char <br>
filtering option based on a couple of negative experiences. It may not so much <br>
be the case that char filtering does not work ... just that it does not work the <br>
way it has been tried. <br>
<br>
- Not all biochars are the same and neither are all activated carbons. Most <br>
activated carbons are highly microporous, which is not very useful for liquid <br>
phase adsorption. If you did not use one known to be highly mesoporous (like a <br>
wood char rather than nut char) then it is worth revisiting. <br>
<br>
- Dry chars tend to be hydrophobic. That makes them useless for liquid phase <br>
adsorption until they have had a chance to condition and be able to "wet" <br>
through into the pores. If the pores are full of air that needs to be displaced <br>
before you can adsorb anything else. In my experience mixing time, elevated <br>
temperature and perhaps acidity? can facilitate the wetting process. Packed bed <br>
filters don't allow for much in the way of mixing time. <br>
<br>
- Particle size will play an important role, as it interacts with the surface <br>
tension of suspended matter. If a packed bed filter did not work then I would <br>
try mixing fine char with the water in a mixing tank (possibly at elevated <br>
temperature) before filtering that mixture through a packed bed char filter. <br>
<br>
- Aged tarry water may well be a different beast to fresh tarry water. <br>
<br>
<br>
One other idea: <br>
In coal processing interface change agents such as diesel and MIBC are commonly <br>
used to alter the surface interaction between fine coal and air bubbles for the <br>
purposes of floating out the diesel and fine coal. See <a target="_blank" href="https://en.wikipedia.org/wiki/Froth_flotation">https://en.wikipedia.org/wiki/Froth_flotation</a> <br>
. A similar process might work for the hydrophobic fraction of the tarry water. <br>
The remaining soluble and hydrophilic fractions are probably more <br>
biodegradeable. <br>
<br>
Froth flotation is also used in sugar refineries and is very effective at <br>
removing very finely dispersed colloidal matter from solutions of soluble <br>
matter. <br>
<br>
In either process the key is to introduce fine solids that the colloidal matter <br>
and air bubbles can attach to. <br>
<br>
<br>
Regards, <br>
<br>
James <br>
<br>
------------------------------ <br>
<br>
Date: Sat, 16 Jan 2016 11:41:12 -0500 <br>
From: <a href="mailto:linvent@aol.com">linvent@aol.com</a> <br>
To: <a href="mailto:gasification@lists.bioenergylists.org">gasification@lists.bioenergylists.org</a>, <a href="mailto:spaco@baldwin-telecom.net">spaco@baldwin-telecom.net</a> <br>
Cc: <a href="mailto:gasifiers@bioenergylists.org">gasifiers@bioenergylists.org</a>, <a href="mailto:biochar@yahoogroups.com">biochar@yahoogroups.com</a> <br>
Subject: Re: [Gasification] Characterization of waste water from <br>
biomass gasification equipment: A case-study from Cambodia <br>
Message-ID: <<a href="mailto:8D31E93D7DA4606-1F38-3863F9@webmail-vm013.sysops.aol.com">8D31E93D7DA4606-1F38-3863F9@webmail-vm013.sysops.aol.com</a>> <br>
Content-Type: text/plain; charset="us-ascii" <br>
<br>
I have tried commercial activated charcoal and it doesn't work. It is far <br>
superior to bio char in adsorptivity, and the tarry water passes through it <br>
without removal.? <br>
Sincerely, <br>
Leland T. "Tom" Taylor <br>
Thermogenics Inc.? <br>
<br>
<br>
<br>
<br>
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