[Gasification] Characterization of waste water from biomass gasification equipment: A case-study from Cambodia

linvent at aol.com linvent at aol.com
Sat Jan 16 18:52:23 CST 2016

 Seems complicated.?
Leland T. "Tom" Taylor
Thermogenics Inc.?

-----Original Message-----
From: James Joyce <james at jamesjoyce.com.au>
To: gasification <gasification at lists.bioenergylists.org>
Sent: Sat, Jan 16, 2016 3:31 pm
Subject: Re: [Gasification] Characterization of waste water from biomass gasification equipment: A case-study from Cambodia

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