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

Sat Jan 16 12:55:57 CST 2016

Rice husk char has been used to filter gasifier effluent. Tests show about a
20% adsorption of contaminants of interest compared with activated carbon at
80%. It might be a useful in a cleaning process. 

The proliferation of gasifiers in South Asia has occurred mostly since about
2005. I last saw the energy in char used to incinerate scrubber water in a
100 kWe gasifier developed by Energy and Environmental Research Center (EERC
at University of North Dakota) for grass seed screenings in 2006. I know
that Ankur and others have tried this. 

Rice husk gasifiers seem to have either a collection pond  or a series of
cooling and settling tanks with recirculation (with or without  filter). For
the ponds there have been constructed wetlands with water hyacinths and
marigolds. For the tanks it would seem to make sense to continuously
withdraw effluent for biological treatment. Since posting the Cambodia
abstract I have seen research from India, China, and Germany in which
various organisms have been used to break down gasifier effluent. The most
promising seems to be a bioreactor which grows vegetables. 

The systems of interest would be the village scale (20-65 kWe), rural
enterprise (rice mill) scale (100-200 kWe) or larger. 

Rice husk is the most abundant raw material. The products should be biochar,
water that is clean enough to reuse, and food, feed, or fiber. 

Tom

From: Gasification [mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of linvent at aol.com
Sent: Saturday, January 16, 2016 8:41 AM
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

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. 

Sincerely,

Leland T. "Tom" Taylor

Thermogenics Inc. 

-----Original Message-----
From: Paul Anderson <psanders at ilstu.edu <mailto:psanders at ilstu.edu> >
To: Discussion of biomass pyrolysis and gasification
<gasification at lists.bioenergylists.org
<mailto:gasification at lists.bioenergylists.org> >; spaco
<spaco at baldwin-telecom.net <mailto:spaco at baldwin-telecom.net> >
Cc: gasifiers <gasifiers at bioenergylists.org
<mailto:gasifiers at bioenergylists.org> >; biochar <biochar at yahoogroups.com
<mailto:biochar at yahoogroups.com> >
Sent: Sat, Jan 16, 2016 5:20 am
Subject: Re: [Gasification] Characterization of waste water from biomass
gasification equipment: A case-study from Cambodia

Dear Gasification Listserv and Biochar Listserv,

The excellent comment by James Joyce (below) did not reach the Gasification
readers.   It only went to the Biochar readers.   Interesting for two
reasons (overly simplified, but to make a point):

1.  Gasification for power (engines) is what causes the problem of
contaminated waste water, but those readers did not see the "solution
offered".  THEY are the people who could test and evaluate the solution.

2.  Biochar production (for agriculture and carbon sequestration) has been
proposed to make a filter-char that is to be burned, which is what biochar
production is trying not to do.   That is, char as filter for wastes made by
trying to burn all of the biomass to ash.

Those of us who are subscribed to both lists will see the full discussion.
Let's hope that this is a functional solution.

(Of course it is better if the nasty contents in the waste water were not
created in the process of making the electro-mechanical power.)

To James Joyce, I say "Thanks."

Paul Anderson

James Joyce wrote:

Seems to me that the smallest foot print treatment would be to filter the
water through char, gravity dewater and then dry the char to less than 30%
moisture, then combust it at over 1000 deg C in a chamber that maintains a 2
second residence time for the gases released from the combustion. That will
yield useful heat while destroying the recalcitrant hydrocarbons. In
locations with weather that does not make solar or even bed drying viable,
the process will generate more than enough heat to run a heated air drier.

 After the past mess if dealt with, such a process would probably only need
to be run for a day a week to treat scrubber water from storage tanks (i.e.
never put out to lagoons or open storage where it is of great risk to the
environment).

 The equipment required to do that is far less complicated than the
gasifiers themselves.

Regards,  

James                              Posted by: James Joyce
<mailto:james at jamesjoyce.com.au> <james at jamesjoyce.com.au> 

Doc  /  Dr TLUD  /  Prof. Paul S. Anderson, PhD Email:  psanders at ilstu.edu
<mailto:psanders at ilstu.edu>  Skype:   paultlud    Phone: +1-309-452-7072
Website:  www.drtlud.com <http://www.drtlud.com> 

On 1/7/2016 10:45 AM, linvent at aol.com <mailto:linvent at aol.com>  wrote:

Tom, 

          Thanks for the compliment and appreciation. There were hundreds of
"pot" trials using a wide variety of treatments, extractions, etc. before
the key process was accidentally stumbled on. Other processes have evolved
and include the ability to take sea-water to potable with a fraction of the
cost of distillation or RO. 

          Assumptions about the tar properties including specific gravity
can be quite misleading. 

          One aspect of how to deal with the produced water from a gasifier
is to give it the right type of compound definition and once that is
reached, it makes it much easier to treat it. 

Sincerely,

Leland T. "Tom" Taylor

Thermogenics Inc. 

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