Some possibly naieve questions a bit outside the box::
I assume we are considering mostly the cleanup of filters and equipment.
Can the chemical energy in these compounds be used in another process?
Is water the only solvent that can be used? (e.g. vegatable oil? .... )
Can the tars be captured is such a way as to become a useful fuel?
(e.g. fiber filters processed to? .... )
Craig
On 2/3/2013 9:50 AM, Kevin wrote:
Dear Stuart
----- Original Message -----
*From:* stuart mather <mailto:[email protected]>
*To:* Kevin C <mailto:[email protected]> ;
[email protected]
<mailto:[email protected]>
*Sent:* Saturday, February 02, 2013 8:17 PM
*Subject:* Re: [Gasification] mycoremediation of tarry water
------------------------------------------------------------------------
*From:* Kevin C <[email protected]
<mailto:[email protected]>>
*To:* stuart mather <[email protected]
<mailto:[email protected]>>; Discussion of biomass
pyrolysis and gasification <[email protected]
<mailto:[email protected]>>
*Sent:* Saturday, 2 February 2013 2:50 PM
*Subject:* Re: [Gasification] mycoremediation of tarry water
Kevin wrote:
....While I have not seen a report showing that blackwater
disposal is harmful to the environment, I have not seen one that
says it is not harmful either. However, a competent Gasifier
Operator sent me pictures of his blackwater dump site a few years
after he stopped dumping blackwater there, and the plants growing
there seemed just as vigorous and healthy as nearby plants outside
teh dump zone.
>
> Best wishes,
>
> Kevin
That's intriguing Kevin,
So I wonder why there seems to be a general consensus that dumping
tarry water in a pond amounts to environmental vandalism. Not
saying your gasifier correspondent was making it up. But you would
think the President of Myanmar would have better things to do than
declare black water gasification leach ponds toxic sites Military
juntas aren't well known for their environmental awareness. So why
the concern about tar ponds people?
Stuart.
# A "Tar Pond" or "Blackwater Disposal Pond" is a highly
concentrated "disposal situation". Too much of anything is almost
certain to be a problem. One cannot grow carrots or wheat in a
pond used to dispose of distilled water, and ethanol alcohol is a
poison when taken in excess quantities at high concentrations, as
an extreme examples. The issues here are one of both toxicity and
concentration. A "Gasifier Tarpond" could indeed become qualified
as a 'superfund site." However, the same chemicals, if spread in
dilute form over say 1, or 10, or 100 square miles may present no
significant hazard, and may even yiled a net benefit.
# I would say intuitively that there is a combination of "toxicity
and concentration" above which, gasifire tar disposal is "bad",
and that there are "toxicity and concentration" combinations below
which gasifier tars are not hazardous, and may even be beneficial.
I don't know all the compounds in gasifier tars, and the
concentrations below which they can be "generally considered as
safe." In my opinion, nobody can responsibly say for certain that
"gasifier tars are toxic" unless one specifies both the components
and concentration. Neither can anyone say for certain
that "gasifier tars are safe" unless one has a rational data base
to support the statement.
# The process of smoking fish, meat, and other food products can
be looked on as a way to dispose of "gasifier tars." :-) The fact
that such "smoke tars" preserve foods proves that such tars are
toxic to some life-forms. Some studies suggest that smoked foods
are bad, while others suggest that while there may be some "cancer
deaths" as a result of eating such smoked foods, the benefits from
reducing deaths from pathogenic organisms that would otherwise be
present greatly exceed the "smoking detriments."
# "The way to eliminate the gasifier tar problem is to eliminate
tar formation in the first place." This is not that difficult with
properly designed and operated gasifiers. This can be done, as is
evidenced by the many gasifiers in operation fueling IC engines,
with no tar problems. Stratified downdraft gasifiers, and updraft
gasifiers are well known as "tarry gas producers." In some
applications, such gasifier systems can be very appropriate,
because of their generally lower capital cost, and their ability
to handle a wider range of fuel sizing and moisture content. Such
gases can often be burned directly, without need for tar removal.
TLUD stoves, which are basically "an updraft gasifier with a
build-in burner to destroy the tars" are an excellent example of a
gasification system where tarry gas is not a problem. If one wants
to pipe such gas to a burner at a distance from the gasifier, then
tar build-up in piping is likely to be a problem. Water quenching
of such gas will remove many of the tars, ash and char that cause
pipes to plug. Then one has the problem and cost of dealing with
the "blackwater." If the problem, and cost of dealing with it are
big enough, then it may be better to employ a different gasifier,
and different fuel preparation techniques, to produce a gas with
an acceptable tar level.
Best wishes,
Kevin
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