Dear Stuart
Quoting stuart mather <[email protected]>:
Kevin
Years ago, while I was in the Navy, during a tour of the engine
room of a warship, one of the turbine boiler engineers warned us
that if we encountered even a tiny high pressure/temp leak
somewhere in the steam plumbing, we wouldn't see it, but it would
instantly slice cleanly through whatever body part got in the way..
I'd forgotten about how dangerous steam can be. Clearly not an
option for small scale set ups, although a small steam engine with
a professionally designed boiler with multiple fail safe features
probably warrants further consideration. But you obviously wouldn't
be building one yourself.
# "Backyard Builders" have built and successfully AND safely
operated gasifiers and engines.
Whereas once the tar issue is addressed in an
environmentally responsible way, the opportunities to lose life and
limb would seem less with a gasifier/ICE approach to using biomass,
and is a tinkerers dream.
# Yes, indeed!
One further question, If the tars stay in biochar from low temp BM
pyrolysis, and the soil bacteria/myccorhizal fungi deal with them,
(are even beneficial I thought), why is the tarry water from a
gasifier scrubber such an environmental hazard?
# Tars in biochar are different from the tars in producer gas, and
additionally, their concentration in soil is probably very much less
than the concentration that would be seen at a "blackwater dump
site." While "blackwater tars" are bad for direct contact or
consumption by people, they may not do significant environmental
harm if disposed in a reasonably dispersed manner. 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
Stuart.
________________________________
From: Kevin <[email protected]>
To: Discussion of biomass pyrolysis and gasification
<[email protected]>
Sent: Saturday, 2 February 2013 6:22 AM
Subject: Re: [Gasification] mycoremediation of tarry water
Dear Tom
Certainly, what you say could be true for 2 MW and larger
facilities that have the technical and economic economies of scale.
Smaller gasifier and engine systems can deliver 1 HP for a
heat rate of about 16,000 BTU/hp-hr. If powering a generator, this is a heat
rate of about 24,000 BTU/kw-hr. I would doubt that small scale steam or ORC
plants could meet this heat rate.
Small gasification plants can be operated safely with a
conscientious Operator, having very basic training. Steam power
plants of any
significant size and pressure, usually Stationary Engineers as
Operators. With
smaller steam Plants, the Operating labour Cost can be very
significant.
Best wishes,
Kevin.
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