[Gasification] mycoremediation of tarry water

[Mark Ludlow]

Hi Stuart,

The goal in large-scale steam generation (powerplants as
well as warships) is to produce steam above the critical
point-steam with a pressure of 3206 psia (221 bar) and a
corresponding saturation temperature of 705degF (374degC)-a
region where there is no meaning to the words "vapor" or
"liquid". There is only a single phase in this
"supercritical" region. When this steam is expanded through
power turbine nozzles it expands and the pressure is
reduced. The result is very dry superheated steam which
returns to the sub-critical realm and is recycled back to
the steam generator.

 

Your Navy friend was talking about something much different
than any of us are likely to encounter while trying to tap
the energy from a biomass gasifier. The metallurgy itself is
extremely important in these operating regions. 300 psig is
another world altogether yet who of us feels totally at ease
next to one of these boilers? (After 25-years I'm still
squeamish.)

 

Can't all of that high-entropy heat that needs to be "sunk"
from an ORC system be used to dry a fuel source that would
otherwise be completely unusable?

 

Mark

 

From: Gasification
[mailto:gasification-bounces at lists.bioenergylists.org] On
Behalf Of stuart mather
Sent: Friday, February 1, 2013 5:18 PM
To: Discussion of biomass pyrolysis and gasification
Subject: Re: [Gasification] mycoremediation of tarry water

 

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. 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.

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?

Stuart.

 

  _____  

From: Kevin <kchisholm at ca.inter.net
<mailto:kchisholm at ca.inter.net> >
To: Discussion of biomass pyrolysis and gasification
<gasification at lists.bioenergylists.org
<mailto:gasification at lists.bioenergylists.org> > 
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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