Sorry guys, My post did not separate the Q+A, so here is a corrected repeat.
Hi Bruce and Toby,
I an sitting here pecking away at other work, so can offer further comment:
Toby, I suppose your scenario is what would eventually happen. Although I
would
copy Doug Williams and run a serpentine exhaust arrangement of pipes with
the
wood laying on the pipes.
My current fuel dryer has all the tubes flowing in parallel so the heat
distribution is fairly even. Inlet temperature is 250C, outlet 50C. The hot
engine air is blown through underneath and through the wood at 50C.
Keeping the exhaust separated from the wood.
I also use the exhaust directly into a 44 gallon drum dryer for wet wood,
and you can dry it faster than you consume the wood for a small system, say
upto 15 kWe in our experience. You can see between 400- 700C as an exit
exhaust gas temperature.
The point
I gleaned from your comments was more about what happens when we condense
the
water out of the exhaust. There is a lot of sensible heat that could be
used
drive water out of wood especially here. We have a opportunity here to take
advantage of the dry air this time of year to subliminate much of the water
on
the surface of the blocks. I digress.
Water certainly can be seen forming on the upper blocks until the fuel mass
heats through. We start with the lid on, then open it up to let the steam
out, and stop when blue smoke begins to show out the top. This is I might
add, using wood blocks for fuel. I found the best way to dry chips was an
old tumble clothes dryer.
I was more interested in the properties of the engine's exhaust. I suppose
with
air being almost 80% nitrogen, we could assume that engine exhaust's
ability to
hold water would be the same?
I cannot answer that directly, but you always have a lot of water in engine
exhaust gas, no matter what fuel, and will show you some in my next Fluidyne
Archive Post.
Hope this is of interest.
Doug Williams,
Fluidyne Gasification.
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