[Gasification] water gas and IC Engine exhaust gas temperatures
Ken Boak
kenboak at stirlingservice.freeserve.co.uk
Tue Nov 21 02:55:52 CST 2006
Jeff and List,
I partially dispute that the charcoal is a catalyst. If it were a true
catalyst, then it would not be consumed. Perhaps just agree that it is both
catalyst and fuel.
Let's not foget the other reaction that's occurring where CO2 recombines
with the carbon to produce the CO.
If a charcoal gasifier is typically 70% efficient, then 30% of the fuel
energy in the charcoal is consumed in the exothermic reactions to provide
heat to drive the endothermic reactions.
There will be a similar efficiency number that can be applied to the blue
water gas reaction.
There is a fair amount of water vapour present in diesel exhaust. My
experiments with the exhaust gas heat exchanger, on a 6hp engine, show that
there are several litres of water contained in the exhaust gases per hour of
running.
However, the exhaust gases seldom reach 400 C, so this would probably
dictate the useful temperature at which they could be fed into the gasifier.
A superheater coil would be need to be placed in the exothermic zone to
supply the additional heat requirement. But due to the exceess air present
in the diesel exhaust it may be sufficient to provide oxygen for the
combustion, or partial combustion of the charcoal, enriching the gas stream
with CO.
This does not yet address the problem that vehicle exhaust is still
approaching 80% nitrogen.
I still think there might be value in the idea of drawing air through the
reactor on the induction stroke, to put it more into the exothermic state,
and then blowing the exhaust gases through it returning it to the
endothermic state.
You would then end up with two gas streams, one containing mostly the
products of combustion (oxidation), and the other containing the reduction
gases.
You would need to separate these gas streams, to ensure that the higher
calorific reduction gases made their way to the engine, and the combustion
gases were recirculated for further reduction.
I am sure that this could be syncrhonised with the engine running at 150
induction strokes per minute
Ken
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