[Stoves] Burning low quality ethanol

[Paul S. Anderson]

Stovers,]

Harry Stokes and others can correct me on the technical stuff.  This message is
about low quality ethanol.  Hydrous ethanol contains some water.  A major
expense in the production of ethanol for vehicle (IC engine) use is the removal
of the final percentage of water, which I believe is about 5%.  I suspect that
exceptionally low quality alcohol might have up to 20% (or more?) water.

Does anyone have information about production of LOW quality ethanol?

Anil Rajvanshi has a pressurized alcohol stove that he says can use fuels up to
50% water.  Even at 40% or 30% or 20%, that is significant!!  I assume in his
stove that water is evaporated, which does represent a loss of some quality
heat because of the energy to evaporate the water that only comes out at 100
deg C, which is not contributing much to the higher temperatures that are
needed to bring the cookpot contents to boiling.

The gel fuels have about 5% water, and that hinders their output of heat at
cooking temperatures.

In the Lily burner, several months ago I ran a test of ethanol that I
intentionally diluted by higher and higher percentages of water.  I think I
stopped at about the 50% mark.  Interestingly, high water-content ethanol does
still burn in the Lily burner.  Clearly you do not get any extra energy from
the water.  But in the case of the Lily burner, it did not lose/waste much
energy boiling away the water.  If there is only 5% or maybe 10% water content
in the ethanol, it is possible that percentage might be evaporated during
normal use.

In my simple testing, I found that the burner ran out of ethanol and still had
significant weight remaining.  This was most of the water.  Later that can is
heated (using waste heat above 100 deg C) to drive out the accumulated water,
so that the burner can be re-used many many times.

Explanation:  The ethanol vaporizes at 78 deg C and the water stays behind in
the metal can unless temperatures of 100 deg C are reached or exceeded.  I
suspect that this selective vaporization occurs in the "beverage can stoves"
(Pepsi can stove and Zen stove) that are self-pressurizing with only small
holes for the vapors to escape into the air where the flame consumes them.  For
the "open top" containers with liquid alcohol exposed (such as the Trangia
campstove and some fondue burners) I suspect that more water is evaporated, but
I have no testing to support nor refute that opinion.

In the case of the pressurized ethanol burners, the water is still mixed in with
the ethanol when it moves through the tube to where both water and alcohol are
expelled and evaporated.

What does this mean?  Maybe a lot IF there are production quantities and cost
savings making low quality alcohol.  Maybe nothing in other situations.

Comments please.

Paul
-- 
Paul S. Anderson, Ph.D., Geography professor - Emeritus
Telephone:  USA-309-452-7072 (residence and office)
Internet site:  www.ilstu.edu/~psanders
For my gasifier stoves info, go to:
http://bioenergylists.org/contributors#Paul_Anderson





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