[Stoves] Burning low quality ethanol

[Crispin Pemberton-Pigott]

Dear Paul

This lead back to the question Philip and I was discussing about the amount
of heat available from burning ethanol.  I am preparing another go at the
calculation.

>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.  

When I got to this part I assumed you were selectively boiling off the
ethanol. Do you remember when we talked about the meths drinkers and
concluded that they were boiling off most of the methanol and drinking the
ethanol remaining?

In industry the target for 1 pass through a distillation is 5% water or
less. Given the close condensation temperatures, that is pretty good and
that is what is sold normally. If you have more water than that, someone
started out at 5% and diluted it to sell water at $1000 a cubic metre.

The ethanol gasifiers (which you seem to have) overcome this although you
still pay a lot for the water.

What is the latent heat of evaporation of ethanol? And its specific heat?

It is pretty easy to see that the ethanol would boil off first, cooling the
water as it does so, maintaining the perfect conditions to take out the
ethanol and leave the H2O behind.

One problem I see is that in some countries you are not allowed to heat the
fuel in the tank above the evaporation point at any time because it is a
safety hazard. You can pressurize it, but not heat it because you can easily
depressurize it but not cool it quickly should it fall over.

Come to think of it, that would prevent the Lily stove reaching some
markets.

Huh.

Regards
Crispin