Re: question: water to steam at great depths

JLeo wrote:
> - I'm looking to solve a dispute between myself and a few others.  A
> 5-6 mile (or more) deep shaft is dug into the Earth's crust to a point
> where the temperature of the surrounding rock is sufficient enough to
> boil water (450 F possibly).  Is it possible to turn a mile high
> column of water to steam in this shaft or would a horizontal shaft
> need to be created (because of head pressure) to be able to turn this
> water into steam?  If possible in the column, do you feel the the
> steam wold condense before exiting shaft?
> - The dispute began over a discussion about volcanic vents in the
> deepest parts of the Atlantic.

Hmm, I don't have the answer but I'll tell you how to determine it. 
There will be steam if the pressure is below the critical pressure of 
water. There will not be steam if the pressure exceeds the critical 
pressure. The critical pressure can be found in text books. You'll want 
to look at the phase diagram of water and specifically of salt water.

To determine the pressure use the density of water ~1 gram/cc. Make a 
column of water with a cross-sectional area of 1 cm^2 then determine the 
weight in kilograms. Then multiply that by 9.8 to determing the pressure 
in Newtons/cm^2. That is your pressure. Convert that number to any other 
units as needed.

Now to answer your other questions. Seems like your asking about 
producing electricity from geo-thermal energy. A good library that has 
physics and engineering texts should have many books that will describe 
different concepts some of which has been implimented. Now for the 
volconic vents look up back issues of Nature, Physics Today, and 
Scientific American. The latter probably being the best for you. Those 
publications as I remember has had articles on the volcanic vents in the 
Oceans.