A little politically incorrect, to be sure, but it makes engineering
sense. The final steam condensation cycle of the nuclear-driven steam
turbine, electricity producing power plant is mostly waste heat,
usually exhausted to the atmosphere by those huge hourglass shaped
towers you see. Ethanol boils at about 79 degrees Centigrade, with the
steam condensing back to water near 100 deg. C, a heat transfer system
could be designed to cook the sourmash in an integrated system, saving
the cost and carbon emissions that would come from a hydrocarbon fueled
distillation column. Both would keep our energy dollars out of the
hands of Arab terrorists.-Jitney

I agree. Apparently it takes higher heat to cook the mash, but for finall
distillation this could be high enough. They could also just use the corn
stalks as fuel, gasified or not. CO2 neutral is better than using NG.

yahoo.com> wrote in message news:1164320235.696134.164870@l39g2000cwd.googlegroups.com...

In alt.energy.renewable jtnospam@yahoo.com wrote:

However, the exhaust temperature may or may not be higher than the
ethanol demands, certainly heating up the temperature of the cold side
of the power plant drops efficiency.

OTOH - nuclear process heat, where lots is needed, can be very handy, as
you avoid the lossy conversion to electricity, and in some cases can use
nearly 100%% of the energy.
One place this can make lots of sense is nuclear-hydrogen, where the
heat from the reactor is used to produce hydrogen.

If only hydrogen was a bit easier to store.

On 24 Nov 2006 Ian Stirling mauve.demon.co.uk> wrote:

It would be within a few degrees, so it would take a
minimal amount of current to run electric heating bands
putting the needed heat exactly where it is needed on the
still for best recovery of ethanol.
A still runs best with certain zones at precisely
different temperatures, and this would be an ideal
way to do it with almost no other source of heat.

"Ian Stirling" mauve.demon.co.uk> wrote in message news:4566dabf$0$8722$ed2619ec@ptn-nntp-reader02.plus.net...

You could take the CO2 from the ethanol production and the H2 and make SNG.
California imports 80%% of the NG it uses. If we have a CO2 neutral source and ...

Isn't the waste heat the same from nuclear as from
coal plants, they all must use final cooling water. (snip)

Yes, that is true, and I say, bring it on. It would be a lot easier to
do in the planning stage than a retrofit. But the waste heat from coal
or gas driven steam would work just as well.-Jitney

At 10,000 psi, the tank volume and total fuel
load (tank and fuel) is not too much different than
gasoline because of the 60,000 BTU per pound of
hydrogen vs the 20,000 BTU per pound of gasoline.
But if natural gas and propane have not become
popular after being available for at least 40 years or
more, how can hydrogen have any hope.

I think the key to efficient use of hydrogen would be rapid use after
production, obviating the need for large capacity storage. Gas for
residential and business heat will accept up to a 4%% mix without
modifying the burners, and though that doesn't sound like a lot, it is
huge. I agree with the other poster that hydrogen cars are a carmaker
PR stunt, storage and distribution are just not cost effective.
Moreover, about 85%% of hydrogen production is from natural gas(still by
far the most economical), which defeats the whole point about renewable
sourcing. -Jitney

I have been suggesting using waste heat to run
stills for a couple of years, at least, and would like to
see some efforts to implement it on a large scale. (snip from Joe
Fisher)

A well thought out post. I started the thread both because I thought
it could work but also to provoke continued thought on the use of waste
heat from power plants. I think that under the right circumstances, the
waste heat could be used for industrial process heat. For smaller,
perhaps NG fired power plants, the waste heat could be utilized for
district heating of apartments.-Jitney

On 30 Nov 2006 05:29:43 -0800, jtnospam@yahoo.com wrote:

Which is why all new power plants should be
smaller and located where the waste heat can be used.

But if large fuel cell stack prices come down enough,
new small communities might make their own power,
I wonder how much waste heat there is from certain
fuel cells.