Fw: Re: Ethanol & hydrogen production

From: "Joel Moore" <joelmoore@psu.edu>

> >At 8:40 AM -0700 on 8/13/04, David F Siemens wrote:
> >>On Fri, 13 Aug 2004 11:13:26 -0400 Joel Moore <joelmoore@psu.edu>
writes:
> >>> Washington Monthly has an interesting article about 1) an alternative
> >>>
> >>> way to produce ethanol that results in a net gain (rather than the
> >>> current net loss) in energy and 2) a catalytic method to change
> >>> ethanol to hydrogen that requires little energy. The catch with
> >>> using
> >>> hydrogen/ethanol in this way is that the fuel cell technology that's
> >>>
> >>> favored right now doesn't work well. However, another (solid-state)
> >>>
> >>> fuel cell technology does exist that may work with some tinkering.
> >>>
> >>> http://www.washingtonmonthly.com/features/2004/0407.jaffe
> >>>
> >>> Joel
> >>> --
> >>If you report this accurately, (1) indicates the necessary revision of
> >>thermodynamics and the implementation of perpetual motion. As for (2),
> >>the loss of the energy of the carbon in ethanol with the use of only the
> >>hydrogen will be a major loss.
> >>Dave
> >
> >Hi Dave,
> >
> >Don't know if you meant to send the above to the list or not. Sorry
> >for my imprecision. On (1) I meant net gain with respect to fossil
> >fuels (since currently 1.3 gallons of petroleum is required to
> >produce 1 gallon of ethanol). On (2) just reporting what was
> >written. Not clear myself why one wouldn't just burn the ethanol
> >straight away and skip the hydrogen step.

The leading fuel cell technology for automotive applications has been (and
might still be) proton exchange membrane (PEM) fuel cells. They require a
rather pure hydrogen input lest their converter (the fuel cell "stack")
become fouled. Car companies are working on devices that extract hydrogen
from gasoline. To use these same fuel cells with ethanol, similar devices
that extract hydrogen from ethanol are required.

Closing the development gap is the direct alcohol fuel cell (DAFC) which can
run directly on ethanol and is less susceptible to stack fouling. This
technology was hung up on a development problem which has been solved, but
has yet to surpass PEM technology. For details, see www.benwiens.com
For some reason, this important technology was not mentioned in the article.

The "solid-state" fuel cell is probably a reference to the solid-oxide fuel
cell, which is feasible at a scale larger than that needed in automobiles.
And they do run hot.

It makes much more sense to me to opt for an "ethanol economy" than a
"hydrogen economy", especially when fuel storage is taken into account. But
why ethanol should even be converted to hydrogen makes little sense when
DAFCs catch up with PEM FCs.

Dennis Feucht,
www.innovatia.com
Received on Thu Aug 19 13:55:45 2004