[Gasification] On the subject of H2 and O (was N2 removal)

[Greg Manning]

Hi Stephen, thanks for the reply.

OK, I somewhat understand you, BUT, wouldn't water be doing a phase
change in the core of a gasifier as well ?

What I was getting at, is if steam is produced in cavitation in cold
water, then wouldn't the shift effect also happen within the core
during phase transition (from water as a liquid, to water as a vapor,
when heated by the core) within the same boundaries of effect as water
to steam in the trailing edge of a propeller ? (all of these
situations involve lower that normal pressure zones).

Aren't contrails produced in water vapor on the wing tips of an
airplane because of this same pressure drop phase shift, causing a
dew-point change?

The core of most gasifiers runs in a dynamic lower than atmospheric
pressure ( a very low internal barometric pressure) (suction based
units), so the same shifts should apply  during phase transition,
shouldn't they ?

I understand that a pressure fed gasifier would behave differently
(and I've personally observed this) than a suction based one, I'm
speaking about suction based gasifiers.

Somewhat lost,
Greg


On Sun, Mar 18, 2012 at 8:26 AM,  <sabbadess at aol.com> wrote:
> Greg,
>
> The energy doesn't change.  The bond energy in the water is constant
> regardless of pressure.
>
> The cavitation issue is different.  It is a phase change phenomenon, not a
> chemical change one.
>
> Stephen
> -----Original Message-----
> From: Greg Manning <a31ford at gmail.com>
> To: Discussion of biomass pyrolysis and gasification
> <gasification at lists.bioenergylists.org>
> Sent: Sun, Mar 18, 2012 9:02 am
> Subject: [Gasification] On the subject of H2 and O (was N2 removal)
>
> Greetings List.
> Since we are speaking input air, I thought I might ask a somewhat
> related question.
> Water gas shift. I know there are many that have talked about this,
> and I understand the basics.
> However, here is the question.
> At what negative pressure ( negative in/wc) does the shift move down
> the temperature scale, to the point of being within the 1000 - 1200 c
> area ?
> We all know that propeller cavitation produces steam in water that is
> 10 c (or there abouts), I have to assume (not being a chemist) that
> the same negative pressure effect would also apply to other principals
> when dealing with water.
> --
>  Regards,
> Greg Manning,
> Brandon, Manitoba, Canada
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-- 
 Regards,

Greg Manning,
Brandon, Manitoba, Canada