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

Sun Mar 18 22:36:12 CDT 2012

in complete agreement with you on that.

Greg

On Sun, Mar 18, 2012 at 9:59 PM, Thomas Reed <tombreed2010 at gmail.com> wrote:
> Greg blown gasifiers typically operate at a few inches of positive pressure (0.01 ATM) and suction gasifiers at a few inches negative, so both are essentially at atmospheric pressure unless the pressure is purposely increased or decreased .
>
> Tom Reed
>
> Thomas B Reed
>
>
> On Mar 18, 2012, at 3:26 PM, Greg Manning <a31ford at gmail.com> wrote:
>
>> KELBURN,
>>
>> THANK YOU !
>>
>> This is the EXACT thing I needed to see.... proves my point, EXACTLY.
>>
>> I am now of the firm beleif that we CAN (And DO) water gas shift in
>> suction type gasifiers, where as, blown (pressureized) gasifiers can
>> NOT do W/G shift.
>>
>> I think the W/G shift is at a great amount, BUT, it sure proves my
>> caclulations, almost dead on.
>>
>> Thank you Thank you Thank you Thank you
>>
>> Greg
>>
>>
>>
>> On Sun, Mar 18, 2012 at 12:14 PM, Kelburn Koontz <kelburn_k at yahoo.com> wrote:
>>> Making Ice with Vacuum
>>> http://www.youtube.com/watch?v=pOYgdQp4euc
>>>
>>> Check out the ideal gas law.
>>>
>>> Thanks,
>>> Kel
>>>
>>>
>>> On Sun, 2012-03-18 at 08:10 -0700, Mark Ludlow wrote:
>>>> “The steam produced in cavitation is like putting water in a bell jar
>>>> and pulling a vacuum.  If there is enough vacuum the water will boil,
>>>> converting it's temperature into energy for the phase change.
>>>> Eventually you end up with a chunk of ice in the bell jar.”
>>>>
>>>>
>>>>
>>>> Not so! Not enough latent heat is lost. Sensible heat must be removed
>>>> also. In outer space, where there are huge radiative heat losses this
>>>> applies. If folks could make ice with simple vacuum pumps, who would
>>>> mess with refrigeration? It takes energy to evaporate water, not just
>>>> vacuum.
>>>>
>>>>
>>>>
>>>> Plus, when a gas is adsorbed onto a sieve, energy is released. It
>>>> takes the same energy (and then some) to regenerate the sieves. No
>>>> free lunch; no where.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> From: gasification-bounces at lists.bioenergylists.org
>>>> [mailto:gasification-bounces at lists.bioenergylists.org] On Behalf Of
>>>> sabbadess at aol.com
>>>> Sent: Sunday, March 18, 2012 7:55 AM
>>>> To: gasification at lists.bioenergylists.org
>>>> Subject: Re: [Gasification] On the subject of H2 and O (was N2
>>>> removal)
>>>>
>>>>
>>>>
>>>> Hi Greg,
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Sure.  Let's to a simple example so my feeble mind can follow it.
>>>> When I drop cold chips in my gasifier there is some moisture content
>>>> in the chips...this is liquid water in the wood cells.  As the chips
>>>> burn down into the hearth they get hot and the water changes to steam.
>>>> This phase change absorbs some amount of energy.  Then as the steam
>>>> goes through the char, some of it does the water gas shift if there is
>>>> enough heat.  This absorbs even more energy.  The remaining steam ends
>>>> up as condensate in the cooler.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> The steam produced in cavitation is like putting water in a bell jar
>>>> and pulling a vacuum.  If there is enough vacuum the water will boil,
>>>> converting it's temperature into energy for the phase change.
>>>> Eventually you end up with a chunk of ice in the bell jar.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> The water gas shift will not happen in the phase change because there
>>>> isn't sufficient activation energy availble to make the reaction go.
>>>> If it did work that way, there would be hydrogen bubbles coming off
>>>> boat propellers.  That would make a COOL rooster tail!
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Gasifiers do not run a low enough pressure to vaporize the water, like
>>>> the bell jar.  I can get the numbers if you want, but you need to be
>>>> in -13psi range.  That's way more than we pull.
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Any clearer or still muddy??
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> 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 10:09 am
>>>> Subject: Re: [Gasification] On the subject of H2 and O (was N2
>>>> removal)
>>>>
>>>> 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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>>>>>
>>>>>
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>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>>  Regards,
>>>>
>>>> Greg Manning,
>>>> Brandon, Manitoba, Canada
>>>>
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>>>
>>>
>>>
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>>
>>
>>
>> --
>>  Regards,
>>
>> Greg Manning,
>> Brandon, Manitoba, Canada
>>
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-- 
 Regards,

Greg Manning,
Brandon, Manitoba, Canada