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 <[email protected]> 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 <[email protected]> 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: [email protected] >>> [mailto:[email protected]] On Behalf Of >>> [email protected] >>> Sent: Sunday, March 18, 2012 7:55 AM >>> To: [email protected] >>> 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 <[email protected]> >>> To: Discussion of biomass pyrolysis and gasification >>> <[email protected]> >>> 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, <[email protected]> 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 <[email protected]> >>>> To: Discussion of biomass pyrolysis and gasification >>>> <[email protected]> >>>> 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 >>>> _______________________________________________ >>>> Gasification mailing list >>>> to Send a Message to the list, use the email address >>>> [email protected] >>>> to UNSUBSCRIBE or Change your List Settings use the web page >>>> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org >>>> for more Gasifiers, News and Information see our web site: >>>> http://gasifiers.bioenergylists.org/ >>>> >>>> >>>> _______________________________________________ >>>> Gasification mailing list >>>> >>>> to Send a Message to the list, use the email address >>>> [email protected] >>>> >>>> to UNSUBSCRIBE or Change your List Settings use the web page >>>> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org >>>> >>>> for more Gasifiers, News and Information see our web site: >>>> http://gasifiers.bioenergylists.org/ >>>> >>> >>> >>> >>> -- >>> Regards, >>> >>> Greg Manning, >>> Brandon, Manitoba, Canada >>> >>> _______________________________________________ >>> Gasification mailing list >>> >>> to Send a Message to the list, use the email address >>> [email protected] >>> >>> to UNSUBSCRIBE or Change your List Settings use the web page >>> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org >>> >>> for more Gasifiers, News and Information see our web site: >>> http://gasifiers.bioenergylists.org/ >>> _______________________________________________ >>> Gasification mailing list >>> >>> to Send a Message to the list, use the email address >>> [email protected] >>> >>> to UNSUBSCRIBE or Change your List Settings use the web page >>> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org >>> >>> for more Gasifiers, News and Information see our web site: >>> http://gasifiers.bioenergylists.org/ >> >> >> >> _______________________________________________ >> Gasification mailing list >> >> to Send a Message to the list, use the email address >> [email protected] >> >> to UNSUBSCRIBE or Change your List Settings use the web page >> http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org >> >> for more Gasifiers, News and Information see our web site: >> http://gasifiers.bioenergylists.org/ > > > > -- > Regards, > > Greg Manning, > Brandon, Manitoba, Canada > > _______________________________________________ > Gasification mailing list > > to Send a Message to the list, use the email address > [email protected] > > to UNSUBSCRIBE or Change your List Settings use the web page > http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org > > for more Gasifiers, News and Information see our web site: > http://gasifiers.bioenergylists.org/ _______________________________________________ Gasification mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/gasification_lists.bioenergylists.org for more Gasifiers, News and Information see our web site: http://gasifiers.bioenergylists.org/
