Just for the record, and in case anyone is interested in providing a more accurate evaluation to this really interesting subject, I believe the exergetic analysis of the system would give useful hints about eg the tradeoffs between direct contact of wood and exhaust gases x heat transfer only, etc. Cannot remember right now about the literature but if asked I will go back to my dust collecting shelfes in order to dig out a couple of book names and authors. regards, Luiz Magri Rio de Janeiro
--- On Thu, 12/16/10, Bruce Jackson <[email protected]> wrote: From: Bruce Jackson <[email protected]> Subject: Re: [Gasification] engine exhaust relative humidity To: "Discussion of biomass pyrolysis and gasification" <[email protected]> Date: Thursday, December 16, 2010, 12:01 AM Hi, Toby, I suppose your scenario is what would eventually happen. Although I would copy Doug Williams and run a serpentine exhaust arrangement of pipes with the wood laying on the pipes. Keeping the exhaust seperated from the wood. The point I gleaned from your comments was more about what happens when we condense the water out of the exhaust. There is a lot of sensible heat that could be used drive water out of wood especially here. We have a opportunity here to take advantage of the dry air this time of year to subliminate much of the water on the surface of the blocks. I digress. I was more interested in the properties of the engine's exhaust. I suppose with air being almost 80% nitrogen, we could assume that engine exhaust's ability to hold water would be the same? BPJ ________________________________ From: Toby Seiler <[email protected]> To: [email protected] Sent: Wed, December 15, 2010 8:24:44 PM Subject: Re: [Gasification] engine exhaust relative humidity Robert, I thought Bruce was asking how much water is in the engine exhaust after it is running on producer gas. I believe he is wanting to dry wood fuel by directly introducing IC exhaust into a stock of wood fuel... but could be mistaken. For the most part, the producer gas he is beginning with, pre-engine, is perhaps 50% nitrogen, 27% carbon monoxide, 14% hydrogen, 4% carbon dioxide, 3% methane, 2%oxygen (wiki). Maybe he is doing better in hydrogen and reducing N... I don't know. It seems the 50% nitrogen continues and the 27% CO would make CO2, leaving the 14% Hydrogen to become H2O (vapor). Also one must "follow the heat". It takes about 1000 btu to make liquid water at 212f to go to vapor (drying wood must go liquid to vapor). Where is that much heat coming from? In direct introduction I think the wood will have condensate on it, not dry it out. It will raise the temperature, but not make it dry. Of course it is all relative to the amount of wood one is drying. If you gasify 10 lbs and dry one, it hardly seems there is an advantage, although possible. Best regards, Toby Seiler Seilertechco _______________________________________________ The Gasification list has moved to [email protected] - please update your email contacts to reflect the change. Please visit http://info.bioenergylists.org for more news on the list move. Thank you, Gasification Administrator _______________________________________________ The Gasification list has moved to [email protected] - please update your email contacts to reflect the change. Please visit http://info.bioenergylists.org for more news on the list move. Thank you, Gasification Administrator _______________________________________________ The Gasification list has moved to [email protected] - please update your email contacts to reflect the change. Please visit http://info.bioenergylists.org for more news on the list move. Thank you, Gasification Administrator
