[Gasification] Gasification Digest, Vol 6, Issue 17 Where does room moisture go in the winter time?

Ron Wagner ron.wagner at yahoo.com
Wed Dec 13 17:20:57 CST 2006


I just dealt with a minor kitchen flood that ended up
in a corner of the basement. I have also been putting
humid dryer air into my basement, rather than vent it
out. I could not collect any water in my dehumidifier!
Fans quickly dried things out. My house was quickly
dry. Where does the H20 go?

Could I dry biomass in my electric dryer? The humidity
dissapears.The heat goes into the house. Maybe I could
dry it in a burlap bag.

Ron Wagner
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> Today's Topics:
> 
>    1. heat required for drying (Toby Seiler)
>    2. Re: heat required for drying (MMBTUPR at aol.com)
>    3. Re: heat required for drying
>       (Rodenhuis, E.J. (Erik Jan,	Student TBK))
> 
> 
>
----------------------------------------------------------------------
> 
> Message: 1
> Date: Wed, 13 Dec 2006 05:33:22 -0800 (PST)
> From: Toby Seiler <seilertechco at yahoo.com>
> Subject: [Gasification] heat required for drying
> To: gasification at listserv.repp.org
> Message-ID:
> <861580.27485.qm at web38201.mail.mud.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
> 
> Dear Erik, 
>    
>   I'm probably repeating something that you know. 
> It takes just over 1000 btu to turn one pound of
> water (liquid) into vapor (after reaching 212f) and
> in the condensation gives back about 970 btu. Of
> course one pound of water raised one degree is a
> btu., but ambient to 212f is relatively small when
> considering phase change, but not inconsequential. 
> Then come issues like the molecular bound water
> versus free water, when dealing with woody material.
>  Generally, I believe drying must target a 10 to 16%
> moisture content which is about the end of free
> water and beginning of bound water in wood. 
> Calculating the incoming weight of the water content
> in the fuel less the outgoing desired will give the
> weight desired to be removed (as vapor), times the
> 1000 btu/lb (plus ambient to 212f), gives the energy
> required to come out of the process, divided by
> efficiency, for input energy.
>    
>   One would think that some practical use would
> exist for the energy given up and not just discharge
> to the atmosphere as steam.  It takes a lot of
> energy to dry, but the wise was of the energy from
> condensation seems prudent.
>    
>    
>   Regards,  Toby Seiler
>    
>    
> 
>  
> ---------------------------------
> Access over 1 million songs - Yahoo! Music
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> ------------------------------
> 
> Message: 2
> Date: Wed, 13 Dec 2006 08:53:40 EST
> From: MMBTUPR at aol.com
> Subject: Re: [Gasification] heat required for drying
> To: seilertechco at yahoo.com,
> gasification at listserv.repp.org
> Message-ID: <d2c.1da5f66.32b15fe4 at aol.com>
> Content-Type: text/plain; charset="US-ASCII"
> 
>                to   Gasification List      from   
> Lewis L Smith
> 
> Ref the terms "free" versus "molecular bound" water.
> 
> I recall from my biomass days that we measured the
> water content of grasses 
> by heating a sample of the grass until dry in a
> small oven. This gave us an 
> "oven dry" sample which was then weighed. This
> weight was subtracted from that of 
> the original material, and the difference was
> divided by the latter to give 
> an estimate of the percent H20 in the harvested [or
> sun-dried] grass. Such 
> information was of course essential for making
> boiler efficiency calculations and 
> for other purposes.
> 
> I was told by one of the persons performing these
> tests that the oven only 
> extracted the intercellular water, not the
> intracellular water, so the dried 
> sample was really only 94% "dry". I eventually came
> to ignore this distinction in 
> my calculations as everyone else did, and it made no
> difference of importance 
> for our purposes.
> 
> Was our intercellular H2O what you call "free"
> water, and our intracellular 
> what you call "molecular bound" ?
> 
> Cordially. End of message.
> 
>  
> 
>  
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Wed, 13 Dec 2006 15:54:17 +0100
> From: "Rodenhuis, E.J. \(Erik Jan,	Student TBK\)"
> 	<e.j.rodenhuis at student.utwente.nl>
> Subject: Re: [Gasification] heat required for drying
> To: <MMBTUPR at aol.com>, <seilertechco at yahoo.com>,
> 	<gasification at listserv.repp.org>
> Message-ID:
> 
>
<C655E6719422744297B5910BC105AAD15FBEA1 at EX02.service.utwente.nl>
> Content-Type: text/plain;	charset="us-ascii"
> 
> Lewis, Toby and list,
> 
> True, but as you say it doesn't make a difference
> for our purposes. I
> conducted similar tests on samples, simply dry the
> samples in an oven at
> 110 degrees Celsius until they stop losing weight.
> There is no free
> water anymore in the cellular space, but there is
> still bound water in
> the cell walls. 
> Given the ambient temperature and air humidity we
> can calculate the EMC
> (equilibrium moisture content). There is a
> calculator available at
> http://www.woodbin.com/ref/wood/emc.htm  
> 
> Toby, thanks. I knew this, when formulating it this
> way you have the
> theoretical energy need for drying. As you mention
> correctly the next
> step is attributing an efficiency to the drying
> system used. Same
> question formulated another way.
> 
> Erik
> 
> 
> -----Oorspronkelijk bericht-----
> Van: gasification-bounces at listserv.repp.org
> [mailto:gasification-bounces at listserv.repp.org]
> Namens MMBTUPR at aol.com
> Verzonden: woensdag 13 december 2006 14:54
> Aan: seilertechco at yahoo.com;
> gasification at listserv.repp.org
> Onderwerp: Re: [Gasification] heat required for
> drying
> 
>                to   Gasification List      from   
> Lewis L Smith
> 
> Ref the terms "free" versus "molecular bound" water.
> 
> I recall from my biomass days that we measured the
> water content of
> grasses 
> by heating a sample of the grass until dry in a
> small oven. This gave us
> an 
> "oven dry" sample which was then weighed. This
> weight was subtracted
> from that of 
> the original material, and the difference was
> divided by the latter to
> give 
> an estimate of the percent H20 in the harvested [or
> sun-dried] grass.
> Such 
> information was of course essential for making
> boiler efficiency
> 
=== message truncated ===




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