[Gasification] Vacuum drying (was: RE: Drying)

[Kevin Chisholm]

Dear All

Wood Mizer makes a vacuum lumber drying kiln. Basically, boards are stacked 
in a vacuum chamber, and a vacuum is drawn.

As the wood dries, it cools. The heat of evaporation must be replaced, for 
the process to continue. 1 BTU/pound of water removed. 1 calorie per gram of 
water removed. Wood Miser replaces the heat lost through evaporation by 
inserting layers of electrical resistance tape between the boards.

This system works very well indeed. One problem is the high cost of 
electricity. Another cost is labor to stack the wood neatly. And then 
unstack it carefully after it is dry, so as to not tear the resistance 
strips.

We designed and built a 6,000 square foot solar collector to preheat air 
going to a new kiln holding 32,000 FBM hardwood boards. Worked great.

Best wishes,

Kevin



----- Original Message ----- 
From: "doug.williams" <Doug.Williams at orcon.net.nz>
To: "Rodenhuis, E.J. (Erik Jan,Student TBK)" 
<e.j.rodenhuis at student.utwente.nl>; "Adam Carr, Renergy" 
<adam.carr at renergy.org.uk>; <gasification at listserv.repp.org>
Sent: Thursday, December 14, 2006 10:36 PM
Subject: Re: [Gasification] Vacuum drying (was: RE: Drying)


> Erik,
>
> You ask;
>
>> The article mainly discusses drying of sludge, how effective and
>> efficient would it be for woody biomass?
>
> Vacuum drying of timber, is a commercially developed technology, and I had 
> a
> series of meetings with a developer here in New Zealand, about back in
> 1996-7. I have no further info to offer, but sure that  I  have seen
> referances to vacuum  timber drying in various publications.
>
> Regards,
> Doug Williams.
>
>
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