Re: GAS-L: Drying beech wood using superheated steam.

[tvoivozhd <tvoivozd@roanoke.infi.net>]

Cornel Ticarat wrote:

> Dear gasifiers,
>
> I'm intending to build a wood dryer using superheated steam. I know this drying method is a good one. The wood I want to dry is beech wood. It is cutted into small pieces of about 20 - 25 cm long and 4 - 10 cm thick. It's moisture content: 45 - 50 % (very fresh cutted wood ! ). I intend one batch of wood for drying to be of 6 cubic meter.
> As far as I know, what is necesary for that is a boiler for generating steam and a drying room. The output steam's temperature have to be of no less than 200 Celsius degrees and it's pressure no less than 4 bar durind all the drying process.
> I read in a Russian old documentation paper that they used this drying method and have had very good results. They dried beams beech wood, having the following dimensions:
> 120 x 200 mm and 4 - 6.5 long. The initial moisture content: 40 %
> After 7 (seven ! ) hours the moisture content decreased to 16 % !!!
> The above mentioned steam parameters I have from that Russian documentation.
> Does anyone have some practical experience with this drying method?
> I would be very grateful to anyone of you who would accept to discuss about this.
>
> Regards,
>
> Cornel (Romania)

Tvoivozhd---superheated steam drying works well.  It is not necessarily the lowest cost method---a consideration important in most countries.  Here is an extensive bibliography of past and present drying methods.  If the quantity of wood to dry is not immense, and your local amount of sunshine permits, consider one or several solar dryers.  A
hard drive committed hara kiri, and deleted the files I had which had instructions and pictures for building various solar dryers.  If you wish, I will  rebuild that file and send it to you.

http://www.innovacorp.ns.ca/infosvcs/lumber.htm

http://www.dekker.com/e/p.pl/0737-3937/016/006/toc  (Too expensive for most individuals, but perhaps a Romanian government library may have this $675 book from McGill University in Canada)

http://www.books.mfi.com/wood/HighTempDrying.html  (a book on the effect of drying at various temperature levels, not academic approach, of kilns in action)

http://www.woodbin.com/prods/wow/wow_specs.htm  (data at your fingertips on 910 tree species and wood products around the world, 300 kb on your hard-drive)

http://www.vacutherm.com/goliath.htm  (rehandling is an economic curse to be assiduously avoided---here is a commercial website solution---drying wood a full lumber truck load at one time).

http://www.tfri.gov.tw/publish/21-3e.htm  (Taiwan study, higher temperature drying significantly more economical of energy than low temperature drying)

http://www.tfri.gov.tw/publish/91-1e.htm  (Taiwan study on pine, similar conclusions)

http://www.forestry.ac.cn/mcs/mcsnew/klsy.htm  (mainland China source of commercial drying system)

http://iridium.nttc.edu/env/doe/e/curry.html  (The Thermodyne process---save energy by recycling water vapor in a dryer instead of exhausting it to atmosphere)

http://www.anu.edu.au/Forestry/wood/drying/kiln.case.html  (Casehardening in drying process, measuring and alleviating stress to produce high-quality lumber)

http://www.njc-usa.com/wooddy/default.htm  (Wood Dryer Systems website, calculating your costs)
http://www.woodweb.com/~industry/machineryfinder/search.html  (Woodweb, search site for components of wood, wood products systems)

http://www.fpl.fs.fed.us/documnts/div982.htm  (Forest Products Research Lab, Madison, Wis.---one of very best worldwide sites for forest products research information)

http://www.woodtechmag.com/db_area/archives/1998/9809/softwood.htm  (more on how critical relieving drying stress is to a manufacturer of wood products)

http://www.durastick.com/contact.htm  (you don't have to tolerate sticker-stain, get rid of it)

http://www.hartingdale.com.au/~adh/Solar_Kilns.html  (and if your climate permits, think about the solar option)





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