[Gasification] Wood Chip classificaton

[Peter & Kerry]

I have read about "solar tunnels" for chip drying in the UK and tried it 
here in Oz with good success. Choose a sloping site, lay out a roll of 
black plastic as the floor, lay your chips in a 2-3" thick layer on this 
(holding the edges up with lengths of 3 x2 works well). Use 3/8" steel 
rod in a hoop shape every 3' or so and cover with clear plastic sheet. 
The hoops only need to just clear the chip so there is a bit of an air 
gap across the top of the layer. You could also use timber cross pieces  
such as from dismantled pallets, or old poly pipe in place of steel 
rods. Leave a narrow flap open at the bottom and top ends of your 
"tunnel", thermal syphoning does the rest.

You can also lay such a tunnel down slope from your chip storage and do 
not add chip directly to this but rather you exit the top of the tunnel 
under the floor of your chip storage via fine grate floor, the hot air 
percolating up will dry a much deeper bed of chips.

Finally for the really dedicated you can add a raised floor at least 2' 
high filled with coarse rock as the base of your chip storage, then 
finish with a fine mesh floor over this for the chip to rest on.  This 
tends to extend the drying time each day as the thermal mass stored in 
the rock from the up-swelling hot air continues to release its heat for 
a few hours overnight, helping prevent cold moist air from being drawn 
back in during this period (so long as you remember to close the bottom 
flap of your tunnel when the Sun sinks low...!).

Cheers,
Peter Davies
Real Power Systems Pty Ltd


On 15/04/2012 5:00 AM, gasification-request at lists.bioenergylists.org wrote:
> Re: Wood Chip classificaton