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heat source for firewood drying kiln

Started by mifirewoodguy, October 23, 2008, 08:28:09 PM

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mifirewoodguy

I'm looking at building a firewood drying kiln that will dry approx 12 face cord of wood per charge over approx 2-3 day. My main concern is the heat source, we have an unlimited supply of scrap wood to burn so my first idea is a wood fired boiler but Im not sure if it can develop enough heat to maintain the 180-220 degrees needed to dry the wood in 2-3 days. Ive looked into big hp boilers but their in the 20,000-30,000 dollar price range, just a tad bit out of my league.. Any suggestions or information would be greatly apprieciated...Lee

zopi

Barrel stove and a high temp fan to keep it moving and exchange part of the air?

It'd kind of suck because you'd have to feed it...

Or a Biomizer. <GRIN>
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beenthere

Welcome to the forum.
Interesting project.
Will those temps you mentioned dry firewood in 2-3 days? What wood would you be drying, and how large would the split pieces be?

south central Wisconsin
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DanG

I'd go with direct heat like the barrel stove Zopi suggested.  Stoke it with pine scraps during the day, then hardwood for a long overnight burn.  The pine will release its heat faster, but you'll have to stoke it more often.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Don_Lewis

Steam is the best way but expensive. We have customers who have built their own wood fired steam boilers but that even is a big deal. You might check to see if one of the wood fired boiler people will okay using a thermal fluid. That is often done in dry kilns. The fluid is heated to 300 degrees or so and pumped like hot water. Otherwise put in a bigger chamber and at 180F, which you can reach woth a big enough wood fired boiler, you can dry in about 5 days. We have several cutomers doing that. We also have some using steam.

mifirewoodguy

Our pieces will be slightly smaller than the norm, about 3"x 14" give or take. We package them .75 cu ft to a pack, shrink wrapped ,labled and a handle on it. Most of the drying will be in wire baskets that will hold approx 1/2 cord at a time. We'll run 24 baskets each charge. This is going to be a trial and error for us. Everything Ive read if you can keep a somewhat constant temp arround 220 degrees you can dry red oak to < 20% moisture in about 3 days. I'm all ears as to input or info if guys have tried this and if its working? We go through approx 5000 cord of wood a yr and we need a fast turn around of dry wood... I havent built the box as of yet because Im waiting to figure out what heat sorce we'll be using ...

mifirewoodguy

We use premium hard woods in our packs, The norm here in Mich are, Red/White/Black Oak. Ash, Elm,Cherry, Black Walnut,Hickory,Maple soft and hard.

DanG

That's a lot bigger operation than I was picturing.  I guess the ol' barrel stove wouldn't quite cut it, eh? :D :D
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Don_Lewis

You are right that you could do this in 3 days if you heat the chamber to 220F (105C) and keep the humidity low and have good air flow. We have customers doing that.

cantcutter

I would consider the following.

1. build a large solar collector that pumps hot water through coils on the wall of the kiln. Down side would be that it would only be operational in the summer months.

2.The wood boiler could store its heat in a bed of rocks underground (or tank of water) and then the kiln could draw heat from that so you did not have to keep it fired all the time. 

3. A bio-mass boiler would be my first choice, but they are exspensive. A system could be home built pretty easy.

I would not mess with steam on an experimental basis. Too dangerous.

zopi

Got Wood?
LT-15G GO chassis added.
WM sharpener and setter
And lots of junk.

mifirewoodguy

Ive been looking at the biggest wood fired boilers they make for commercial use, like the Central boiler Pallet burner.Some claim 1,000,000 btu output, but I'm wondering  what temp that will get me when it reaches the heat exchangers.

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