Thank you all! It was wery helpfull. Seems you all se roughly the same resaults.
Bob, l dont have fancy gadgets like you (higrometer ) but l usualy burned 4 years old oak chunks, bone dry, but now since l learned oak is bad for condensing hoppers, l will burn mostly alder/wilow/hazelnut chunks, sundryed in summer.
Allso, l am insulateing the hopper with 2" of laminated rockwool/alu foil wich shuld, from my previous experiances with insulated hoppers, make the hopper temperatures in the wood pirolise range, 300-350c. So, if l top the hopper up at a cooldown, the accumulated heat shuld be plenty to boil the moisture of the wood to near 0%. At cooldowns, the hopper is essentialy a charcoal kiln.
Now, there is just the problem of disposeing all the water. At my previous system the steam had to go trugh the hearth and in the cooling pipes. There was about half a liter of condensation collected after l left a hopper full at cooldowns. With water came some tar that culd not be cracked by the already too cool hearth. Needless to say, this was problematic.
It is dispointing that you can not get some kind of hopper cooling tubes in your hopper system to work in the trunk area. It would solve the problems of the moisture going all though the hearth and tars with it. On the positive side the tars you are cracking are making more gases for the amount of wood you are using.
Using the hopper as a kiln to cook the wood is a good idea.
Yes fancy gadgets, you really don’t need them. I usually just put the wood up to my lips, and come pretty close to telling if it is wet or dry enough to go into the gasifier. I haven’t used it for quite awhile just to show everyone on DOW that it is dry wood in the center.
Bob
Yes. “love your wood.” face contact for moisture works with experience/practice. WWII operator reading says they use blow trough for moisture testing too.
Experience with my predominate Doug Fir soft wood and I can tell by chunk weight.
Ha! My trained hand gets really fouled up picking up hickory or mahogany woods.
tree-farmer Steve unruh
Exactly Steve, my moisture meter is in the hand too (weight) over the years of working with wood such things get to you naturaly. Allso the “ring” or “echo” of the wood tells its story.
Its called “filtration aid agent”. Its basicly perlite flour. Wery light and insulative. If touched with a flame, it glows white without phisicaly changeing.
I have dumped a few thousant bags in the dispensing machine in my time here, only now realised this has potential in gasifier related stuff.
At filling the new hearth with fresh charcoal, l usualy make a ash cone first out of some ash from the stove.
Do you think its worth to try and make it out of this perlite flour? Or will it just blow away, since it doesent get sintred as ash does?
I decided to give this a try first, those are ss sacrificial plates, extending all the way to the restriction. The idea is for them to reflect heat, support the ashcone and enable a smooth flow in the hearth. If that doesent work, l think l will try the perlite flour sprayed multiple times with sodium silicate solution (thanks Dave).
Hi Kristijan, my mild steel plates warped down by the reduction zone. Is there any way you could weld stainless steel pipe in between the pieces at the bottom, and have the pipe go to the out side of the reduction pipe? It wouldn’t even have to be stainless steel pipe.That would keep them in place. With the ash packed in behind the plates that should work.
Bob
Kristijan,
A couple more suggestions
I would screw in or cut off the bolts/nozzles flush with the nuts + copper paste on the threads.
The sacrificial plates I would leave the way they are. If any warping occurs in the lower region just bend them in to hide in the ash cone or cut the lower halves off. The ash cone will protect the lower half of the firetube anyway.
Or… similar to Bob’s suggestion: A larger diameter pipe around the restriction could be a lose fit. Only high enough to keep those fingers from warping into the flow path.
Hi guys,
Been buissy last few days, pig slaughter day and anual technical inspection on the Mercedes, meaning l had do dissademble and reasemble everything wg related. Glad thats past.
@TomC, since l hadthe scale out from slaughter day, l weighted the gasifier&hopper. Thats 60 pounds so l think JO and l culd smugle it trugh airport inspection
Here is a pic of my sooty hand next to the hearth.
) but l usualy burned 4 years old oak chunks, bone dry, but now since l learned oak is bad for condensing hoppers, l will burn mostly alder/wilow/hazelnut chunks, sundryed in summer.
