What about metal in gasser fuel?

[Gooserider]

A question just came up over in the gear room, and I didn't know if it has been asked over here, and I think it's a significant potential issue...

Probably all of us that process our own firewood have encountered foriegn objects embedded in trees from time to time - most common is probably nails and such, but also I've heard of all sorts of other hardware, some of it larger...

Sometimes it gets found by hitting it with a chainsaw, but a lot of it can be surrounded by wood that has grown over the object, and the only way that it gets found is when you dig it out of the ashes...

It doesn't seem like a big problem for wood stoves, but what about gasification boilers? Would it cause problems with plugging up the slots? If the object falls through, what happens to it in the secondary burn chamber, which seems up in the melting point temperatures, at least near the center of the flames... Does it pose any risk of damage to the ceramics?

Gooserider

 

[jebatty]

Would it cause problems with plugging up the slots? If the object falls through, what happens to it in the secondary burn chamber, which seems up in the melting point temperatures, at least near the center of the flames… Does it pose any risk of damage to the ceramics?

I've had a few nails and small iron/steel articles that were embedded in wood which I have burned. No known problem of any kind. I find the pieces either in the ash at the bottom of the firebox or at the bottom of the gasification refractory tunnel with the little bit of ash that accumulates there. Since I spread the ash on the ground, I pull out any metal, which is quite obvious to spot in the ash.

Iron melts at 2800F, aluminum at 1220F, lead at 620F, and copper at 1980F. It would be pretty unusual to find anything other than iron/steel in wood; maybe lead from a bullet that hit a tree (I found lead about 10" into a large pine log which I was sawing into lumber, the band saw sliced right through the bullet -- I think it dated from the English invasion of North America).

As to melting, It would be interesting to know exactly where in the "flame" of the gasification burn the 1800-2000F gasification temperature occurs. I have a feeling that the extremely high temp is very localized and quickly cools to a lower temp as the combusted gases expand, flow out of the refractory and then flow through the fire tubes. Maybe someone has measured the temp on the surface of either the top or the bottom of the refractory tunnel. In any case, it appears not to be hot enough to melt iron/steel.

 

[Dave T]

I spoke to Zenon about the possibility of steel and nails having an effect on my EKO he said you don't have to worry about the nails doing any damage at all, as long as they are not jammed or lodged in the nozzles..He also said it is a waste of time to pull the nails out,he burns a lot of pallet wood and cleans the nails out of the secondary chamber..Z is using an EKO 40 standard.. Dave

 

[Duetech]

I have found some 1/2" diameter lag bolts around 8" in length and a couple of bolts in the 5/8" diameter in the ash of my EKO40. Some in the upper chamber and some in the lower chamber that were glowing on one end. I have not found any damage from the bolts.

 

[altheating]

The biggest problem is when nails and such are sticking out of the firewood. It may strike the ceramics and errode it away. Nails and such that does not strike the (embeded in the firewood) ceramics simply fall through the nozzels and fuse together in the lower chambers causing no damage.

 

[Gooserider]

Thanks for the comments - If the other thread shows up again I will relay the comments that it seems to be a non-issue...

Gooserider