Blue Flames

[Northern NH Mike]

I've got a nice one going tonight. It is five below and I have a great draft. I'm on the downside of a load of maple and noticing beautiful blue flames, pretty much like you would see on a natural gas burner. Is this gas in the wood? I'm not all that schooled on the chemistry of woodburning.

 

[spirilis]

I've got a nice one going tonight. It is five below and I have a great draft. I'm on the downside of a load of maple and noticing beautiful blue flames, pretty much like you would see on a natural gas burner. Is this gas in the wood? I'm not all that schooled on the chemistry of woodburning.

I think wispy blue flames are common when wood is burned down to the charcoal stage... the other week a buddy of mine had a charcoal grill going for steaks and I noticed the flames coming off the charcoal were a mix of yellow and blue. I often notice bluish flames coming off my wood when it's burned down to the charcoal stage. Probably the high temp of combustion, since it's almost pure carbon at that point. I've heard burning anthracite coal, which is also mostly all carbon, produces the same kind of flames.
Any flames coming off the wood, I think, are volatiles (smoke) being driven out and burned when they combine with oxygen. Those are just lower in quantity (since most of the volatiles have been burned out by the time the wood's turned to charcoal) but burn reliably thanks to the high heat of the charcoal + ample available oxygen, and since they burn very hot, they turn blue. If this is bad science or incorrect I apologize

 

[lexybird]

blue flames = very hot fire
last year i had some really good seasoned ash and when i ran my air wide open it over a bed of hot coals it would have a steady stream of blue flames dancing off the splits just like natural gas
really cool to watch through the window

 

[Corey]

bright yellow-white, candle color flame = glowing carbon in the flame (air:fuel ratio is slightly rich, could use more air)
translucent blue flame = fully oxidized flame, all carbon converted to CO2
orange yellow tips, especially on a blue flame = sodium spectral emission
faint purple tips, especially on blue flame = potassium emission
green flame = copper emission (much more rare in the fireplace)

rich blue flames over coals = CO + O2 > CO2

 

[DanCorcoran]

Solids don't burn, gases do. When wood (or coal, or horse poop) burns, it gets hot enough to emit/turn to gas, which is what burns.

 

[albertj03]

I think the OP is referring to jets of blue flames shooting out of the holes in the secondary tubes. It's been really cold here as well (-5 this morning) and I've had some spectacular and longer then normal blues flames jetting out of the holes too.

 

[Northern NH Mike]

I think the OP is referring to jets of blue flames shooting out of the holes in the secondary tubes. It's been really cold here as well (-5 this morning) and I've had some spectacular and longer then normal blues flames jetting out of the holes too.

No, it's a noncat.

These were rich blue coming off the coals.

 

[DanCorcoran]

Regardless of where the flame originates, it is a gas burning (rapidly oxidizing), not a solid. (Not that it makes a hill-of-beans difference..it just explains why flame often seems to originate above the material which is "burning").

 

[firefighterjake]

All I know is that I like the pretty colors . . . especially the blue!

 

[Slow1]

bright yellow-white, candle color flame = glowing carbon in the flame (air:fuel ratio is slightly rich, could use more air)
translucent blue flame = fully oxidized flame, all carbon converted to CO2
orange yellow tips, especially on a blue flame = sodium spectral emission
faint purple tips, especially on blue flame = potassium emission
green flame = copper emission (much more rare in the fireplace)

rich blue flames over coals = CO + O2 > CO2

Thanks! I may just have to print this and keep it near the stove

I've noticed the pretty "rich blue flames over coals" when I'm burning them down with lots of air. I will have to assume then that this is a good sign of very complete combustion then eh? Sure does toss some heat out and glow nice and bright.

 

[ControlFreak]

This is reason I can't handle a gas or pellet stove. The fires are BORING! The gas fire is interesting for the first 20 minutes. The fire from a pellet stove is just plain UGLY. A wood fire is continuously changing and always a pleasure to watch.

I had a gas insert in one of our fireplaces for a while. I got rid of it and picked up another wood insert.

Off Topic: If Obama has his way, the only form of heat we may be able to afford is wood cut from the back.

 

[Northern NH Mike]

This is reason I can't handle a gas or pellet stove. The fires are BORING! The gas fire is interesting for the first 20 minutes. The fire from a pellet stove is just plain UGLY. A wood fire is continuously changing and always a pleasure to watch.

I had a gas insert in one of our fireplaces for a while. I got rid of it and picked up another wood insert.

Off Topic: If Obama has his way, the only form of heat we may be able to afford is wood cut from the back.

Yeah, the wood fire is pretty mesmerizing, almost meditative.

I don't have enough wood to cut in my property, but my wood comes from local dealers/cutters. I'd rather have my heating dollars staying within the local community rather than some nameless/faceless oil company exec in the US or abroad.