At what Temp does secondary burn occur??????
- Thread starter Hiram Maxim
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
- Status
I've observed this with an inside stove temp of 900-1000 F with my thermometer. Could be off a bit though. Some of the sites mention 1100 F.
http://www.heartheat.com/flameworksOLD/index_WoodComb.htm
As for stovetop temp, depends on your stove.
http://www.heartheat.com/flameworksOLD/index_WoodComb.htm
As for stovetop temp, depends on your stove.
1100f is the number most often cited as the ignition temperature of wood exhaust gases in non-catalytic woodstoves. Catalytic combustor-equipped stoves light off at much lower temperatures, usually around 550f -650f, although I've seen aftermarket woodstove cat elements that claim a lightoff temperaure as low as 350f.
FOR ENGLANDER STOVES
The secondary burn in the Englander Stoves does start at Stove Temperature of 400-450 degrees when using a magetic stove surface thermometer or flue temperature of 700-900 degrees or more if your are using DVL Pipe and a probe thermometer. This information comes from Corie P. whom I did talk to at length today. He did say that he has went up to 1400 degrees on occasion but does not reccommend this temp every day as damage can occur in the stove.
Personally I think he meant around 1100-1200 degrees a few times a day for a period of 15 minutes to burn off creosote ...He did not say ths, but my intuition says he wanted too say this.
The secondary burn in the Englander Stoves does start at Stove Temperature of 400-450 degrees when using a magetic stove surface thermometer or flue temperature of 700-900 degrees or more if your are using DVL Pipe and a probe thermometer. This information comes from Corie P. whom I did talk to at length today. He did say that he has went up to 1400 degrees on occasion but does not reccommend this temp every day as damage can occur in the stove.
Personally I think he meant around 1100-1200 degrees a few times a day for a period of 15 minutes to burn off creosote ...He did not say ths, but my intuition says he wanted too say this.
Guess I was unclear: I was referencing temperatures inside the stove, where the secondary combustion occurs, not stove surface or flue gas temperatures.
Nobody in this house is going to be running any wood stove at 1100-1200 degrees stove top temp. Warped steel and busted welds are ugly. 
So the air that is being heated and is coming out of the tubes (to mix with the smoke) is around 400* to 600*?
also why are there 4 tubes in the stove and not 1 big tube?
Also how far should the tubes be from the top of the stove? My buddy is retro-fitting his 5.0 CF home made stove and he is asking questions
also why are there 4 tubes in the stove and not 1 big tube?
Also how far should the tubes be from the top of the stove? My buddy is retro-fitting his 5.0 CF home made stove and he is asking questions
Hiram Maxim said:
Corie the engineer will have to give us the real reason but my money is on turbulence. For complete combustion you need fuel, air, heat and turbulence. Each of the four tubes in the 30 have the holes angled down at different angles and I bet that that creates said turbulence.
Some stoves like the PEs and Napoleons have the air coming sideways out of holes in the baffles. I wish the 30 could optionally do that because I believe it creates a better secondary burn with a north/south wood load. I don't wish it enough to buy one of those lesser stoves though. :lol:
Hiram Maxim said:
It provides better air distribution - one big tube will not get fresh air all the way to the front of the firebox. Also tubes at the back of the firebox light off and project that heat/flame toward the tubes closer to the front - providing additional heat for them.
Hiram Maxim said:
If you are talking about secondary tube reburners, it would be ~1100F, If you are talking about the base of a cat, it would be 350F for some aftermarket ones and 500-600F on "regular" cats.
Jeez Guys, I waited on the phone for 20-30 minutes to speak with Corie and some 2nd day employee answered the phone and could not answer my questions...so I asked if Corie P. was there....He came on calm and gracious as the virgin mary and answered my questions.. I do only reveal what he did say to me....He also said the new lab experiment is meant to replace the 12 series stove....Please do not shoot the messanger...
Joey Chang
Joey Chang
CFD modeling actually proves this to be untrue. Less ports of larger size offer better mixing and combustion zone penetration than lots of smaller ports.
I think it's just that most manufacturers don't go through the expense to CFD model a firebox and it's easier to get the holes and distribution by using a shotgun approach with lots of little holes. If you use a few larger ports you do have to be choosier on the port location, but you do get better performance and better mixing.
So are you saying that on the Englander stove the surface temp is 400-450 and the firebox temp is 100-1100 deg. when the secondary starts to burn from the tubes??? Am I supposed to close down the primary air and let the secondary do the work for better efficiency or am I messed up about this?
johnnywarm said:
As I recall mine kicked in at about 350* ( stove top ) I'll let you know soon when I start to burn again
It is gonna be different for every stove guys. Smaller fireboxes get up to temp before the stove body does faster than bigger stoves. My 30-NC has to be up around 500-550 while the little Jotul F3 is kicking secondary by 350-400.
The little baby F100 seems like it is blowing secondary flames by the time the kindling is done. The firebox on it is the size of a shoebox.
The little baby F100 seems like it is blowing secondary flames by the time the kindling is done. The firebox on it is the size of a shoebox.
johnnywarm said:
Can`t speak spefically to your appliance, but my insert usually see the secondaries at about 400-475 as measured on the top of the insert. And I emphasize, the top, not on the door front-mounted.
Rule of thumb is that interior temp is 2 x surface temp. An approximation.
Secondary burn as understood by most I think is the visible, sometimes rolling, hanging, or flickering flame at the top of the firebox and around or below the top firebox air inlets. This can occur over quite a broad temperature range, and is related to the amount of combustible gases given off, oxygen available, and a source pilot flame (surface combustion flame on the wood piece). Typically it will occur with a source flame at around 500-600F and as low as about 350F, and continue up to about 1100F. The "secondary" flame occurs away from the wood surface because there in insufficient mixing of the combustible wood gas with oxygen near the wood surface to sustain combustion, and this additional mixing to permit combustion is occurring around the top air inlets in the stove.
Obviously, without the additional oxygen the otherwise combustible gases would simply go up the chimney and efficiency would decline considerably.
Starting at around 1100F and up entirely different processes start taking place. I don't believe it would be normal in a wood stove for these processes to exist to any great extent due to the very high heat, except possibly at the very low end. Gasification boilers operate in the 1100F and up range, with the combustion taking place in specially designed ceramic chambers that can withstand heat up to 2000F and more.
The combustion "flame" at this high end is not visible, and therefore cannot be said to be secondary combustion as usually understood. Carbon monoxide is igniting invisibly at about 1350F, hydrogen at about 1200F, about the same for acetic acid, methane at about 1100-1600F.
In a gasification boiler, the invisible combustion of these products is evidenced simply by a roaring sound - totally invisible. It also may be mixed with some visible, orange to blue, flame, with the flame being representative of other, lower temperature gases also being combusted.
Secondary burn as understood by most I think is the visible, sometimes rolling, hanging, or flickering flame at the top of the firebox and around or below the top firebox air inlets. This can occur over quite a broad temperature range, and is related to the amount of combustible gases given off, oxygen available, and a source pilot flame (surface combustion flame on the wood piece). Typically it will occur with a source flame at around 500-600F and as low as about 350F, and continue up to about 1100F. The "secondary" flame occurs away from the wood surface because there in insufficient mixing of the combustible wood gas with oxygen near the wood surface to sustain combustion, and this additional mixing to permit combustion is occurring around the top air inlets in the stove.
Obviously, without the additional oxygen the otherwise combustible gases would simply go up the chimney and efficiency would decline considerably.
Starting at around 1100F and up entirely different processes start taking place. I don't believe it would be normal in a wood stove for these processes to exist to any great extent due to the very high heat, except possibly at the very low end. Gasification boilers operate in the 1100F and up range, with the combustion taking place in specially designed ceramic chambers that can withstand heat up to 2000F and more.
The combustion "flame" at this high end is not visible, and therefore cannot be said to be secondary combustion as usually understood. Carbon monoxide is igniting invisibly at about 1350F, hydrogen at about 1200F, about the same for acetic acid, methane at about 1100-1600F.
In a gasification boiler, the invisible combustion of these products is evidenced simply by a roaring sound - totally invisible. It also may be mixed with some visible, orange to blue, flame, with the flame being representative of other, lower temperature gases also being combusted.
- Status
Similar threads
