Why do wood stoves make so much smoke?

[bholler]

Boy looks like the OP is very good at spending other folks money. I object to unfunded mandates and many of the proposed issues are unfunded mandates.

Sometimes there is lot to be said for the ignore member on this forum and this does seem another case.

What mandates did the op propose? To me it looked like they wanted the industry to do it on its own to avoid further mandates.

 

[bholler]

As far as requiring wood being sold to be dry. I don't think that is nessecary. But requiring sellers to test moisture content and disclose that to customers along with literature on proper moisture levels and burning techniques sounds like a good idea to me

 

[begreen]

Iv given up trying to explain this to some folks, otherwise intelligent people just cant seem to grasp this concept. Some will listen but i see guys burning for 10 yrs or more still burning wet wood(or trying to burn it).

I saw a YouTube video yesterday titled Everything You Need To Know About Burning Wood in a Woodstove. He was burning in a Regency and deliberately placed a green log on one side when building a fire. When the fire was completely burned down that log was still a big lump of charcoal.

 

[spirilis]

Harvesting firewood by thinning wildfire-prone forests is possibly the one situation where you can definitively call wood burning "carbon-neutral". The only thing better for the atmosphere, would be to keep the thinned biomass sequestered (in the form of lumber) and use other non-emitting forms of energy instead.

 

[Socratic Monologue]

As far as requiring wood being sold to be dry. I don't think that is nessecary. But requiring sellers to test moisture content and disclose that to customers

I agree. It is a simple fraud issue, isn't it? Perhaps legislation that defines 'seasoned' -- I'd suggest 'seasoned' means 'X percent (95% by volume?) of each purchase is at or below X percent (20%?) MC' -- could be put in place so that buyers could have some assurance they got what they paid for. I recall reading that some states don't allow the selling of 'face cords', likely for a similar reason.

 

[Seasoned Oak]

Outdoor smoke dragons. A crime against your neighbors and yourself.

Outdoor wood boilers

Outdoor wood boilers emit shockingly high levels of pollution.

woodsmokepollution.org

"OWBs Emit Shocking Levels of Pollution

At 150 feet away, OWBs were found to produce particulate level peaks of over 1,000 μg/m3, with frequent values over 400 μg/m3 during routine usage. At 50 feet away, a shocking 8,800 μg/m3 peak measurement was recorded.

To put this in perspective, when China declared Beijing’s first ever red alert for dangerous air quality, levels had reached 291 μg/m3 — a mere fraction of the hazardous particulate levels to which neighbors of OWBs are regularly exposed. "

Even EPA certified OWBs produce as much as 18 times the particulate matter as a regular EPA wood stove is allowed to.

 

[bholler]

I agree. It is a simple fraud issue, isn't it? Perhaps legislation that defines 'seasoned' -- I'd suggest 'seasoned' means 'X percent (95% by volume?) of each purchase is at or below X percent (20%?) MC' -- could be put in place so that buyers could have some assurance they got what they paid for. I recall reading that some states don't allow the selling of 'face cords', likely for a similar reason.

Yeah many states including mine PA require firewood to be sold in cords of fractions of cords.

 

[SpaceBus]

Outdoor smoke dragons. A crime against your neighbors and yourself.

Outdoor wood boilers

Outdoor wood boilers emit shockingly high levels of pollution.

woodsmokepollution.org

"OWBs Emit Shocking Levels of Pollution

At 150 feet away, OWBs were found to produce particulate level peaks of over 1,000 μg/m3, with frequent values over 400 μg/m3 during routine usage. At 50 feet away, a shocking 8,800 μg/m3 peak measurement was recorded.

To put this in perspective, when China declared Beijing’s first ever red alert for dangerous air quality, levels had reached 291 μg/m3 — a mere fraction of the hazardous particulate levels to which neighbors of OWBs are regularly exposed. "

Even EPA certified OWBs produce as much as 18 times the particulate matter as a regular EPA wood stove is allowed to.

Wow. I didn't know it was that high, especially for the new EPA OWB units. Are the IWB units the same way? I would think any gassification boiler would be fairly clean, so this is pretty eye opening.

 

[bholler]

Wow. I didn't know it was that high, especially for the new EPA OWB units. Are the IWB units the same way? I would think any gassification boiler would be fairly clean, so this is pretty eye opening.

Actual gassifiers are pretty clean. But most boilers aren't gassifiers. Really the only way they can burn clean is if they have a large amount of thermal storage and they are burnt hard to heat that water then shut down. If not burnt really hard the water jacket just saps so much heat they cannot burn very clean.

 

[Seasoned Oak]

Wow. I didn't know it was that high, especially for the new EPA OWB units. Are the IWB units the same way? I would think any gassification boiler would be fairly clean, so this is pretty eye opening.

Very different animal from an indoor gasser.

 

[Riddlefiddle]

Like I have said before, the EPA is just another tentical of the beast. They want control of the way you heat your dwelling. They can control gas or oil heat but not wood heat. That's why they have all of these emissions tests for wood stoves,Because they can't control who cuts wood.

 

[Sawset]

Like I have said before, the EPA is just another tentical of the beast. They want control of the way you heat your dwelling. They can control gas or oil heat but not wood heat. That's why they have all of these emissions tests for wood stoves,Because they can't control who cuts wood.

Do you live next door to an owb, or in an area of inversion. It's not some beast, it's your nighbors that don't like the way you smell.

 

[bholler]

Like I have said before, the EPA is just another tentical of the beast. They want control of the way you heat your dwelling. They can control gas or oil heat but not wood heat. That's why they have all of these emissions tests for wood stoves,Because they can't control who cuts wood.

And what have those regulations done to hurt woodburners? They have greatly improved the woodstoves we have available to us.

 

[Socratic Monologue]

Like I have said before, the EPA is just another tentical of the beast. They want control of the way you heat your dwelling. They can control gas or oil heat but not wood heat. That's why they have all of these emissions tests for wood stoves,Because they can't control who cuts wood.

I don't know of any EPA regulations that control the way you heat your dwelling. If you know of some, please cite them here.

EPA regulations control the sale of wood burning appliances. This is allowed, legally, in light of the Clean Air Act and its amendments. The Clean Air Act has been upheld by the courts, including the Supreme Court, often under the umbrella of the Commerce Clause of the Constitution. Yes, that Constitution -- the one people like to get all supportive of when it suits their perceived self-interest.

The "tentical (sic) of the beast" talk is fun and all, but researching the system of legislative justification in the United States might be a better use of one's time.

 

[EbS-P]

Back to the OPs question. Fire is just breaking chemical bonds. Wood has a lot and they are not simple molecules either. Methane has a very simple structure so when those bonds are broken you only get carbon-dioxide and water. The wood molecules break down into other molecules that are smaller and can still be broken up again (burned). The larger the molecules the less clean it burns think diesel va gas.
The need to burn in cycles makes it smokier. The temp drops and must rise again for complete combustion. Pellet stove solve the by continually feeding fuel. Wood stoves Don’t have that luxury.

second is there is no controlling the fueling rate so the air to fuel ratio needed for complete combustion isn’t always ideal. Fuel injection you have both independent air and fuel control. A carburetor has a set air to fuel ratio. Wood stoves well we can control some air flow. Nothing about the fuel. So it will run rich. Adding extra air only works if the environment is hot enough to burn the leftover fuel. Think secondary combustion but again if you don’t have enough air you won’t get a complete burn And you will get smoke. Adding air that is not hot will cause creosote condensation. I do think it is remarkable that the non cat systems today burn as clean as they do. Hope that helps.
Evan

 

[mnowaczyk]

Air quality. Delete my post if it’s too OT.

So wood burning, if clean and efficient, makes CO2 that will eventually be released into the atmosphere when the wood rots anyway. Right?

Burning the wood, if we have hot enough fires should just increase the rate at which the CO2 enters the atmosphere. Right?

But when we don’t burn it efficiently, it adds smoke and particulates that cause other air quality issues. Right?

I would assume that the larger the organization or facility combusting materials is, the more likely they are to be burning as efficiently as possible. Right? So a power plant is going to be more efficient than a wood fire. Right?

Is it more “green” for me to heat my house with natural gas in my mod con boiler (95% efficient?) with radiator heat? Or to add a little wood burning with my fireplace insert? I’ve been letting more and more wood rot as I’ve started assuming that I’m just hastening CO2 production if I burn wood.

I’ve got a back yard fire pit that I’ve used only once this year because it bothers me that it doesn’t burn as hot and efficiently as I’d like.

<begreen edit> Moved to thread discussing wood smoke effects. See post #7 in this thread about Nat. Gas.

 

[mnowaczyk]

Thanks for pointing me here. Post 40 resonates with me. I would love to be able to know exactly when to feed my stove and know that it’s a greener way to heat my home. I’m just not confident of that.

I see that outdoor fires are just bad. I guess they don’t have the tall flu that sucks in air to assure a good wind source of very controllable air. Last time I burnt a backyard fire, I found myself wanting to make a charcoal heater to get the wood burning faster. Teaching my kids survival skills conflicts with being as green as possible. Hmm...


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[SpaceBus]

Thanks for pointing me here. Post 40 resonates with me. I would love to be able to know exactly when to feed my stove and know that it’s a greener way to heat my home. I’m just not confident of that.

I see that outdoor fires are just bad. I guess they don’t have the tall flu that sucks in air to assure a good wind source of very controllable air. Last time I burnt a backyard fire, I found myself wanting to make a charcoal heater to get the wood burning faster. Teaching my kids survival skills conflicts with being as green as possible. Hmm...


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There are outdoor solutions like the Solo Stove products. I have their larger Yukon and small Ranger outdoor firepits. They are nearly smokeless and put out more heat than a regular fire ring or campfire.

 

[jatoxico]

second is there is no controlling the fueling rate so the air to fuel ratio needed for complete combustion isn’t always ideal.

If the OP seriously couldn't figure out why wood can't be burned as efficiently as NG I wasn't going to waste any time on it.

On the other hand it does bring up a topic I've heard here often which is that it most efficient to burn in cycles to which I disagree. Burning in cycles leads to cold/cool starts and (less importantly) finishes. Meanwhile tube stoves and cats both need to be hot enough to support secondary combustion so on reload you're smoking.

As long as I'm around I prefer to get the stove to operating temp and keep it there by adding fuel as needed and keeping temps up to burn clean.

Cycles may be more convenient but its not more efficient.

 

[Socratic Monologue]

Air quality. Delete my post if it’s too OT.

So wood burning, if clean and efficient, makes CO2 that will eventually be released into the atmosphere when the wood rots anyway. Right?

Burning the wood, if we have hot enough fires should just increase the rate at which the CO2 enters the atmosphere. Right?

But when we don’t burn it efficiently, it adds smoke and particulates that cause other air quality issues. Right?

I would assume that the larger the organization or facility combusting materials is, the more likely they are to be burning as efficiently as possible. Right? So a power plant is going to be more efficient than a wood fire. Right?

Is it more “green” for me to heat my house with natural gas in my mod con boiler (95% efficient?) with radiator heat? Or to add a little wood burning with my fireplace insert? I’ve been letting more and more wood rot as I’ve started assuming that I’m just hastening CO2 production if I burn wood.

I’ve got a back yard fire pit that I’ve used only once this year because it bothers me that it doesn’t burn as hot and efficiently as I’d like.

<begreen edit> Moved to thread discussing wood smoke effects. See post #7 in this thread about Nat. Gas.

Well, I don't think most power plants burn anything but fossil fuels, so that's the difference.

Burning cord wood is better than burning fossil fuels in terms of the long term carbon cycle (tens of thousands of years plus), which is the one that humans are mucking up most irreversibly.

 

[Socratic Monologue]

Cycles may be more convenient but its not more efficient.

I sincerely believe you, but I'm curious to know more. Do you have any links to research that supports this? It would be interesting to me to see this quantified, and maybe to tease out the relationship between efficiency and emissions as they are both affected by loading practices.

 

[jatoxico]

I sincerely believe you, but I'm curious to know more. Do you have any links to research that supports this? It would be interesting to me to see this quantified, and maybe to tease out the relationship between efficiency and emissions as they are both affected by loading practices.

Maybe I should set some parameters before making a blanket statement but not aware of any studies, more common sense.

If I cycle my stove with full load, I go from something like 250-300 then peak somewhere around 650-700. On the cold side I'm smoking because its too cool to support the secondaries so smoke is wasted. All you have to do is go outside and look. On the hot side I'm often getting more heat than I can use or even recover from my insert.

So I'd rather keep temps at 450-550 which burns all the smoke and gives me even heat. On a related note I have heard that most, or at least a disproportionate amount of creosote formation occurs during start up.

 

[Socratic Monologue]

Maybe I should set some parameters before making a blanket statement but not aware of any studies, more common sense.

If I cycle my stove with full load, I go from something like 250-300 then peak somewhere around 650-700. On the cold side I'm smoking because its too cool to support the secondaries so smoke is wasted. All you have to do is go outside and look. On the hot side I'm often getting more heat than I can use or even recover from my insert.

So I'd rather keep temps at 450-550 which burns all the smoke and gives me even heat. On a related note I have heard that most, or at least a disproportionate amount of creosote formation occurs during start up.

That all makes sense, and it sounds to me to be a sensible way to burn.

I wonder, though. There are stages in the burn cycle that your process may skip, stages that give more heat for less particulate emissions: for example, the coaling stage. Might that benefit be lost if the flue is always hot (so less efficient heat transfer to living space since more heat is going up the stack)?

All this will be different on different stoves, too; our Hearthstone will fairly quickly go to secondary from few coals since the firebox stays hot so darn long. I'm not saying that it is a particularly efficient stove, but it does likely burn differently than your insert, and so maybe this is as much about stove design as it is about burn cycles per se.

I couldn't find any readily accessible data on relative efficiency of differing burn cycle models; emissions testing sometimes notes that data are averaged over the whole burn cycle, which might be taken as an admission that we don't know (or don't care?) what is happening during the burn cycle. There's a good dissertation topic here, I tell you.

 

[jatoxico]

I wonder, though. There are stages in the burn cycle that your process may skip, stages that give more heat for less particulate emissions: for example, the coaling stage.

Its not like I never run through the coaling stage. But I find by adding as needed I can easily manage the coal bed. So I just try to keep my eye on the temp and reload before my stove top temp runs below about 400. To me its just a matter of trying to run within the window where the stove burns clean. Keeps the room temp more even as well.

Pellet stoves are, in some respects, doing the same thing I am. Metering in the amount of fuel and air to maintain optimal combustion and maximum efficiency. I guess BK stoves are doing this too.

There are times and situations when I need more heat or not around but as far as I'm concerned, in concept getting the stove up to and keeping it at operating temp is most efficient compared to cycling.

 

[Alexx]

Natural gas used for residential space heat is a fairly small portion of the natural gas burned. More is burned to make electricity and for industrial uses.
I might be wrong, but I believe a lot of natural gas is just in the way of the oil we want and not really the main goal of fracking.
I like the idea of burning wood and grass pastures, but using a wood stove puts the smoke in proximity of people. A cleaner way to burn wood might be in a hot compost pile using bacteria instead of flames.