This is what gasification means??

[muncybob]

Found this statement on a OWB web site.....
In simple terms, gasification strips and burns combustible gases off the wood before the actual wood burns. This method results in approximately 30 percent less wood usage than conventional wood furnaces.

A bit misleading, no?

 

[tom in maine]

Isn't that what all wood burning stoves/boilers do?
You take a chunk of wood and make it into a gas.

The wild card is how complete the combustion is. No?

 

[Nofossil]

I suppose technically ALL combustion involves gasification, since solids and liquids can't generally burn.

In the context of biomass, I understand gasification as a process involving two distinct and separate steps:

1) Pyrolysis (wood gas generation) in which combustible gases are produced by heating the wood in the absence of sufficient oxygen, and

2) Secondary combustion, where those gases are mixed with fresh air and burned.

An important consideration is that the secondary combustion zone allows turbulence / mixing of the fresh air at VERY high temperatures with enough time for combustion to complete.

This does result in a dramatic increase in efficiency, since virtually all of the fuel is consumed - no unburned hydrocarbons going up the chimney.

Unfortunately, there's no standard that I'm aware of that defines what may or may not be referred to as 'gasification'.

 

[DaveBP]

Regardless of what a term might mean, once it becomes common, the salesmen will take it and misuse it to the point where it becomes confused and soon meaningless.

 

[bigburner]

if flue gases were measured then a relative number could be assigned to over all process. Maybe a downdrafter is a 2 and a green wood is a 4 and an OWB new style being a 8 and the old style being a 99.

 

[Singed Eyebrows]

Found this statement on a OWB web site.....
In simple terms, gasification strips and burns combustible gases off the wood before the actual wood burns. This method results in approximately 30 percent less wood usage than conventional wood furnaces.

A bit misleading, no?

I'm not sure whats left after the gasses are driven off & how this then "burns". I think after all the gas is stripped off you ain't got no wood left or at least very little, Randy

 

[tom in maine]

Found this statement on a OWB web site.....
In simple terms, gasification strips and burns combustible gases off the wood before the actual wood burns. This method results in approximately 30 percent less wood usage than conventional wood furnaces.

A bit misleading, no?

I don't buy the gases burning off before the actual wood burns. The wood is turned to gas. Period. How well that gas is burned is the issue between what is a " gasifier" and everything else.

When I mention the word gasifier to Dick Hill, the "father" of the wood gasifier concept, he rolls his eyes since all wood burning is gasifying.

The 30% part I can buy, the explanation is flawed.

 

[muncybob]

Found this statement on a OWB web site.....
In simple terms, gasification strips and burns combustible gases off the wood before the actual wood burns. This method results in approximately 30 percent less wood usage than conventional wood furnaces.

A bit misleading, no?

I'm not sure whats left after the gasses are driven off & how this then "burns". I think after all the gas is stripped off you ain't got no wood left or at least very little, Randy

Well, that's what I thought. They even claim to run downdraft when using dry wood and updraft when using green wood.....that's another confusing statement to me. Interesting what companies say to sell their products, huh?

 

[Singed Eyebrows]

Found this statement on a OWB web site.....
In simple terms, gasification strips and burns combustible gases off the wood before the actual wood burns. This method results in approximately 30 percent less wood usage than conventional wood furnaces.

A bit misleading, no?

I'm not sure whats left after the gasses are driven off & how this then "burns". I think after all the gas is stripped off you ain't got no wood left or at least very little, Randy

Well, that's what I thought. They even claim to run downdraft when using dry wood and updraft when using green wood.....that's another confusing statement to me. Interesting what companies say to sell their products, huh?

Yeah Bob, I run updraft gasification when starting & downdraft afterwards, lol. Randy

 

[Rick Stanley]

Guess that makes mine a sideways draft

 

[Singed Eyebrows]

My take on this is that a gasser is just a slow gas producer & doesn't allow unburned gas to go up the chimney. There is nothing special about what is happening in the gasser primary chamber except a slow burn because of controlled air. There is not more gas produced in a gasser than any other wood stove as previously mentioned./The rest is just good mixing & proper placement of the secondary burn, Randy

 

[Singed Eyebrows]

Good Mixing?

 

[Singed Eyebrows]

Good Mixing?

yes, good mixing + minimalized exsess combustion air

You still don't reach stochiometric with a non Lambda boiler though Earl. These aren't that precise as evidenced by Nofossil's boiler huffing, mine making a real fast chattering noise at times etc etc. Randy

 

[711mhw]

Found this statement on a OWB web site.....
In simple terms, gasification strips and burns combustible gases off the wood before the actual wood burns. This method results in approximately 30 percent less wood usage than conventional wood furnaces.

A bit misleading, no?

I don't buy the gases burning off before the actual wood burns. The wood is turned to gas. Period. How well that gas is burned is the issue between what is a " gasifier" and everything else.

When I mention the word gasifier to Dick Hill, the "father" of the wood gasifier concept, he rolls his eyes since all wood burning is gasifying.

The 30% part I can buy, the explanation is flawed.

In a woodstove without grates u end up with belligerent coals. why?

Does it not seem that by the time you get your wood burnt down to a "coal ish" log that the gasses may be spent. It deffinetly burns differently and seem not quite as hot as when the wood is earlier on in the burn. This seem somewhat believeable. ??

 

[DaveBP]

Does it not seem that by the time you get your wood burnt down to a “coal ish†log that the gasses may be spent. It deffinetly burns differently and seem not quite as hot as when the wood is earlier on in the burn. This seem somewhat believeable. ??

The combustion chemistry just HAS to be more complicated earlier in the burn. Doesn't it?

By the time you get down to "coals" (assuming we're all talking about the same thing) there's not a lot more than carbon left. Burning carbon is a lot simpler formula.

Carbon+Oxygen=Carbon dioxide and Carbon monoxide. Only two possiblilties.

If you are using a true gassifier with refractory afterburner and temp and air settings are right there probably isn't a lot of carbon monoxide going up the stack.

 

[pybyr]

Found this statement on a OWB web site.....
In simple terms, gasification strips and burns combustible gases off the wood before the actual wood burns. This method results in approximately 30 percent less wood usage than conventional wood furnaces.

A bit misleading, no?

To use a technical term, the above is about blowing smoke.... Any non-gaseous fuel needs to be vaporized before burning; gasification boilers are merely carefully designed to accomplish destructive distillation and controlled carburetion.

 

[Der Fuirmeister]

Regardless of what a term might mean, once it becomes common, the salesmen will take it and misuse it to the point where it becomes confused and soon meaningless.

Kinda like a politician.......