Gasification Arch Design

[saekeaton64]

I have been thinking of a new design for an arch. It is a hybrid design between a downdraft gasifier and a standard arch.
The reason for the downdraft is that it creates extremely high temps. 2000+ degrees. Also, being a gasifier, it will reduce the smoke from the arch.
The gasifier design was taken from a Outdoor Furnace.
Currently I have the arch to be a 24" x 72" or (2' x 6'), the firebox is 24" x 24" x 24" and is insulated with castable refractory cement.
The area at the top of the arch where the pans sit, will be skinned in sheet metal and insulated with ceramic cloth.

The design is pretty straight forward, the firebox is sealed on all sides except the bottom. Air is injected into the firebox by a blower fan mounted on the door of the unit.
The air is forced through the elongated slot at the bottom of the firebox creating a blast furnace effect. The heated air and ash then travels towards the front of the unit
where the ash is left and the air turns around and heads to the back of the unit. Traveling up along the back of the firebox and hitting a deflector plate, again forcing the air
to the front of the unit. The air then travels under the pans and out the flue.

Any feedback on the design would be great, I don't really know if it would be worth all the extra work in creating a unit like this, but maybe.
Attached is a link to a video better explaining how the gasifier works.

Thanks,

http://youtu.be/kJkNm6517bg
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[Mark]

I have a gasifier that I built for my evaporator, it is a horizontal one. Mine is close coupled and the secondary combustion chamber is under the syrup pans. With your picture you would not get any radiant heat from the fire on the pans.

We just had a wood stove installed last year and it works like that. Good stove but I think it would not work as well for an evaporator but it would be worth a try and see what happens.
http://www.froeling.com/en/products/firewood/froling-s4-turbo.html

[saekeaton64]

In the design, there isn't any insulation on the top of the firebox and the deflector plate is simply plate steel. This should all these areas to heat up and radiate on the bottom of the pans. With the gasification taking place under the firebox, all the smoke should be burnt up, leaving the bottoms of the pans much cleaner than a conventional design.

I would really like to see a few more people chime in on this. Do you think it would work or not? Any design changes needed to make it work better? Scrap the idea and spent time and money to build a conventional arch?

P.S. I intend to use a 2’ x 2’ syrup pan in the front and a 2’ x 4’ drop flue or drop tube pan in the back.

[Mark]

If you have a deflector plate with heat on both sides it will not last long.

[nymapleguy607]

Its a good idea, but I don't think it will give you the results your looking for. Typically the down draft gassifiers are used to heat water for large boilers on those you only need to heat the water hotter than what you want the your house set at. For an evaporator to boil hard and efficient it takes both the hot exhaust gasses but also the flame to get the flue pan to boil. Your typical stack temps on wood fired evaporators run generally between 800-1000 F some people run hotter. Look at CDL's Intense-O-Fire arch and the Lapierre Force 5 they are a pretty good example of efficient wood evaporators.

[saekeaton64]

The deflector plate is designed to be made from ¼” plate steel. I think it should withstand the heat without melting or burning away, but it may warp badly.

I redesigned the plate to have angle iron welded across the top to resist the warping effect and maybe create a turbulent flow redirecting the heat towards the syrup pan.
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[tuckermtn]

the high efficency arch I had built last year on 802maple's design relies on cool air running on one side of any exposed metal inside the firebox (except the stainless pans of course) and where cool air cannot come in contact with metal it is insulated with ceramic blanket. Any exposed metal that does have cool air or some sort of insulation on it does not last long.

I have air coming under fire through drilled fire brick, from the back wall of the fire box, from the door through the hinges, and just under rails where the syrup pan sits. The arch just rips...I don't try to run it for longer feed times- I run it for maximum boil. doubled my evaporation rate with the same set of pans. stack temps 1000 deg.

[RyanB]

Bringing back this older thread.... Deffinatly intrested is gassification and am curious about the design that the OP came up with and if anything ever became of it? I too am thinking about building a new larger arch and pan set (thinking a 3x10 or 3x12). I figure its worth the option to explore the use of gassification over just going with AOF and AUF and the pay off in possible fuel savings could be benifical. If the main burn chamber is under the syrup pan and the secondary chamber is under the dropped or raised flue pan is there any reason this couldn't work? From the flue pan the heat and exaust gasses could be channeled down under the the secondary camber where it could run thru a heat exchanger in order to heat up the incoming compressed air for combustion then channeled again to the back of the arch and up the stack. This would get the stack temperatures down ALOT, heat up the incoming air/oxygen, give standard temp heat over the syrup pan and give that super hot gassification heat to the flue pan.

Possible? I am just trying to wrap my head around how the big guys can get the temperature numbers they are getting yet get the stack temps down so low....that heat must be going somewhere and the only 2 places I can possible think of other than going up the stack is to heat incoming air or heat sap pre-pre heater thru another heat exchanger.

Just doing some thinking....Ryan

[saekeaton64]

Sorry to say, but I haven't done anymore work on the gasification design this year. The season has kept me very busy, but is now coming to an end down here. I think I have a pretty good idea of the design you are describing and I think that it may work very well. It will allow for direct heat under the syrup pans, and super heated gasification under the flue section.
Give me a little bit and I'll try to get some new drawings using your concept posted.