A small amount of oxygen does wonders… depending where you give it…
Its all about glowing Carbon… ( easiest way to explain )
Depending your “wood” , you’l have different proportions and variations of “chemical” compounds in your fuel feedstock.
Even some very different minerals.
And as they all get mixed up, heated, broken down… you have a melting pot of combinations.
Depending what vacuum, what temperature, what passing speed, the reactions will differ from one setup vs the other…
Some minerals in certain gasifiers will promote the generation of richer CH4 content and a higher Co2 level…
some will do this, other will do that…
One thing in common dough:
(extracted knowledge from Ol books ; Producergas and a Treatise on… )
KIS: Run your gasifier in balance between Hot glowing carbon in the reduction zone and “wet” wood as fuel…
( spoiler: wet wood is easier to gasify then dry wood as it transfer the heat better than dry wood )
Hence, the Thermal assisted reduction zone is “a must have” for good gasification.
Read the books, find the remarks in next picture and then love where the soot comes from in the WK gasifier/carburators
(spoiler: WK gasifiers have a good reduction zone proportion )
The Thermal assist would do not all the job from the reduction zone, but it most certainly will help it keeping its temperature…thus cleaner gas output.
A friend did send this to me…
I think it apply’s to many of us…
Lets share some dots…
Oddly, the first person that came in my mind, that fits the right part of the picture, was Kristijan…
Koen, love the “Tarry Matter” explanation and the “connect the dots” lesson!! (yes, that is Kristijan, a modern day Robinson Crusoe).
Matt, I didn’t even realize you could run hot gas into the engine. I’m guessing if one kept the gas hot and ran it through the engine though you would see a tremendous power loss due to less volume of gas being able to enter the engine? Any rough ideas how much power would be lost that way as compared to a cooled and filtered gas?
Looking back at this now. Just dont use wet fuel and you should not have anything to worry about.
In theory though you could power an engine with “dirty” gas so long as it’s hot enough to not let the tar condense? Obviously you would lose a lot of power density but in a tight spot might be a good get out of jam solution.
Well not exactly as I think the tar will make up for some losses as it will be more energy dense fuel. But yeah you can run hot gas, you will want to get temp gun to monitor the head temps. Wood gas runs cooler so you can get away with hotter gas going into the engine.
Oh wow that is really neat. Like you said earlier in the post why not just keep the gas hot instead of spending lots of money and time building a complicated system to “try” and filter out the tar. I have a few small engines laying around, maybe I’ll give it a go with hot gas and see what kind of results it shows. If it ends up wrecking the engine well they were free and not being used anyway.
You might want to look at page 4 figure 2.2 of this:
The boiling points for various tars:
Mixed Oxygenates (400C) → Phenolic Ethers(500C) → Alkyl Phenolics (600C) ->Heterocyclic Ethers(700C) → PAH(800C) → LargerPAH(900C)
For reference aluminum’s melting point is 660C.