Thierry, you mean with the Fischer-Tropsch synthesis? Yes, l obtained a sample. My setup was realy small and crude. It was my graduation project. I am still gathering information and courage to do it again on a larger scale thugh…
Koen, looking fantastic! I like the term electric gasifier. I bet even raw wood culd be gasifyed this way.
Haha, l saw that on your 360° video 
your smile sayd it all
Any updates or new developments with this project Koen? I had a similar idea for cracking tar, just using an induction heater instead of a resistance heater. Like this one http://inductionheatertutorial.com/. A resistance heater like yours probably makes more sense though, simpler power supply. Plus resistance heaters are more efficient for a long run time.
You should look up the Riche’ retort gasifier. It’s a french gasifier from the late 1800’s, early 1900’s. As I understand it, it’s the same general concept that you’re going for with a zone of glowing hot char heated by an external energy source to crack tar. I’m hoping to build one in the near future. I might do a thread just on the original, just as an informative thing, and do a separate thread of my actual build, if and when I get to it.
Kristijan, I’ve done the same thing with my welder using gouging electrodes. Honestly a welder isn’t quite up to the task. While most will provide the 35 volts needed for a stable arc (not the little 125 VAC ones though), no welder I’m aware of will be able to create an arc at 100 volts or more. That would produce a nice long arc giving more energy to the electrons, and effectively increasing the surface area being heated by radiant energy. I’ll have to see if I can dig up an old patent I saw, I think it explains it better. Something from the 50’s or 60’s dealing with coal gasification.
As far as the life of the electrodes, if you know how to do any kind of electronics, an auto feed system wouldn’t be to hard to make. A comparator would read the voltage between the electrode and ground. As the rod burns back the arc gets longer and the voltage climbs (we’re using a constant current power supply), when the voltage hits a specified point a feed motor turns on pushing the electrode forward. Once the arc is shortened and the voltage drops the motor shuts off. if the voltage is too low, the motor kicks in reverse. Add an electrode magazine and every time an electrode runs out, another is ready to go. Or you can try to do what the big boys do and have an electrode extruder. Makes the electrode as it’s using it. If you make charcoal, you have the ingredients, raw powdered carbon (charcoal) and heavy tar. You’ll need to pyrolyse your wood and collect the off gasses, then distill that until you have the really thick, gummy tar. The kind Norwegian’s like to eat (no joke). Mix it up, put it in a hopper, heat it to make it soft, feed it through an ectruding device, heat it even more to cook off the tar and that’s it, as I understand it. The heat to cook off the tar can even be the heat from the arc as you’re using the electrode.
Not to get off topic, but an idea for either one of you since you like to experiment, large industrial facilities use “cold” plasma to crack pollutants, including creosote, in their smoke stacks. Cold is a relative term, it’s still screaming hot. Basically all it’s just an array of Jacob’s Ladders (the arc machine in mad scientists labs) that the gasses pass through. All you need is a transformer for a neon light, and a healthy respect for very high voltages. Then figure a way to put it in the outlet of your gasifier. Should be more efficient than trying to crack the tars by brute force like the two methods above, where you’re supplying enough external energy for gasification plus cracking. The “cold” plasma just supplies enough external energy to finish cracking what the gasifier missed.
I can not find anything on the internet about this system. Do you have information to share?
Some books.
A treatise On Producer-Gas and Gas-Producers by Samuel S. Wyer. Page 215
Gas Engines and Producer Gas Plants by Rodolphe Edgar Mathot. Page 190
A Text Book on Gas, Oil, and Air Engines by Bryan Donkin. Page 235
Found them on Google play books. Some have multiple editions, try to find the ones with the latest publishing date.
"The only exit of the retort is at the bottom, and in travelling down through the retort the gases pass through the lower bed of fuel, which is at a very high temperature, being practically in a state of incandescence.
Any condensable gases or vapors in this part of the retort are broken up and fixed so that the gases which pass through the U– shaped pipe L to the holder K are in the condition of permanent gases. When wood is used as fuel the composition of these gases is about 18 per cent, carbonic acid, 22 per cent, carbon monoxide, 15 per cent, methane, and 45 per cent, hydrogen."
I did not know that the place where the gas was taken from the autoclave affected the quality of the gas.
should the quality of the coal produced also be influenced by the location of extraction?
I presume that the gas extracted at the top of the horn (vs. gas extracted at the bottom of the horn) reduces "the work
dissociation "tars and vapors from wood distiation
Less work means less energy and faster carbonization
can also be coal with less tar residue ?
Thierry
The bottom of the retort is heated to cherry red, the charcoal inside that part should be hot enough to glow. The glowing hot char cracks the tars as they pass through. Same idea as Koen’s electric heater, the “devil’s mouth.” Red hot char cracks the tar.
The books I listed describe it slightly better than the website Gary linked. Just slightly. I had to read the short descriptions a few times to catch what was actually going on. I’m on vacation and only have my phone, otherwise I would have started a thread with screen shots from the books and such. I’ll try to put together a detailed description, as best as I understand it, by Wednesday or Thursday. It’ll probably be under the charcoal section, even though technically charcoal is a byproduct. But I know a lot of people who make charcoal wish they could put the off gasses to use some how.
I don’t know if less tar would require less energy input or not. The books suggest the temperature might climb, and actually recommend using wet wood, 40% moisture. The water gas reaction is endothermic and might even be necessary to control the heat. Like I said, the descriptions were brief. But this thing is a tar splitting machine. The first Riche’ plant made actually ran off of petroleum. So if you have low tar material, why not just gasify it in a more conventional method? Use the Riche’ for problematic feedstock. That’s what he designed it for.
But if you consider the composition and energy content of the resulting gas, it would be a high grade engine fuel and feedstock for Fischer Tropsch processing.
Yes it is high grade. The books I listed all day it has about 2.5 times the energy per cubic foot as other producer gas. As far as Fischer Tropsch, that’s out of my league. My plan is to have a Riche’ type unit for a stationary cogeneration set up, then use the charcoal for mobile applications and biochar. I have access to a LOT of hemlock, which is in the pine family, so I’m hoping to possibly make pine tar or bio oil as well. Which I suppose, now that I think of it, could be run through again later to produce gas on demand. Hmmmm grey cells are starting to run amok.
Sorry if I’ve hijacked your thread Koen. I’ll try to start another one tonight, even though I don’t have the files and stuff with me that I wanted to put in it.
to crack the tars of the distillation of the wood it is necessary to expose the tars with very high temperature and a certain time
can we reach these temperatures with a wood fire? and how should the bottom of the autoclave be built to withstand these thermal constraints?
Apparently. It’s an actual documented gasifier. Hundreds of them were built less than 120 years ago.
I started a thread under charcoal. I’ll post all the info I have about it there in a couple of days.
I’m sorry you have to wait. I know you are eager to know more. It’ll probably just drive you crazy if I told you that there’s a second design he made. 
Though you may have seen a smaller more “modern” version of it. Besides the retort gasifier, there was the Riche’ Combustion gasifier.
Check out post 20 and 21. Not specifically a Riche’ Combustion gasifier, but it embodies the main idea behind it. The charcoal reduction filter. Heat from the burning wood gets the charcoal hot enough to crack the tars.
And if you pause and think about it, any gasifier that puts out low tar/tar free gas pretty much has to have glowing char in it, unless you have pure carbon fuel, or an extensive filtration system.
In a standard combustion based gasifier the products in the pyrolysis zone really aren’t any different than the distillation gasses. It only takes them a moment to pass through the hot coals. Granted there is oxygen present to support partial combustion to supply the heat needed. With the retort, the same heat is being supplied by an external source instead of an internal one.
That is the essence of any good gasifier… having sufficient glowing charcoal in a layer to pass all tar and gasses, to be reduced into good quality woodgas…
and; cherry red isn’t hot enough to do the job 
My research / development is actual focussed on the glowing carbon as “catalyst” for tar and much more…
How to do it and what materials are available to do the job, is quite the challenge…
the hype “biochar” ought to be abolished as a usefull way to sequester GHG… Biochar should be used as energy source instead of any fossil fuel…
Biochar+Water+Co2= a great replacement for any known fuel ( based on fossil ) there is now.
And with a lot less pollutants since the synthetic fuel is much more pure…
as in the original start of this topic, V1, i might be now at V9 or 10… past the original testing and now working on the follow up’s…
Lots of fun with hot glowing materials…
Hi Koen
do you mean that the gas coming out of a “Riche” still contains tar and can not be used in an engine ?
Hi Thiery,
the words to look for “carbonic acid” in one way and insoluble tar’s the other way…
if however a glowing charbed at high temperature could be created at the bottom, beforehand, and maintained during the batch process, then all tar would be cracked as would the carbonic acids.
That temperature would be above 1300ºC
ad some oxygen in the carbon in the Riche retort to compensate the endothermic reaction from reducing the tar fraction does the trick… 
Might explain the strange experiments i perform ? anyone ?
The retort is supposed to be preloaded with some charcoal in the bottom and brought up to temp, then wood was added. But it seems it was a continuous feed system of sorts. Every so often the charcoal at the bottom was removed and fresh wood added at the top. Don’t know if I’d want to be the guy with that job. Thank goodness for modern automation.
You actually make a similar argument about temperature as someone quoted by the author of one of the books. And yet the Riche’ Retort apparently worked. From my own reading about autothermal reforming and gasification, 800-900° C seems to be just fine for the temperature to crack the tars. Not trying to argue. I am a noob, just saying the design and operation was already proven a long time ago.
But who knows. The definition of clean gas could have been a little more loose back then. Maybe 1300°C is necessary to clean it to today’s standards.
Think you could share the results of some of your tests with the device you made? If you can’t because it’s a trade secret, I understand.
1500 2000 f degree seems too work just fine, a well design hearth too match too motor size, wood size, dry the wood enough, and choke sized. and as you said a good size charbed, no tar cracker needed. oh and recycle the heat around burn box and or heat exchangers.
Yup, i am reading the book on Google , thanks for pointing out, stating 1652ºf, what equals 900ºC.
The "cherry red " does cause some misunderstanding ( for me) leading to confusion about the actual temperature ( colors are more subjective )
Riche also injected air when there was Tar present in excess.
The Charcoal (carbon ) , if the retort system is well designed, is consumed in the process of reduction. ( only ashes out ) or leftovers are sorted out to reuse…
Depending the temperature ranges working in, the glowing carbon strips the O’s from the nasty’s and form CO ( nuttshell explanation )
If you check this clip, then you see the reduction of the CO2 starting at a certain temperature and nearing complete at 1250ºC ( input gas was 100 % CO2 ) at the end i did have the insert probes molten (stainless steel) as well the Kanthal heating elements…
Thats cool hot research equipment you have there. how well do bambo priolisize in the wood gasifoer mode. would you say that bambo is harder too drive on than wood in a wood gas truck system like WK trucks. ?? Thanks
