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how to make charcoal

 
Posts: 1502
Location: Chihuahua Desert
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from many sources I have found, wood gas requires 30-45 lbs of wood per gallon of gasoline equivelant.  Here is an open source gasifier for vehicles:
http://www.gekgasifier.com/

The best way to make charcoal is a retort, which can be made from a variety of materials.  Wood starts the cooking process, and then the pyrolysis gasses take over and heat the wood after that.

Here's an easy example:
http://www.holon.se/folke/carbon/simplechar/simplechar.shtml
 
Abe Connally
Posts: 1502
Location: Chihuahua Desert
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another thing to consider is grinding and making biochar/fuel from wastes, like corn cobs, rice hulls, grasses, weeds, prunings, etc.

I think that has a lot more potential than cutting trees for fuel, unless you are using a coppiced crop.  I've seen yields anywhere  between 3-15 tons of biomass per acre per year from coppiced fields.
 
                        
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"Beaver Energy is the home of the Worlds Fastest Wood Powered Car (technical category: solid organic material). On September 17th, 2010, Beaver Energy set the World Record at the Bonneville Salt Flats in Utah during the 24th Annual World of Speed. The speed was set at 47.74271 MPH. We hope that during next years World of Speed we’ll have some competition to break the record, we know we’ll be back with a much faster car."

a quote from a forum post suggesting that people from this site could do better..
http://wiki.gekgasifier.com/w/page/6123754/How-to-Build-and-Run-the-GEK-Gasifier
 
                        
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Jonathan_Byron wrote:
One note: making both wood gas and charcoal can result in significant carbon monoxide production ... a potentially serious health issue if one stands in the wrong place too long.


One of the things which is emphasized by responsible people re making biochar is the necessity of NOT letting smoke from the pyrolyisng chamber escape uncaptured or burned. Carbon monoxide is only one besides methane and other volatiles which need to be dealt with or the thing is an incredibly negative process, leading some people to have as their mantra  "don't make this at home" as people are often lazy about such stuff.


 
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Geof Moxham called the biochar an "Underground Coral Reef" for soil life.
I like that...
 
pollinator
Posts: 761
Location: Federal Way, WA - Western Washington (Zone 8 - temperate maritime)
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I love this!  And the only way I can see to convert the heat to thermal mass for greenhouse heating is by using water.  I plan to try heating up some overed pots of water to put in the GH on a cold night, and see how effective it is.  But some genius must have come up with an easier way to do the same thing ;

And, might not soaking char in urine achive the bio-charging... and hopefully circumvent a .. 2 year! ... aging period?
 
Posts: 244
Location: Caerphilly, Wales, UK
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forest garden trees woodworking
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As the bloke who showed me how to make charcoal said, any wood that isn't converted to charcoal by the end of the burn makes REALLY good firewood.
 
Posts: 257
Location: Nicoya, Costa Rica
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One thing that puzzles me about charcoal is that all the sources I've come across so far say in the same breath that charcoal is good for filtering the soil of all poisonous stuff and that it's good because it retains nutrients; I can understand how that can be like that, due to its structure, but I also feel like wondering: which is it?

For example, in the farm where I live, the peones have cleared some forest to plant more rice, and they sprayed herbicide, then they burned all the dry brush and weeds. Now where they burned, the rice is clearly darker green and taller. Same happened where they planted corn and there is an area where I could harvest a bunch of charcoal to infuse with compost tea and what not, but isn't it already soaked in herbicide or residual nasty stuff? If the benefits of biochar last for hundreds of years, what about the negative side?
I guess my first answer is that the capacity of biochar to harbor life due to its structure is what lasts forever, but all the good or bad chemicals in it do break down in time, as well as the colonies of MOs are replaced by new generations.
Right?
 
                        
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what an interesting question!  And one that I haven't seen addressed or investigated at all anywhere so maybe someone will have  some info about this. 

My first thought is that if charcoal lasts virtually forever, the residue that soaks in may be in a form less accessible to the plants and the value lies in the habitat it provides for the microbial and other minute life of a healthy soil. In other words, the innoculation or "weathering" period  to prevent charcoal from taking in nutrients from the soil initially may only actually be a sort of stabilizing time, and once stabilized the charcoal isn't actually providing anything directly to the plants but indirectly through the action of its tenants.

Certainly charcoal is a traditional material for taking contaminants OUT of water and such, how long it sequesters them and if it ever releases them back into the environment  is a very good question. I hope someone knows of some good research that points to an answer.

 
Sergio Santoro
Posts: 257
Location: Nicoya, Costa Rica
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OK, what am I doing wrong. Here are two pictures of my retort at its second burn (as we speak).

I followed pretty much the design I've seen on youtube. One of them is on page 1 of this thread.

As you can see, the flu pipe and lid fit loosely, so there is air feed, but my retort doesn't have a raging fire all the way to the end. When the kindling is done, it starts making smoke and it takes hours to finish the burn. I still get charcoal (out of rice hulls, btw), but I understand it creates a lot of pollution and lesser quality charcoal.

One thing I guess is that there is not enough air circulation and pull, so the fire chokes. What I don't understand is, if charcoal is combustion in absence of oxygen, whouldn't all that air circulation foster the kind of combustion that makes ash?

Anyway, please take a look at the pics and let me know. I made as many slots at the bottom of the drum to equal the width of the flu pipe opening, but rice hulls allow for less air circulation than wood sticks. Is that what it is? Because if I drill more holes and that's not what I had to do, it's going to be hell to patch them...

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pollinator
Posts: 1528
Location: zone 7
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if your charring rice hulls try this method.

much much better.

http://www.youtube.com/watch?v=qH4BzVp6wpU&feature=related

you dont even really need the stack. just start a good fire to get some coals going. smother with a huge pile of rice hulls, when you see black spots cover them. when its almost done follow the same method the guy in the video does where he turns and then puts it out with water.
 
Sergio Santoro
Posts: 257
Location: Nicoya, Costa Rica
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Thanks, I'll definitely keep this in mind, but right now we're in the middle of the rainy season here and I couldn't do that. Also, it seems to make a lot of smoke.

I'm pretty sure that by adding more holes in the bottom my retort will improve a lot.
 
                        
Posts: 508
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ARGH.    I wonder if the guy in the video has any idea at all how much really evil pollution..methane etc he is dumping into the air?  A little knowledge is a dangerous thing.. various places have banned wood stoves because of pollution, the worst wood stove ever  has nothing on that way of making char.

Sergio... you have got yourself a bit of a challenge using rice hulls because they behave differently than wood chips do. One government bulletin suggest agitating them in the process  because they are so uncooperative  but that's pretty tough to do in a home set-up.    It looks as though you are using the flame on the top of the rice hulls? If so,  for this sort of material you might have done better with a different design, something like this
 http://www.youtube.com/watch?v=RXMUmby8PpU  or for a simpler version
 http://www.holon.se/folke/carbon/simplechar/simplechar.shtml

However, since you have the system you have, there's a couple of things you might try. Perhaps  try putting a layer of sand or ash over the top of the barrel to insulate it some so as to try to get the barrel hotter.  Or you might try putting a secondary fire chamber on the lid in a container between the barrel and the chimney stack. (a metal bucket or even a small brick structure?)  to see if that helps with the draw. Another thought is to try to extend the height of your chimney. Or all three   Something else you might try would be to raise the lid of the barrel a little by putting a couple of pieces of rebar across the barrel under the lid. Might be worth a try before you start remodelling your barrel.  Draft and air supply is super important to getting things working right. 

 In any case, what you are doing now is a whole lot better than the  guy with the pile of rice hulls  smoking up the neighborhood.
 
Sergio Santoro
Posts: 257
Location: Nicoya, Costa Rica
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Thanks! The replies are getting more and more helpful.

Here is the thing, though.
Yesterday morning I emptied the drum that had been done since 1am so there was a lot of ash. Last night I was right there when the burn ended, so I tipped the drum right away and I got virtually my 55 gal drum of rice hulls worth of charcoal, no reduction. It did take 8 hours instead of one, and it made smoke all the way.

I'm saying this because I was familiar with Peter Hirst's video, but out here I can't find any drum that's larger than 55gal, and any smaller drums are shorter and thinner, so I'd get so much less charcoal. However, thanks for posting that video, because in the related videos I found another one that I was after, but thought it would be impossible to find again among the many biochar videos.

Check out this design. It seems it would work better with rice hulls (I had no idea rice hulls were so peculiar, but it's what I get in abundance here, especially until the rainy season is over, but even then, rice hulls are just the right size for gardening, I don't have to break the bits...).

http://www.youtube.com/watch?v=nQxIXDo-egA&feature=related

I'm also thinking of this variation: instead of running the pipe through the drum, and instead of keeping the rice hulls fluffy, I'll load the drum with sawdust and rice hulls and compact the heck out of them around a central pole, that I would then remove, creating a rice hull chimney. Then I'll have a fire under the drum, that will go through the rice hull chimney and through the pipe on top of the drum. How's THAT for draft?
Here's what I'm taking inspiration from.

http://www.youtube.com/watch?v=GzGvAMIY3lc&feature=BFa&list=WLEF4B226B61F13644&lf=BFp

It has to work. I'll let you guys know.

PS Forget the sawdust; they charge me for it at the mill, while the rice hulls are free. If the hulls don't do a good job at compacting, as I suspect, I'll make a paste with hulls and cow dung around the central pipe and compact that. Oh I'm excited!
 
                        
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If I may make a suggestion..if you want to do something like this, you need not take the chimney out at all, nor compact the hulls  (they will do that on their own )  You can sit the barrel on some rocks or bricks  (make sure it's stable obviously!)  so you can light a fire under the barrel but the smoke has nowhere to go except up the chimney. Then punch a few holes in the BOTTOM  of the barrel so the escaping gasses  have nowhere to go but through the fire .  The smoke still goes up through the chimney in the middle of the stuff you want to char (like a rocket stove, sorta). The heat from the fire roaring up the chimney should char your hulls (the top has to be sealed except for the chimney of course).You also then wouldn't have to worry about the hulls collapsing into the chimney hole and plugging things up. 

This will work best if you can somehow manage to insulate the outer shell of the barrel..cob maybe, if you are in an area which offers that, or brick..  anything to get the heat up in the charring area and keep it there. Might need to do this on only three sides so you could get the barrel OUT  to dump it tho:)

This SHOULD give you char of almost the same volume as the material that went in; the disadvantage being that you need to make sure the fire keeps going fairly enthusiastically throughout the burn.  I suspect that if you just use the sawdust stove system in the video you will end up with mostly ash.. as far as I can tell those  are being used to cook with and really are just a form of normal contained fire..the air comes in below, and combusts. 

There is another video of a guy using two or three drums of the same size as TLUDs ..one at the bottom for the biomass, one cut in half which sits on top and acts as an afterburner, sort of  and has lots of air holes, and the third as a chimney but again, he is using wood scraps, not rice hulls. Still if you want I will look it up and give you the link.
 
Sergio Santoro
Posts: 257
Location: Nicoya, Costa Rica
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I know the video. It's on page one of this thread. Why would the stove produce mostly ash again?
 
                        
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The sawdust stove? What's to stop it from just burning like any other fire? There isn't any way that I saw to prevent the  stuff from simply just burning..there isn't anything there to give you the airless chamber that is the basis for char.  Or were you thinking to try to empty it  half way through the burn and see if some of it had charred while waiting to get burned? It might have, maybe....sort of like putting out a campfire that still has lots of wood left to go..I suppose that's really closer in some ways to the way that terra preta was originally made..   keep us up to date on how that works for you!
 
Sergio Santoro
Posts: 257
Location: Nicoya, Costa Rica
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Well, in the last video you recommended, the guy has air sucked in from the bottom, flowing through the wood chips, burning at the top and escaping out of the chimney, and he said that if the draft is strong enough he can make charcoal in one hour. So which is it? Air flow or airless? That's where I get confused.
 
                        
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no.. the video  I showed you the material in the inside barrel  doesn't touch the flame at all.. the inside barrel is turned upside down with the material inside so it is basically loosely sealed against the floor of the  outside barrel.  It is the same system as Peter Hirst uses, but with scrounged barrels.  The heat is travelling around the outside of the container  holding the biomass; forcing the gasses down so they have to pass through the flame to get out of the barrel. Both of them use the fire above and around the material container to force out the volatiles.

What I am suggesting is that you try running the heat from the bottom as per the sawdust stove up the INSIDE of the container  with the biomass. Just don't take out the chimney, basically.  In neither case is the flame directly in contact with the stuff to be charred, in both  the gasses that are expelled by the heat are forced to travel through the flame in order to exit.

I have seen water heaters adapted to this sort of thing, instead of the outside of the tank being heated, a column INSIDE the tank is heated. Does that help with the image?I am not very good with computers or I would try to draw it  
 
Sergio Santoro
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Location: Nicoya, Costa Rica
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I think it's clear now. If I got it right, it goes back to this idea, right?

http://www.youtube.com/watch?v=nQxIXDo-egA&feature=related
 
Sergio Santoro
Posts: 257
Location: Nicoya, Costa Rica
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As far as sealing the drum, how critical is it? Because you may have seen my drum. I can hammer it back in place, but that's about it. As far as using cob, I have the material, but wouldn't it fall off with the heat?
 
                        
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This site  is dedicated to the use of rice husk
http://bioenergylists.org/stovesdoc/Belonio/Belonio_gasifier.pdf  so that might give you some ideas as well.. 

I think you had best try to stick with the system you were trying and see if you can get it to work the way you want; rather than try to do the adaptation of the sawdust stove. If you use the barrel you showed earlier in any  way other than the way you were trying to use it, the cuts in it will allow the offgassing to escape into the air, and you need to be able to force them to go through the fire.

Good luck!

 
Jordan Lowery
pollinator
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Thanks, I'll definitely keep this in mind, but right now we're in the middle of the rainy season here and I couldn't do that. Also, it seems to make a lot of smoke.



does it rain 24/7? it only takes an hour or so, a couple hours for a real big pile. i make rice hull char all the time. around here its illegal to burn anything in the dry season..
 
Sergio Santoro
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Location: Nicoya, Costa Rica
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Not 24/7, but very unpredictably. Also, most likely in the afternoons, which is when I am free, as I cook lunch and do other things in the mornings.

So, I adapted my drum and the result was so-so. To begin with the drum wasn't resting on a support that was tall enough, which jeopardized the air flow a bit. For the most part, as you'll see in the photos, I couldn't quite seal the drum, so all the wood gases would escape. Sometimes they would ignite, but nothing major. Eventually it started to drizzle so I even left. Now the embers at the bottom are cold, but the rice hulls seem to be still charring, not too much smoke. I'll see in the morning. Hopefully I won't find a pile of ash.

How the heck am I supposed to seal that drum now? And even if I buy a second one, how am I supposed to load the rice hulls?
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Sergio Santoro
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Location: Nicoya, Costa Rica
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Two more
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Sergio Santoro
Posts: 257
Location: Nicoya, Costa Rica
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I'm still here, trying to figure out how to keep a drum sealed and load it with rice hulls at the same time. I cut out those flappy parts, so the top and bottom match a little better, still a lot of wood gases escape, but it did work better last time. It still made a heck of a lot of smoke.
 
                                                  
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Here is a historical note - Back in the late 1980's I participated in a historical and archaeological survey of the charcoal pits associated with Hopewell Furnace in southeastern PA. Here's a quick summary of what we found.

Pits, which were really fairly shallow depressions maybe a foot deep at most, were round and about 14 feet across. Many had a few stones piled up in the middle to hold logs into a conical mound. They were constructed with short logs on the inside, increasingly longer logs in layers until the heap looked like a tipi about fifteen feet tall. Most of the logs were about 6" in diameter, from coppiced trees in the natural forest. This was covered over with a layer of mud of indeterminate thickness, probably in the neighborhood of six inches. The fire was set, and once the master collier determined that it was going appropriately, the vent holes were covered up. It could take as long as a week to reduce this pile to charcoal, so the colliers stayed on site in tiny cabins barely big enough to stretch out in. They worked in shifts, because the pit had to be tended 24 hours a day lest a hole develop in the mud covering. If that happened, the whole thing could become a big bonfire.

The product was used by a large charcoal iron furnace that is now a national park. Charcoal iron is exceptionally high quality, and very ductile. It is hard to get and still in high demand for iron applications that require flexibility and durability.
 
                              
Posts: 9
Location: SW Mo working in Kabul Afg
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I have a friend back home that makes his own charcoal for use in his foundry.
There are a few of us in the area who have one man saw mill operations and he would utilize our slabs of scrap. branches and anything else he could get his hands on.
His set up was fairly simple
A 55gal drum with a removable lid. The lid had the 2 bung holes in it. I believe they are a 2.5 and a 1 in plug.
With the lid attached, the 1 in bung on the up side of the drum, a  1n pipe. it would come out of the bung, down and then under the drum. The section under the drum traveled the full length of the drum. This section of pipe had small holes drilled in it aprox every 3 to 4 in ant a off center angle. The drub would be filled with the chunks of green wood, then closed up and set on a brick work. He then built a enclosure around the barrel also with bricks. leaving space in the front to tend the fire that was to be built under the barrel. As the barrel was heated up, the gas would be cooked off and escape out the 1 in pipe and would then be ignited by the fire. It sounded like a jet on afterburner. when the fire coming out of the pipe subsided, the external fire was extinguished and the barrel was left to cool off. Opening the next day revealed about a 30 % loss of mass but none the less a barrel full of usable charcoal.

When I am home next, I will try to get some photos
 
Posts: 103
Location: NW Montana, Hardiness Zone 4b
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After researching biochar for years my business partner and I invested several thousand dollars into developing a portable kiln that could be used alongside fuel-reduction work in the woods around here (Blackfoot/Clearwater/Swan). After looking at the economics of this ancient enterprise and doing our own practical research, we were ambivalent about the wisdom of pursuing the enterprise. Then the USFS announced that they were awarding UM/Forestry and Tri-Con Lumber mill $5.9 million in research funds. That was the end our commercial aspirations regarding biochar.

However, biochar is great for most soils for a number of reasons that I won't go into now - but have been very well and prolifically document. (See International Biochar Initiative.)

Meanwhile, for our edible forest gardens project I used 10 or so cords to create biochar using the most ancient of techniques - the charcoal pit. I tried several pits (10) using variations on the very simple theme found on this website: http://biochar.bioenergylists.org/content/biochar-trench-mounds

The advantage is that we won't need to move the charcoal. We just mixed it into the soil where we made it. It's not as efficient as a retort kiln in the sense that the "highest treatment temperature (HTT) and residence time (important factors) are variable and not controlled. But, the advantage is that we just dug the pits and did it. For now, I'm happy with the results.

Incidentally, for anyone interested in making pine biochar in this area (Blackfoot/Clearwater/Swan), I am interested in buying low-temp product that's reasonably priced.
 
Posts: 125
Location: Gold Coast Hinterland QLD, Australia
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Top Lit UpDraft stove - also know as a 'Hobo Stove'.
I've used these to good effect when camping before - can just break up small sticks, and burns nice hot and clean
 
Mat Smith
Posts: 125
Location: Gold Coast Hinterland QLD, Australia
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Jack Shawburn wrote:Please soak your charcoal before crushing it if it's to be put into the soil as biochar.


I was taught something to that effect also.
I used liquid worm castings to soak mine so that the charcoal was inoculated with all the microbial life.
Come to think of it now, I think I might use some of the runoff water from my mushroom growing as it will help inoculate the charcoal and soil with mycorrhizal fungi!
 
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