Whirly Girl Stove Development

I brought the Whirly Girl stove to the Biochar School last month and it was a real hit. Several folks are now working with me on developing this design for some new applications. The swirling flame keeps the heat in the combustion zone longer, making a cleaner burn. Here's an old video showing the stove in action at a permaculture skill share in southern Oregon and at the Tierra Learning Center lodge near Leavenworth, Washington. The Whirly Girl stove is a Top Lit Up-Draft (TLUD) gasifier that makes biochar as it cooks.

Biochar in the Hawaiian Luau Pit

Josiah Hunt has been doing commericial biochar longer than just about anyone. He is perhaps the finest example we have of small scale, low tech biochar entrepreneurship. Being in Hawaii helps - he has abundant feedstock, abundant need (poor tropical soils subject to leaching rainfall) and an educated public of permacultural farmers who get it. But despite the advantages of location, it was Josiah's genius that drove him to invent an economically sound biochar production method that allowed him to actually start a business. Not only that, his method is pretty clean, unlike traditional charcoal pits that smolder wood for many days and emit methane and carbon monoxide. In the open pit method, these gases are burned off so there is very little smoke.

Josiah's pit is a TFOD. No metal cone required. His method of gradually adding new wood over glowing coals is exactly the same method as the cone kiln and qualifies this method as a TFOD. One difference is, he quenches with dirt instead of with water. Here is the link to his description of the method, with pictures:

http://hawaiibiochar.com/biochar-burn-demonstration/

He has since moved on to better, even cleaner biochar production methods, but for those just getting started, you might want to consider the pit. I have no doubt that the method was inspired by the traditional Hawaiian cooking method - the Luau Pit.

Josiah - thank you for sharing!

Moxham Kiln from Charmaster Dolph Cooke is a Flame Cap Kiln

Charmaster Dolph Cooke, from the lush forests of Northern New South Wales, Australia, is a leader in the open source biochar tech movement. I love his latest kiln, inspired by his amazing mentor, Geoff Moxham. Geoff died tragically in a woods accident a few years ago, so let that be a reminder to us all to keep safety first in mind, especially when dealing with big, hot kilns like this one.

You can still glean some of Geoff's wisdom at his website, Bodger's Hovel.

Dolph calls this big tube a Moxham Kiln, so that is how it shall be known. The Moxham kiln inspired me to come up with the nomenclature, TFOD (Top Fed Open Draft) to cover all devices that use this open burning method: cone kilns, pyramid kilns, open pit kilns and the Moxham kiln. This new class of kilns is ultra simple and amazingly clean and smoke free if operated correctly.

Here is a nice video that Dolph made on the Moxham Kiln, where he gives some tips on how to operate it:

Giant Cone Kiln in Illinois

Kamal Rashid, CEO at Zanjabil Gardens in Pembroke Township, Illinois, has made a giant cone kiln. Last month he completed his first full test burn in the kiln, which has a 59" top diameter, a 24" bottom diameter, and is 24" high. The kiln made 133 gallons of biochar (17.7 cu ft) in about 4 hours, using cordwood. Kamal reports that it took 30 gallons of water to quench the kiln. Kamal is also an officer of the Pembroke Farming Family Association, and he helps with technical assistance to other farmers. Kamal is very happy with the cone kiln, which was fabricated by a local community college welding class. You can bet he will be helping other small farmers in his area get started with making and using biochar. Here are some of his pictures: DSC_0120DSC_0111 DSC_0115 DSC_0123 DSC_0126

Idea for Making Wood Vinegar in a Cone Kiln

I found this on a website somewhere - but forgot to copy the url. It is from Poland, I think. This set up is for capturing condensates from pyrolized wood. The condensates range from wood vinegar (pyroligneous acid) to bio-oil - an acid kind of crude oil. There is a lot of information I will post soon about using wood vinegar in farming. Here is what looks like a pretty simple method of making it:

This would be easy to do in a bottomless cone kiln. Just dig a hole under the kiln and set your two containers in the bottom of the kiln. Make sure the retort extends up into the cone kiln so it gets plenty of heat. I will be trying this soon and I'll let you know how it works.

Backyard Biochar Featured in Acres Magazine

Author Daniel Blaustein-Rejto did a pretty nice job on an article on farm scale biochar for Acres magazine. It's in the October 2014 issue: "Playing With Fire - Creating, Using Biochar for Improved Soil." Many of the pictures in the article are from technologies featured on this website. So thanks everyone, for contributing your pictures and stories. More and more people are learning about these small scale, clean biochar technologies, and using them to improve their soils.

Flame Cap Kiln Char Analysis

Biochar researcher John McDonald-Wharry put out a call for char samples a few months ago. I was curious about my cone kiln char, so I shipped a small bit of char out to New Zealand, and John ran it through his Raman Spectroscopy analyzer (see how casually I mentioned that, as if I know what the heck that is!). Here is the note he sent me today, with the results of his analysis:

Kia ora,

I have attached the provisional Raman results for the char sample you sent in. I am in the process of writing a paper on the around 40 samples which were contributed to this Raman survey.

Your sample was well-carbonised in the top 3 of 40 in terms of our measurements of nanostructural development with results similar to our laboratory produced chars at HTTs between 700 and 1000 degrees C. I am impressed with how consistently well-carbonised this sample was with the results indicating a low level of variability with the sample.

I will send out copies of the paper manuscript once it is near completion to the contributors which should help with interpreting results and allow comparisons with a wide range of other chars (and a few other carbonaceous materials).

Thanks,

John McDonald-Wharry

 

This result is very interesting to me. I don't own any thermocouples, so my only way of measuring the temperature of my cone kiln was to use a cheap infrared thermometer on the side of the kiln. I knew it must be hotter than the 350 degrees C I could measure on the outside metal of the kiln, but I had no idea it could get up to between 700 and 1000 degrees C! Time to get some thermocouples and check it out. 

 

The other surprise is what John said about consistency in the sample. I took the sample - just a few grams - from a barrel of char that was made in the pyramid kiln. The char had gone through the leaf shredder, so it was pretty well mixed. Maybe it was just luck, but I am surprised that it was so uniform.

 

Anyway, here are the results that John sent me: Download Raman Report August2014 (Cone kiln)

You are welcome to check them out.

 

And here is what Wikipedia says about Raman spectroscopy:

 

Raman spectroscopy (/ˈrɑːmən/; named after Sir C. V. Raman) is a spectroscopic technique used to observe vibrational, rotational, and other low-frequency modes in a system.^[1] It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range. The laser light interacts with molecular vibrations, phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the vibrational modes in the system. Infrared spectroscopy yields similar, but complementary, information.

Kon Tiki Kiln - Real Wow Power!

Hans-Peter Schmidt and Paul Taylor have invented a new version of the cone kiln they call the Kon-Tiki Kiln. Here's a picture:

The tap at the bottom is for draining the quenching water.

Here are some specs from Hans-Peter:

Kon-Tiki I
volume: 850 liters
Production capacity: 700 l biochar in 4 to 5 hours
yield: 25 to 30% (Dry Matter)

Here is the kiln in operation. He uses prunings and waste from his vineyard:

Lots more information in this great video:

 

Summertime and the Charring is EZ

Larry Peceniak has caught the cone kiln bug and has made several versions out of lightweight sheet steel:

I used 2’x3’  30 gauge galvanized steel for duct work from Home Depot.  The metal is pretty flimsy, but it gets the job done. 

Looks like he uses pop rivets to hold it together. We'll have to get a report from him later on how long this lightweight materal lasts, but for now he's having a great time. He says:

The first char with the new kiln was outstanding.  I charred 15 gallons of split 2x10 pine from a home construction site in about 2 hours while sitting on my patio enjoying the fire! The cone kiln I can actually set in a patio fire pit that I bought and it works great.  Now I can sit on my patio, do a char, and enjoy the fire while I’m just sitting with my wife enjoying a glass of wine.

Here are the pictures:

 

 

 

 

 

 

 

 

Low Tech: Good - No Tech: Even Better

Metal cone kilns are very nice and easy to use, but where steel and welding skills are hard to come by, this simple pit kiln should do the job. This is another design from Hans-Peter Schmidt in Switzerland: