Oregon Kiln Making Biochar in the Woods

Well I finally did it. Got some kilns out in the woods to burn slash piles that are normally incinerated to ash. Thanks to Grayback Forestry and Sean Hendrix for inviting us to bring the kilns to see what they could do. Each kiln consumed about 6-8 burn piles and made close to a cubic yard of char. It rained steadily all morning, but we were still able to make char. We lit up at 9 am and quenched at 12:30. I was pleased to see it took less than 50 gallons of water to completely quench one kiln. Took a lunch break and dumped the kilns and loaded them back on the trailer. Went pretty smooth, really.

Some of the Forest Service fire people were there and they said that 7 piles corresponds to about 40 feet of roadside thinning. So if you could unload 20 kilns along 800 feet of roadside, you could treat all the slash and make 20 cubic yards of biochar in 6 hours of work. If the feedstock is well-staged and you don't have to pull apart piles and move it long distances, I think one worker (a young, strong one, not me!) could feed 4 kilns continuously. So a crew of 6 could do it. You'd need a flatbed to transport the kilns and 1000 gal water truck to quench.

The only part I have not figured out yet is how to gather up the biochar for bagging. I'd like to try a shredder vacuum, but I worry about wet char sludge clogging up the works. Otherwise, a loader with a scoop could pack it into totes for sale. You'd get a little forest duff in the bags, but that's a bonus extra!

 

Web album here: https://picasaweb.google.com/113563255252052826854/OregonKilnSlashPiles?authuser=0&feat=directlink

 

 

 

First Firing of the Oregon Kiln

Here's an album of pictures from the first firing of the Oregon Kiln that took place at Willow Witt Ranch on Nov 27, 2015. Thanks to Suzanne and Lanita of Willow Witt Ranch and helper Micah. Thanks also to Vicklund & Son for fabricating the kilns and mounting the jib crane to the trailer. The Oregon Kiln was designed by Kelpie Wilson, Wilson Biochar Associates (wilsonbiochar.com). The Oregon Kiln is a Flame Cap Biochar Kiln intended for use with forest slash and other kinds of waste wood commonly found in the forested regions of Oregon and elsewhere. 

Willow Witt Ranch Char Day Web Album

I was impressed with the efficiency of the kiln. We had some big chunks - 4"x4" and even a little bigger that charred nicely. And it did not take all day. I showed up at 10 am and we lit the rick at about 11 am. Quenched at around 5 pm. So the burn was only 6 hours long. Compare to my 4 foot diameter, 4 foot tall tube kiln that took 11 hours to fill. Total volume is almost the same. The Oregon kiln dimensions are 4' square bottom base, 5' square top base and about 25" elevation (sides are 26" wide).

Here is a simple description of how the kiln works:

You have to think of the Flame Cap Kiln as a retort that is made of steel on the bottom and of a stable gas vortex (actually a collection of vortices) on the top. Both function to exclude air, hold in heat, and char the feedstock.

Next task is to design some better wind screens - I'm thinking of something modular that can be moved around the kiln as needed.

These kilns are being used for a project to help farmers make their own biochar. Read more about that at www.ubetbiochar.blogspot.com

More pictures:

 

Making Biochar in the Snow

Making biochar in the snow. This Flame Cap Kiln is 14 ga (1.9mm) steel and it weighs less than 200 lbs. It's an inverted, truncated pyramid with a bottom base of 122 cm (4 ft), a top base of 152 cm (6 ft) and sides 66 cm (26") high. Capacity is 1.2 cubic meters. Cost $600 to make in Oregon, USA.

Edible Acres Does Backyard Biochar Right

Here is another very simple approach to backyard biochar from Edible Acres. Great job on this and you'll learn a lot of fine points about kiln operation from Sean's commentary. Pay attention to what he says about quenching!

Gary Gilmore's Bolt-Together Pyramid Kiln

Gary Gilmore is our latest contributor to backyardbiochar.net. Thanks Gary for your words and pictures, presented below, and thanks especially for the drawing that will help others fabricate their own versions of this kiln.

There are four pieces made from 1/8” (11 gauge) mild steel.  The top is three feet wide, each piece is two feet high and the bottom is one foot wide.  Each piece is identical and has a flange with bolt holes.  The battery powered drill  gives a sense of scale and facilitates screwing it together.

Pyramid Kiln
by Gary Gilmore

Last year I cut the end off an old tank that was four feet in diameter.  When laid flat the sides extended up about a foot.  A chain was attached to it for the tractor to drag it around to where the brush piles awaited to be made into charcoal.  The process is simple.  Start a fire in the big fire ring and keep adding brush.  As the wood burns, it turns to charcoal which falls to the bottom.  More wood is added over this to prevent oxygen from getting to the hot coals.  After several hours of adding brush, the fire ring is full of charcoal which is extinguished with water.  

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A somewhat similar arrangement is posted on the Green your head website run by Kelpie Wilson of Oregon.  It is called a Japanese cone kiln which is tapered.  This was a better design than the end of an old tank because the sides were sloped.  This helped radiate heat back up and funneled charcoal to the bottom more quickly so it would not burn up.

While thinking about the logistics of cutting and rolling a cone, Kelpie came up with four sided pyramid shaped kiln that gave good results.  The logistics of working flat steel suddenly became easier.  This design was welded together but got me thinking about a slight change to allow it to be bolted together.  With a pyramid kiln that can be bolted together you can easily ship it and disassemble it for storage.  

Here are some photos of my changes to the Wilson pyramid kiln.

The pyramid is assembled upside down.  It took three minutes to put this together.

The pyramid is now right side up and ready to use.  Note the flange on the top of each piece faces into the center of the kiln.  This gives the sides rigitiy and allow the sections to nest.

A closer look at the bolting flanges and the top flange.  There is a possibility this kiln can warp if it gets red hot.  If that were the case, it will be necessary to keep it bolted together.  Howerver, there is a chance this may not happen.  Time will tell.

Here the kiln has been unbolted and each piece nicely nests inside the other.  There are four panels in this picture.  This unit weights 75 pounds.

Open Source It! Layout for the 32" Pyramid Kiln

If you want to buy your own pyramid kiln, you can order one from Blue Sky Biochar on eBay. But these kilns are heavy and hard to ship, so they are only available by local pickup in Thousand Oaks, CA. You can also buy the 32" kiln from me, available by local pickup in Cave Junction, OR. I can also deliver to a few other locations in Southern Oregon and Northern California. Use the email link in the right hand column to inquire if you are interested.

You can also make your own. Just print out the layout sheet below (click on the picture for a bigger version) and take it in to a local welding shop and ask them to make you one. This layout actually makes 2 kilns, so make one for a friend, or use them both! We use 14 guage steel and 1/2" square tubing around the rim for stability. You can get fancy and add handles, a removable BBQ grill, a lid for dry quenching, etc.

Pyramid Kiln Layout. By Kelpie Wilson.

pyramid kiln layout 32 inch by Kelpie Wilson is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Based on a work at www. backyardbiochar.net.
Permissions beyond the scope of this license may be available at www. backyardbiochar.net.

Excellent Engineering Report on Moxham Kiln

If you are interested in designing biochar kilns, I highly recommend this report. You can download it here.

 

 

Biochar-Making Hot Tub

This is really neat. Carbon-negative hot tub. From Edible Acres.

 

Note on Terminology: Flame Cap Kiln is the Winner!

Earlier on this blog, I posted several ideas about terminology for the cone kiln pyrolysis method. I proposed the acronym TFOD - for Top-Fed Open Draft. While this is descriptive of the process of feeding and operating the kiln, it does not really explain the pyrolysis principle utilized. And it is JAUA - Just Another Ugly Acronym. 

So, after some discussion with friends at the Biochar Journal, we have converged on the terminology Flame Cap or Flame Curtain Kiln. I like Flame Cap Kiln because it best describes what I see in my kilns. The flame sits on top of the feedstock like a cap. The cap of flame excludes oxygen while applying heat. 

Charring Woman Biochar Sanitation Idea

Here's an idea (free for anyone to adopt!) for organizing biochar sanitation for a festival like Burning Man:

Charring Woman Biochar Camp

Purpose: To demonstrate ways that Burning Man (or any festival) can turn wood sculptures to biochar using top-lit burning methods and graywater to quench burns and save biochar. Biochar is then used to deodorize and sanitize human waste that can be taken home and used in gardens.

 

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Inspiration: Charring Woman is the Great Goddess of the Soil. She is known as Cybele, Kali, Isis, Oya, Matka, Black Artemis, Black Tara and the Black Virgin. She asks for biochar to renew her fertility. She brings joy to those who recycle their waste to build soil.

Camp Components

• Biochar Pee Buckets – 5 gallon buckets filled with biochar, sawdust and bokashi that are distributed to campers for personal use and transport back to home gardens.
• Biochar Poo Bucket Toilets – a bank of toilets based on the 5 gallon buckets. Contents will be emptied into 55-gallon drums and transported to a humanure composting facility.
• Pyramid Kilns for demonstrating top-lit burn methods that can be used in all burns for maximizing char production. Biochar produced is used in Poo and Pee Buckets.
• Graywater Utilization System – graywater collection tanks that are used to quench Pyramid Kilns. Graywater will mostly vaporize on quenching. What does not vaporize will be re-used.

Camp Activities

1. Distribute Biochar Pee Buckets and educate about their use

Charring Woman will prepare thousands of 5 gallon buckets with a mixture of biochar, sawdust and bokashi (a lactic acid inoculant that ferments urine, preserving nitrogen and drastically reducing odor). We will also disseminate information about how to use the buckets and how to add the contents to garden soil for increased fertility. The goal is to eventually have every camper collect and transport all of their urine back home in biochar pee buckets.

2. Provide Biochar Poo Bucket toilets and educate about their use

Charring Woman will construct a small bank of biochar toilets using 5 gallon buckets – about 20 toilets. We will produce information on the proper use of the toilets. Volunteers will empty the buckets into 55 gallon drums that will be hauled offsite for composting with a humanure composting system using straw and other bulking materials. The goal will be to gradually transition the entire festival from chemical toilets to the Biochar Poo Bucket/Humanure Composting System over several years.

Biochar Poo and Pee Buckets at home. Open Poo Bucket shows how the combination of biochar and bokashi ferments and stabilizes poo and kitchen waste, producing a kind of “Poo Cheese.”

3. Pyramid Kiln demonstrations

The Pyramid Kiln is a brazier that serves as a container for top lit debris fires. Using wood debris or small sculptures, we will demonstrate the top lit method of burning that minimizes smoke and maximizes char production.

The Pyramid Kiln in action. It can produce biochar while disposing of MOOP (Material Out Of Place). Once the initial stack has burned down to hot coals, add additional material one or two layers at a time until the kiln is full, and then quench with water.

4. Graywater beneficial use

Charring Woman will establish a graywater collection system to use for quenching the Pyramid Kilns and biochar stoves. Water quenching is essential for saving the biochar. It will also help dispose of graywater as much of it will vaporize during quenching.

References

Learning to Burn and Make Biochar, Not Smoke. Kelpie Wilson. Tree Care Industry Magazine. February 2014.

Kelpie Wilson Keynote Presentation: The 19th Century Roots of Modern Biochar, 2013 US Biochar Symposium, Amherst, MA, Oct. 13-16

Terra Preta Sanitation Initiative, Hamburg University of Technology, http://www.terra-preta-sanitation.net/cms/index.php

Terra Preta Sanitation Video

Here is a wonderful video from Valentina Karga and friends showing a public toilet they created in a public park using the Terra Preta Sanitation principles:

Temple of Holy Shit for the Blue Responsibility Award from Valentina Karga on Vimeo.

Humanure Festival System Video. A good example of how to set up a whole system. Could be slightly improved by adding some bokashi and biochar.

First Firing of the Flame Cap Tube Kiln

I finally got to fire up the tube kiln - it is 4ft diameter and 4 ft tall. I made a heat shield out of some thin, finely corrugated steel from an above ground swimming pool - got it at a yard sale for $5!

Here is a slide show video:

The heat shield makes a big difference. It's all about holding as much heat in the flame zone as you can. You can see from the pictures that there is not much smoke emissions. The cap of flame on top burns the smoke for clean operation.

We actually tried 3 different methods at once - Tube Kiln, Pyramid Kiln and TLUD - a Three Ring Circus of Pyrolysis! 

The Forests Are Lonely

On Saturday, I visited Edgewalkers Social Forestry Wintercamp, located this season in the mountains outside of Ashland, Oregon.  This group of nomadic forest restoration workers is learning about forest restoration and fire ecology in oak woodlands through sharing knowledge and skills and also through sitting in quiet observation of the processes and creatures around them. They have been at the camp for four weeks now, and are beginning to apply their learning - cutting and burning small firs and brush that crowd the old oaks and compete with them for water and nutrients. These forests are adapted to a natural fire interval of a few decades, where wildfire used to clear out the understory on a regular basis, without damaging the big, old trees. A century of aggressive fire suppression has left the forests thick with small fuels that set the stage for conflagration - the explosive wildfires that have raged in the western forests of the US at an ever-increasing rate.

The Edgewalkers Forestry Camp - with their new Pyramid Kiln

The Edgewalkers have big ambitions. They want to not only learn skills and apply them to a piece of land, they also want to create new life paths for humans in relation to forests. Read more about them on their Indiegogo page.  There is an upcoming opportunity to learn more about social forestry at the Social Forestry Advanced Permaculture Course with Tom Ward, February 2-7, 2015. Here's a description of the concept: "Social Forestry connects villages and communities to their forested water catchment basin. Here in a developed industrial empire, the forests are lonely. We have lost our sense of living with forests as friends."

I brought the Edgewalkers a Pyramid Kiln so they can make biochar during their evening campfires - Social Biochar! I hope they will use to also bake potatoes and grill food. I enjoyed meeting these dedicated forest workers. We talked about fire and the best ways to reintroduce it to the forests, as well as techniques for top lit fires that reduce smoke and leave behind biochar. Wet wood is the biggest challenge. Wet wood makes it difficult to build up a good bed of coals in the Pyramid Kiln, but once there is a layer of hot coals, the wet wood is more managable because there is enough heat to dry it. 

Using a small Top-Lit Open Burn stack to start the Kiln. Notice we used a bit of dry firewood to get it started. This is really important when you only have wet wood to add. The dry stuff will give you a good quantity of hot char-coals to get started with. 

When wood is wet, small diameter twigs won't char easily - they tend to go straight to ash. The challenge is to get enough heat in the bed of coals to dry and char larger sticks, so the char can build up.