Everything I know about Making Charcoal and Biochar

[onesojourner]

Part 1: Why

Fuel
There are many, many reasons to make charcoal and biochar. My number one priority is to make a high quality cooking fuel. Cooking a hot meal is something that most people do every day. If there is any kind of short term or long term disaster cooking fuel could be in short supply very quickly. I have a charcoal smoker/grill and charcoal is expensive. I suspect I will be able to recoup all costs of building a retort in one or two batches of charcoal. The majority of my extended family also have charcoal grills so not only will this save my immediate family money but I will also be able to save my extended family money. If there is any kind of disaster we will all be able to have a hot meal.  Another use for charcoal is a fuel source for a forge. It may not get as hot as real coal but it should be acceptable.

Biochar
My other main reason for building a retort is to make biochar. I won’t go into details just yet but charged, crushed up charcoal or charred biomass is an incredible soil amendment that I want to take advantage of. Instead of burning weeds, Leaves and sticks all this could be put in a forge and turned into black gold. Gabriel Hemery has a nice little article that further explains biochar. http://gabrielhemery.com/2011/12/12/biochar-explained/

Water Filtering
Charcoal has an enormous surface area. This is why there are so many water filters and the market that are based on charcoal filters, including Berkey Filters. I won’t don’t know much about using charcoal as a filter but I have seen it done and I do believe I can keep my family from getting sick from drinking dirty water.

Activated Charcoal
I won’t pretend to know much about this. Provided you have “cooked” your charcoal sufficiently you will have nearly pure carbon that you can use for all kinds of alignments. 
http://en.wikipedia.org/wiki/Activated_carbon

Biochar vs Charcoal

[archer]

I'm interested. please continue.

[backwoods_engineer]

[onesojourner]

Part 2: The Direct Method

Traditional charcoal was made using the direct method. Wood was piled up and lit. Once it was burning cleanly (or sometimes not) the fire was smothered with Soil or doused with water. This resulted in mediocre charcoal. It is almost impossible to have nearly pure carbon with this method. Some pieces of wood are going have most of the gases driven off and others will be blackened wood. Using this to cook with will give you inconsistent results. It will be smoky and burn times and temperatures will vary. A modern example of this would be THIS. Notice how much smoke there is in the video. This is all wasted energy that could be turned into heat to drive off more of the gasses. If you decide to go this route it is cheap and easy but it will make for some very unhappy neighbors. We can obviously do better than this and use our resources more responsibly.

[ID_Joker]

 

[Dainty]

I've been fascinated by this subject for a while. Great info, thanks.

[onesojourner]

Part 3: The indirect Method

Making charcoal with the indirect method is slightly more complicated but the potential efficiency and the quality of the final product make it well worth the effort. To make charcoal indirectly you have fuel wood separate from the biomass you want to turn into charcoal. The biomass will be in a nearly air tight container, this is known as pyrolysis. When you heat the biomass container up the biomass is going to begin giving off gas. This gas has a large amount of energy still in it, you may have heard it referred to as wood gas or sengas. This is the same stuff you can run an internal combustion engine on. A simple example of this would be to light a fire under a 55 gallon barrel and set the lid on top. When the pressure builds up from the gas it will vent out the top. This will yield very high quality charcoal but you are going to have to burn up a lot of wood to do it and it is going to be a smoky mess. Make sure you are down wind from your neighbors. To improve upon this simple design you would need to add a wood stove gasket to the lid so that it seals tight. Drill a hole in the lid and run a gas pipe down to the bottom of the barrel. Hot wood gas wants to go up, but with the pressure that it builds, you can force it to go down, as long as it has no other option. Here is an example:

This design is alright if you are going to have a bonfire, or you are someone just needs to clear some brush and there is going to be a big fire one way or the other. You might as well throw one of these in there and get some charcoal out of the deal.

[soupbone]

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[Aunt]