Monday, October 15, 2007

Buffalo and Industrial Biochar

I got to take a long weekend attending a wedding party in Edmonton for a niece. Good times by all. I chatted up a couple of my favorite subjects and picked up a few tidbits and clarified an idea or two.

The first is that buffalo herds are becoming very visible in Northern Alberta. this suggests that the critical mass exists for a huge herd expansion. More importantly, if they were not economic and easy to ranch, this would not be happening. I am told that they are commonly mixed with beef and have obviously become very fence trained. This was the big concern at the very beginning.

What this tells me is that buffalo have been completely accepted into our animal husbandry culture and that there are plenty of farmers moving into the business. We will all live to see millions of animals from the current 500,000 stock. I also know that a number of plains Indian reservations are actively building herds. There is a certain irony in having the descendants of those icons of the great plains take a leading role in buffalo husbandry.

I also got to talking about biochar and terra preta.. I realized that my hesitancy over using a small ten to twenty ton shipping container as a biochar kiln on the farm is misplaced.

A smaller metal kiln would need a daily charge of 10 to 20 tons of plant waste. If the plant waste is corn stover or bagasse, we are processing one hectare's waste on a daily basis. This should, with normal crop management, draw from a one mile radius which is very typical of the large modern farm. This could be operated on a continuous basis throughout the year.

It would be necessary to store the waste in a convenient form next to the kiln and it would be necessary to also store the biochar product until the time for putting it back into the soil. Once the waste is harvested though, the actual production process could be made into a simple daily chore with a little equipment or even just a large front end shovel.

The oven itself (you may wish to review my earlier postings on shipping container incinerator design) been of two lung design will not leak and all the volatiles driven off go directly back into the heat production cycle. It may be possible at some added expense to capture a part of the volatiles as a byproduct.

Because the container is a sealed device, the packing ratio is not nearly so critical as in the earthen kiln design needed by pre-industrial farmers. In fact it would be convenient to chop the stover as is done anyway, and then to blow the material into wagons and holding bins from which it can be then blown into the kiln. There is a good chance that fairly simple modification of existing equipment will solve the technical problems.

Any such dedicated system is also ideal for disposing of unwanted straw bales and any other agricultural waste.

The important concern, is that we are now describing a system that can be made as automatic as your washer dryer and as time saving. The actual burn process itself is easily monitored and controlled with a little in the way of electrical control systems. It should no longer matter even if you are burning a partial load, as long as the space itself is filled to prevent too many hot spots of full combustion.

The capital cost of such a system is potentially very low with the nasty wild card been the very high temperature bricks needed for the small second lung. The rest can be assembled by any backyard mechanic once the design is tested and shaken out.





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