was traditionally and is Charcoal kilns produced in so-called. This is to char the material - usually wood, there may be other plant materials are used - piled on the ground floor in a heap, where they can be in the middle of a vertical opening. The pile is then covered with straw and then ground. (See illustration)
Now the interior of the pile is ignited by giving some red-hot charcoal into the vertical opening and closes it. The wood starts to smolder, ie, it decomposes in the heat, and it gives off flammable gases. Since the covering can penetrate a little air, the fire goes out and not in the course of several days - depending on the size of the pile - the entire carbonized material. What is left is charcoal, which is about one-third to more than half of its weight of the original wood.
This method is practically used in industrial countries, only to preserve tradition. In the developing and emerging countries, it is still a daily practice, since there charcoal used for many purposes, but is mainly used for cooking. This type of charcoal production, however, has at least one serious disadvantage: not very well controlled charring of the biomass is very free of noxious gases. There are Large amounts of dust, harmful fumes that can lead to sometimes fatal respiratory disease, but also the gas methane, which has over Kohldioxid (CO2) is 23 times stronger greenhouse effect. Moreover, the energy that is released in this process, wasted.
So if you think about it, to win charcoal in large quantities, such as the manufacture of terra preta, separates the kiln process in principle. Is needed are techniques that avoid the release of pollutants and may allow more energy use. Here are three different methods are used, one with even relatively little effort can be implemented: first
Cooking stoves, which allow secondary air to an incomplete combustion.
second Technical pyrolysis
third Hydrothermal carbonization.
In this article we restrict ourselves to the first procedure and the other two describe in the next few articles.
As mentioned above, are cooked in large parts of the world with wood or charcoal. This happens very often on simple fire places, which have only a low efficiency, ie, much of the heat that they actually intended to use for cooking is lost due to inadequate fire pits. In the simplest Case, these are a few stones, which is placed around a small basin, and where the pot is turned off. is simple, built of clay "ovens" are the next level, but are still very inefficient. This will also mean that is used to prepare the necessary hot meals a lot more wood or charcoal, as is actually necessary. Kocher, who work with petroleum, constitute no alternative, because this part of the global population of this fuel is much too expensive, aside from the petroleum than fossil fuel in the long run anyway can not be a solution, because its combustion to global warming.
In recent times, therefore, many efforts have been made to develop suitable ovens with which one can extract out of cooking and charcoal, both in the developing countries themselves, as well as engineers in developed countries. With the variety of different types, one could already fill a book, so we will restrict ourselves only to a model. The illustrated furnace is Anila-Stove and is mainly used in Asia
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