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Difference between revisions of "Charcoal production"

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(Created page with "This article deals about the making of charcoal. ==Methods== A clamp for charcoal production Charcoal has been made by various meth...")
 
(External links: Added external link)
 
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This article deals about the making of charcoal.
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This article deals about the '''production of charcoal'''. There are several methods for processing wood residues to make them cleaner and easier to use as well as easier to transport.  Production of charcoal is the most common. 
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It is worth mentioning at this point that the conversion of woodfuel to charcoal does not increase the energy content of the fuel - in fact the energy content is decreased.  Charcoal is often produced in rural areas and transported for use in urban areas.  
  
==Methods==
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==Overview==
[[File:Charcoal clamp.JPG|thumb|right|150px|A clamp for charcoal production]]
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The pyrolysis temperature appears to be a critical factor determining char yield vs. energy yield (tradeoff). Flexi-pyrolysis units are being developed that can be set for either char yield or gasification yield. Dry biomass can be pyrolyzed at regular atmospheric pressure. For wet biomass, pyrolysis at higher pressure ("supercritical") may be necessary, requiring a more sophisticated technical set-up.
Charcoal has been made by various methods. The traditional method in Britain used a clamp. This is essentially a pile of wooden logs (e.g. seasoned oak) leaning against a chimney (logs are placed in a circle). The chimney consists of 4 wooden stakes held up by some rope. The logs are completely covered with soil & straw allowing no air to enter. It has to be lit by introducing some burning fuel into the chimney; the logs burn very slowly (cold fire) and transform into charcoal in a period of 5 days burning. If the soil covering gets torn (cracked) due to the fire, additional soil is placed on the cracks. Once the burn is complete, the chimney is plugged to prevent air to enter.[3]
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When large chunks of wood are used as feedstock, the charcoal may need to be crushed before use (beware: coal dust explosion !). Many agrigultural feedstocks and leaf litter will not need to be pulverized but will readily break into smaller pieces by themselves. For information on small-scale gardening, please consult the [http://biochar.pbwiki.com/ Gardening with Biochar FAQ], an excellent resource.
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==Kilns used==
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Charcoal can be made using various types of kilns.
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==Using traditional kilns==
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[[Image:Biomass3.jpg|thumb|200px|right|Image 1: Traditional Earth Kiln for Charcoal Production]]
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[[Image:Biomass4.jpg|thumb|200px|right|Image 2: Charcoal Kiln, Kenya ©Heinz Muller/Practical Action]]
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[[Image:Biomass5.jpg|thumb|200px|right|Image 3 Improved Charcoal Kiln Found in Brazil, Sudan and Malawi]]
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The process can be described by considering the combustion process discussed above. The wood is heated in the absence of sufficient oxygen which means that full combustion does not occur. This allows pyrolysis to take place, driving off the volatile gases and leaving the carbon or charcoal remaining.  The removal of the moisture means that the charcoal has a much higher specific energy content than wood.  Other biomass residues such as millet stems or corncobs can also be converted to charcoal.
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Charcoal is produced in a kiln or pit. A typical traditional earth kiln (see image 1) will comprise the fuel to be carbonised, which is stacked in a pile and covered with a layer of leaves and earth.  Once the combustion process is underway the kiln is sealed, and then only once process is complete and cooling has taken place can the charcoal be removed.
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A simple improvement to the traditional kiln is also shown in image 3. A chimney and air ducts have been introduced which allow for a sophisticated gas and heat circulation system and with very little capital investment a significant increase in yield is achieved.  
 +
 
 +
==Using a clamp==
 +
The traditional method in Britain used a clamp which is itself already a relatively advanced yet locally-constructable kiln. This is essentially a pile of wooden logs (e.g. seasoned oak) leaning against a chimney (logs are placed in a circle). The chimney consists of 4 wooden stakes held up by some rope. The logs are completely covered with soil & straw allowing no air to enter. It has to be lit by introducing some burning fuel into the chimney; the logs burn very slowly (cold fire) and transform into charcoal in a period of 5 days burning. If the soil covering gets torn (cracked) due to the fire, additional soil is placed on the cracks. Once the burn is complete, the chimney is plugged to prevent air to enter.[3]
 
Modern methods use a sealed metal container, as this does not have to be watched lest fire break through the covering.
 
Modern methods use a sealed metal container, as this does not have to be watched lest fire break through the covering.
  
==Why==
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==Using charcoal kilns==
calorific value is higher (heat per weight). This means that a higher temperature can be acheived; also if the fuel is not burnt where it is grown, the trnasport cost is lower. Peterkingiron (talk) 17:17, 18 December 2010 (UTC)
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[[File:Charcoal_kiln.png|thumb|right|200px|DIY charcoal kiln made from oil drum]]
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Several (relatively inexpensive) charcoal kilns can be made which can be used to make charcoal/ See [http://www.biochar-international.org/technology/production the designs at Biochar-international page 1] and [http://www.biochar-international.org/technology/stoves page 2] Most of these require at least some parts which can not be found in a natural environment (ie metal parts). On the upside however, such parts typically last longer and may be more efficient. Some very simple designs also exist consisting of only a few metal parts (ie 2 barrels), see [http://www.nasa.gov/topics/nasalife/features/biochar.html NASA Langley Research Center's low-tech kiln]
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==See also==
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* [[Wood]]
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* [[Charcoal]]/[[Biochar]]
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* [[Charcoal Making for Small Scale Enterprises]]
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* [[Blackpowder]]
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==External links==
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* http://en.wikipedia.org/wiki/Charcoal
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* http://www.velvitoil.com/Charmake.htm
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* http://www.wikihow.com/Make-Charcoal
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* http://www.instructables.com/id/How-to-Make-some-Charcoal/
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* [http://vignette3.wikia.nocookie.net/solarcooking/images/e/ef/Traditional_Charcoal_in_Africa_and_need_of_African_Institutes_ARTIS.pdf Traditional Charcoal in Africa and need of African Institutes]
  
 
[[Category:Charcoal]]
 
[[Category:Charcoal]]
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[[Category:Energy storage]]

Latest revision as of 13:39, 2 July 2016

This article deals about the production of charcoal. There are several methods for processing wood residues to make them cleaner and easier to use as well as easier to transport. Production of charcoal is the most common.

It is worth mentioning at this point that the conversion of woodfuel to charcoal does not increase the energy content of the fuel - in fact the energy content is decreased. Charcoal is often produced in rural areas and transported for use in urban areas.

Overview[edit]

The pyrolysis temperature appears to be a critical factor determining char yield vs. energy yield (tradeoff). Flexi-pyrolysis units are being developed that can be set for either char yield or gasification yield. Dry biomass can be pyrolyzed at regular atmospheric pressure. For wet biomass, pyrolysis at higher pressure ("supercritical") may be necessary, requiring a more sophisticated technical set-up.

When large chunks of wood are used as feedstock, the charcoal may need to be crushed before use (beware: coal dust explosion !). Many agrigultural feedstocks and leaf litter will not need to be pulverized but will readily break into smaller pieces by themselves. For information on small-scale gardening, please consult the Gardening with Biochar FAQ, an excellent resource.

Kilns used[edit]

Charcoal can be made using various types of kilns.

Using traditional kilns[edit]

Image 1: Traditional Earth Kiln for Charcoal Production
Image 2: Charcoal Kiln, Kenya ©Heinz Muller/Practical Action
Image 3 Improved Charcoal Kiln Found in Brazil, Sudan and Malawi

The process can be described by considering the combustion process discussed above. The wood is heated in the absence of sufficient oxygen which means that full combustion does not occur. This allows pyrolysis to take place, driving off the volatile gases and leaving the carbon or charcoal remaining. The removal of the moisture means that the charcoal has a much higher specific energy content than wood. Other biomass residues such as millet stems or corncobs can also be converted to charcoal.

Charcoal is produced in a kiln or pit. A typical traditional earth kiln (see image 1) will comprise the fuel to be carbonised, which is stacked in a pile and covered with a layer of leaves and earth. Once the combustion process is underway the kiln is sealed, and then only once process is complete and cooling has taken place can the charcoal be removed.

A simple improvement to the traditional kiln is also shown in image 3. A chimney and air ducts have been introduced which allow for a sophisticated gas and heat circulation system and with very little capital investment a significant increase in yield is achieved.

Using a clamp[edit]

The traditional method in Britain used a clamp which is itself already a relatively advanced yet locally-constructable kiln. This is essentially a pile of wooden logs (e.g. seasoned oak) leaning against a chimney (logs are placed in a circle). The chimney consists of 4 wooden stakes held up by some rope. The logs are completely covered with soil & straw allowing no air to enter. It has to be lit by introducing some burning fuel into the chimney; the logs burn very slowly (cold fire) and transform into charcoal in a period of 5 days burning. If the soil covering gets torn (cracked) due to the fire, additional soil is placed on the cracks. Once the burn is complete, the chimney is plugged to prevent air to enter.[3] Modern methods use a sealed metal container, as this does not have to be watched lest fire break through the covering.

Using charcoal kilns[edit]

DIY charcoal kiln made from oil drum

Several (relatively inexpensive) charcoal kilns can be made which can be used to make charcoal/ See the designs at Biochar-international page 1 and page 2 Most of these require at least some parts which can not be found in a natural environment (ie metal parts). On the upside however, such parts typically last longer and may be more efficient. Some very simple designs also exist consisting of only a few metal parts (ie 2 barrels), see NASA Langley Research Center's low-tech kiln

See also[edit]

External links[edit]