Charcoal and household energy

Table of Contents
What is charcoal? The uses of charcoal Advantages and Disadvantages Making Charcoal Devices Making Charcoal Briquettes Related topics External links and references Contributors

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[top] [end]What is charcoal?

[top] [end]Definition

Charcoal is a processed biomass that can be burned for heat energy. Charcoal means the black solid remaining after carbonisation or pyrolysis of organic matter. Various resources are used to produce charcoal such as wood, agricultural and forest residues, Municipal Solid Waste, fossils matter like peat. In Carbonization processes part of organic matter or solid biomass is burnt to provide the necessary heat. During this processes where solid biomass is heated in the absence of air, the great part of the volatiles are removed. Other resources than wood used for charcoal production require pre-treatment like briquetting or drying and moulding before being charred. This kind of non forest wood charcoal is generally produced in order to substitute it. It is noted that briquettes converted to charcoal know a real success in Thailand, Sudan and Malaysia. Despite the effort done to introduce char briquette as an alternative to the production of wood charcoal from ligneous formation remains more important.

[top] [end]Charcoal characteristics

The table below presents the characteristics of various charcoals and raw wood. Calorific value, density, Volatile matter content other than water, fixed carbon, ash content, and burning time represents the key elements used to appreciate the different type of charcoals.

	Calorific value (Kcal/Kg)	Density	Volatile matter (%)	Fixed carbon (%)	Ash content (%)	Burning time (%)	Reference (%)
Charcoal from wood	7400 - 8000	0.23 – 0.73	17.7 – 19.1	77.6 – 79.5	2.7 – 3.6	30 - 45	3, 5, 6, 7, 8
Charcoal from fossil wood	7300	0.6	18.8	76.5	4.65		4
Charcoal briquette from bagasse	8691	0.8	32.46		16	60 - 75	1
Charcoal briquette from crop residues	7500 - 7800	1.4	7		5 - 7	60 - 90	2, 3
Char peat	4780	1	5.6	45.9	48.5		4
Raw Wood	4000 - 5000	0.31 – 0.88	75 – 80	18 – 24	1.6 – 4.6		5, 6, 7, 8

Wood charcoal seems more interesting owing to its lightest weight, to its lower ash content and the fact that it has higher energy content per unit weight and the greatest percentage of fixed carbon. Char briquette with their highest calorific value and burning time can be a good alternative fuel to substitute wood charcoal. Char peat may show comparable effect with standard raw wood. The fact that chars peat is more smokeless than wood, means that it will be a valuable alternative fuel to firewood. Concerning green houses gas emission, in the range of household fuels used, charcoal releases more than LPG, biogas, kerosene, woodfuel and crop residues.

Table 2: Emissions in g/MJ delivered energy for seven fuels

Fuel	Overall Stove Efficiency (%)	CO2	CO	Methane	TNMOC	N2O
LP Gas	53.6	126	0.61	neg	0.19	0.002
Biogas	57.4	144	0.19	0.10	0.06	0.002
Kerosene	49.5	138	1.9	0.03	0.79	0.002
Woodfuel	22.8	305	11.4	1.47	3.13	0.018
Crop residues	14.6	565	36.1	4.13	8.99	0.028
Charcoal	14.1	710	64.0	2.37	5.6	0.018
Dung cake	10.0	876	38.9	7.3	21.8	0.022

[top] [end]The uses of charcoal

Patterns of wood charcoal consumption are site-specific, i.e. they vary from country to country, and from area to area within countries. They are dependant on the type of area (e.g. rural or urban), availability of local resources and alternative fuels (LPG, kerosene), climate, and they can vary by season. Still, some general observations can be made. In countries which have a long tradition of using wood charcoal as fuel:

Household sector is the greatest consumer. Restaurant and the handcraft sector come in second position with low percent. The use of charcoal in industrial sector is not significant.
Cooking is the main purpose for consuming wood charcoal. Ironing, water heating and conditioning is satisfied exclusively by charcoal.
Most of charcoal produced from ligneous formation are consumed by urban household
Charcoal production and distribution contribute significantly to the Nation’s economy and employment.

[top] [end]Advantages and Disadvantages

The advantages of wood charcoal	The disadvantages of wood charcoal
Charcoal meets a number of requirements concerning safety. This aspect is one of the reasons why charcoal is favoured more than LPG	Charcoal is not a clean fuel
Charcoal burns with a small flame and with less smoke	Charcoal transport and storage can be affected by the loss of weight
Charcoal is easier to handle than wood	Its delay to start burning is longer than other household fuel such as LPG, Kerosene and gelfuel
	It generates more ash than LPG, Kerosene and gelfuel

[top] [end]Making Charcoal

[top] [end]Type of carbonization technology

The earth mounds kiln represents the technique of carbonization widely used in many countries. The production of one tonne of wood charcoal required between 7 to 10 tonnes of raw wood. In Senegal where urban household rely mainly to charcoal to meet their need of cooking, the improved earth mounds kiln is well-known the Casamance Kiln.

The different types of earth mounds kiln

[top] [end]The different steps of production wood charcoal

harvesting wood
felling and bucking to required length
drying of firewood
carbonization

[top] [end]The different steps of carbonization with casamance improved kiln

[top] [end]Devices

[top] [end]Making charcoal

Traditional charcoal kiln

[top] [end]Making Charcoal Briquettes

Making Charcoal Briquettes in China

[top] [end]Using charcoal

Photo of thai bucket charcoal burning stove

[top] [end]Related topics

[top] [end]External links and references

http://en.wikipedia.org/wiki/Charcoal

http://www.worldenergy.org/wec-geis/publications/reports/ser/wood/wood.asp

[top] [end]Contributors

User:Grant Ballard-Tremeer 1 September 2003

Categories: Fuels| Charcoal

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Page created: 01 September 2003; Last edited: 31 March 2008; Version: 5
Forum text is available under the terms of the GNU Free Documentation License.

Pagename: Charcoal