Charcoal is a waste consisting of pure carbon that results from the process of dewatering plant materials .
A method of preparation called destructive distillation (burning in isolation from air) is the method called by the Arabs.
The presence of plant tissues in charcoal and charcoal indicates that they are of plant origin. Charcoal is made by man by heating wood, and its black color is caused by the presence of the carbon element. As for the fact that charcoal is lighter than wood, it is because wood loses a quantity of water when it is converted into charcoal , and the percentage of pores in it increases. The water in the wood is also responsible for the thick smoke when it is burned. As for the fact that coal is heavier than charcoal , it is due to the mineral components that are found in coal and not found in charcoal .
How to make charcoal
Wood charcoal is another form of impure carbon. Wood is collected in piles, covered with earth, and heated for about ten days. Heating is done by burning a small part of the wood due to the entry of a small amount of air. This burning part supplies the rest of the wood with the heat needed to heat it up and turn it into charcoal . In order to convert wood into charcoal , it is necessary to get rid of the oxygen and hydrogen present in the organic wood compounds (cellulose). This is done by a chemical reaction in which the oxygen and hydrogen are removed from the cellulose, and it turns into a new organic compound that contains less oxygen and hydrogen, and the percentage of carbon increases in it.
How is wood carbonized?
The wood is collected in piles, covered with earth, and heated for about ten days. Heating is done by burning a small part of the wood due to the entry of a small amount of air. This burning part supplies the rest of the wood with the heat needed to heat it up and turn it into charcoal .
In order to convert wood into charcoal , it is necessary to get rid of the oxygen and hydrogen present in the organic wood compounds ( cellulose ). This is done by a chemical reaction in which the oxygen and hydrogen are removed from the cellulose, and it turns into a new organic compound that contains less oxygen and hydrogen, and the percentage of carbon increases in it.
stages of coal formation
Wood is heated in a kiln where it passes through specific stages on its way to becoming charcoal . The formation of coal under laboratory conditions has been studied and has been recognized in the next stages of the conversion process.
From 20 to 110 degrees C
Wood absorbs heat to dry and get rid of its moisture as water vapor (steam). The temperatures are kept at 100 °C until the wood turns harden.
at 110-270°C
The water is finally discarded and the wood begins to decompose, producing some carbon monoxide, carbon dioxide, acetic acid, and methanol.
at 270-290°C
This is the point at which wood begins to decompose and collapse continues on its own. Wood does not cool below this temperature. Mixed gases and vapors continue to rise along with some tar.
at 290-400°C
As the wood structure continues to collapse, the vapors emitted are combustible gases carbon monoxide, hydrogen and methane with carbon dioxide and condensable vapors of water, acetic acid, methanol, acetone, etc., and tar that begins to sublimate with the rise in temperature.
at 400-500°C
At 400 °C the transformation of wood into charcoal is practically complete. Coal at this temperature still contains appreciable amounts of tar, perhaps 30% of its weight, trapped in the hull. Thus the carbon content of coal is fixed to about 75% which is normal for good quality commercial coal . To completely get rid of the tar, the temperature of the coal is raised to about 500 degrees Celsius for a reasonable period.
Characteristics of good charcoal
There are many factors that determine the quality of coal produced by any method of production, and these factors are:
- The quality of the wood used: the type of wood is of great importance to its quality. Since time immemorial, the Egyptian farmer knows this information. For example, in Egypt and the Arab countries, they prefer charcoal produced from citrus trees such as orange trees, guava trees, and mangoes , which are the best types for producing good charcoal . This is due to the components of cellulose, the main component of wood, and the varying proportions absorption of soil components.
- Carbon percentage: Temperatures have a great importance in the quality of the produced coal , and whenever the temperature exceeds 400 degrees Celsius, the quality of the resulting coal decreases, as carbon decreases, which is the main component of good coal.
- Moisture percentage in coal : It is also a factor in the quality of coal . The higher the moisture content, the lower its quality.
- The quantity and color of the resulting ash: It is also determined by the main component of the wood used and the amount of salts and components that permeate the cellulose.
- The size of the coal : It results from the manufacture and circulation of coal and its transportation from one place to another. As a result, a good percentage of the coal is broken, which is not suitable for use. The appropriate size is also important.
Charcoal uses
Charcoal is used in direct burning to obtain energy. It is usually limited to its use for some household purposes such as heating, cooking or grilling. In Mexico, Peru, Spain, Paraguay and other Latin countries, charcoal has been used for centuries as fuel for brasero fireplaces . As for the countries where there is a surplus of forest wood, it can be converted into charcoal and then used in some large projects such as generating electricity. Just as the burning time of an amount of charcoal is longer than the burning time of a similar amount of wood, charcoal has a greater calorific value than wood.
A form of wood charcoal called activated carbon is used in filters and gas masks to remove toxic fumes. It has countless small holes in its surface that are ideal for trapping vapors and is made by allowing the charcoal to burn briefly with oxygen at the end of the charcoal making process . Wood charcoal is often used as a fuel for barbecue and can be shaped into sticks as a material for drawing. And since activated charcoal has a high adsorption capacity, that is, it attracts materials to its surface, it can remove toxic gases and unpleasant odors from the air.. Therefore, this charcoal is used in ventilation systems in spacecraft and as masks for kitchen stoves. It is also used to purify liquids. Like water in fish tanks. The dirty water in the basin is passed over activated charcoal to remove its dirt, then it is returned pure to the basin.. It can be put in the refrigerator if it has bad smells, so it will get rid of the bad smells that are in the refrigerator..
Characteristics of good charcoal
There are many factors that determine the quality of coal produced by any method of production, and these factors are:
1- The quality of the wood used
Where the type of wood is of great importance to its quality, and since time immemorial, the Egyptian farmer knows this information. For example, in Egypt and the Arab countries, they prefer charcoal produced from the wood of citrus trees such as orange trees, guavas, mangoes, and olives, which are the best types for producing good charcoal . This is due to the components of cellulose, the main component of wood, and the varying rates of its absorption of soil components. .
2- Carbon percentage
And temperatures are of great importance in the quality of the produced coal , and whenever the temperature is higher than 400 degrees Celsius, the quality of the produced coal decreases , as carbon decreases, which is the main component of good coal .
3- The percentage of moisture in the coal
It is also a factor in the quality of coal , as the higher the humidity, the lower its quality.
4- The quantity and color of the resulting ash
It is also determined by the main component of the wood used and the amount of salts and components that permeate cellulose.
5- The size of the coal
As a result of the coal industry , its circulation and its transportation from one place to another, a good proportion of the coal is broken , which is not suitable for use. The appropriate size is also important.
Health effects resulting from the coal industry
The main harm to human health results from inhalation of gases emitted from the burning process. These gases cause many respiratory diseases that differ according to the type of inhaled gas. It is known that sulfur oxides lead to inflammatory reactions in the bronchi (Emphysema). While hydrocarbon gases, such as those emitted from car exhausts and generators, lead to cancerous diseases. As for carbon monoxide, it has the ability to unite with hemoglobin 200 times more than oxygen, and thus it leads to acute poisoning, headache, dizziness, nausea and respiratory failure. In the case of a high concentration of gas and the body continues to be exposed to it, it leads to chronic symptoms, such as poor memory, lack of productivity at work, sleep and behavior disorders, and an increase in cholesterol levels. As for carbon dioxide, its presence in the air at a low concentration may lead to rapid breathing, headaches, mental confusion, and ataxia. If its concentration exceeds 5%, it leads to loss of consciousness and death. There are also health damages resulting from sulfur oxide, as this gas turns into sulfuric acid when it comes into contact with the moist surfaces of the mucous membranes, and this results in infections and chronic diseases of the respiratory system. Nitrogen oxides irritate the alveoli in the lungs, while the accumulation of dust in them can lead to fibrosis and death. It is clear from the foregoing that the problem in the coal industry is its negative effects on public health and the environment, as it emits many gases such as carbon monoxide, carbon dioxide, sulfur dioxide and some other wastes that affect agricultural and water wealth. And it is more dangerous if the coal- producing areas are close to residential communities, as these gases and fumes affect not only the workers in production, but also the entire population of the region.