Types of Fuel. Combustion is one of the most common sources of energy used by people.
There are several types of Fuel of aggregation state: solid fuel, liquid fuel and gaseous fuel. Accordingly it is possible to give examples: solid fuels - coke, coal, liquid - petroleum and petroleum products (kerosene, gasoline, oil, fuel oil, gaseous fuels are gases (methane, propane, butane, etc.)
An important parameter of each fuel type is its calorific value, in many cases it determines the direction of fuel usage.
Calorific value is the amount of heat that is released during combustion of 1 kg (or 1 m3) of fuel at a pressure of 101.325 kPa and 00C, i.e. at normal conditions.
Expresses calorific value in units of kJ/kg (kilojoule / kg). Naturally, different fuels have different calorific value:
- Kerosene - 35000
- wood - 18850
- gasoline - 46000
- methane - 50000
It is seen that the methane of these fuels has the highest calorific value.
In order to receive the heat contained in the fuel, it must be heated it to the ignition temperature and, of course, if sufficient amount of oxygen. In the process of chemical reactions - combustion - generates a large amount of heat.
How is burning coal. The coal is heated with the action of oxygen, forming carbon oxide (IV), i.e. CO2. Then CO2 in the upper layer of hot coals reacts with the coal again and is resulting a new chemical substance oxide of carbon (II) or CO - carbon monoxide. But this substance is very active and once in the air a sufficient amount of oxygen, the substance CO burns with a blue flame with formation of carbon dioxide CO2
Did you ever ask yourself the question, what is the flame temperature?! We all know that, for example, to do certain chemical reactions required to heat of the reactants. For such purposes in laboratories, use gas burner running on natural gas, having a good calorific value. When burning fuel - gas, chemical energy of combustion is converted into thermal energy. For gas burners, the flame can be presented as:
- the highest point of the flame is one of the hot spots of the flame. The temperature at this point approximately 15400C - 15500C;
- just below (about 1/4 part) - in the middle of the flame is the hottest area 15600C;
- next is the lowest point of the flame where the temperature is only 3500C