Fuel Type
Fossil fuels, such as coal, petroleum, and natural gas.
Nuclear fuel, such as uranium and plutonium. In the nuclear fuel, the heat obtained from the decomposition chain reaction of atoms through radioactive events.
Other fuels, such as: the rest of the plants (biomass), vegetable oils (straight vegetable oil), animal oils, biofuels / biodiesel.
Fuel Composition
Fuel is generally composed of the elements: C (carbon), H (hydrogen), O (oxygen), N (nitrogen), S (sulfur), Abu, etc.. These elements can be divided into two types, namely: Combustible matter is that if the elements of fire will produce heat, the chemical elements, namely, C, H and S. Non-combustible matter are other elements contained in the material but can not burn fuel, such elements is O, N, mineral matter or ash and water.
Fuel properties
a. Calorific Value (Heating Value)
Heat value of fuel is produced by the complete combustion of one kilogram or unit weight of solid or liquid fuel or one cubic meter or one unit volume of fuel gas, the standard state.
Top fuel value or "gross heating value" or "higher heating value" (HHV) is the heat produced by the complete combustion of a unit weight of solid or liquid fuels, or a unit volume of fuel gas, at a constant pressure, a temperature of 25 ° C, when all the water initially in liquid form after combustion condenses back into liquid.
Lower fuel value or "net heating value" or "lower heating value" (LHV) is the amount of heat equal to the reduced value of the heat on the heat required by the water contained in the fuel and the water formed from the combustion of fuel
b. Water levels in the fuel (water content)
The water contained in the solid fuel consists of: internal water content or water crystals, which are chemically bound water, the water content of the external, ie water attached to the surface of the material and physically bound. Water in the liquid fuel is an external water, the water acts as a bully. Water in the fuel gas is water vapor mixed with the fuel.
The water contained in the fuel causes a decrease in fuel quality because:
lower fuel value and requires certain amount of heat for evaporation,
lower the flash point,
slow down the combustion process,
increase the volume of exhaust gas.
c. Flash Point (Flash Temperature)
Flash point is the lowest temperature at which vapors are formed from a combustible fuel source heat when given the material itself without burning (burning shortly).
d. Point Fuel (Combustion / fire point temperature)
The point is the temperature at which the fuel is ignited materials will burn continuously when given heat source (usually about 30-40 ° C higher than the flash point).
e. Flammable point (Auto Ignition Temperature)
If the fuel mixture introduced into the combustion chamber and gradually heated, it will burn itself at a certain temperature, this temperature is called "self-ignition temperature" or sulut point. Sulut point is the lowest temperature at which the material can be burned by itself. Usually the "operating temperature" is lower than the point sulut a combustible material. Example: natural gas about 595 º.
fuel
Flash point ° C
Autoignition º C
methane
-188
537
Ethan
-135
472
propane
-104
470
butane
-60
365
n-Octane
10
206
I - Octane
-12
418
n-Cetan
135
205
methanol
11
385
ethanol
12
365
f. viscosity
Viscosity is the nature of the fuel (fuel oil) is very important that enables the fuel can be pumped or not (pumpable) and easily turned on or not (flamable).
g. sulfur content
In the sulfur contained in the fuel reacts participating in the combustion process with the following reaction:
S + O2 ---> SO2
2 SO2 + O2 ---> 2 SO3
Furthermore, SO2 and SO3 reacts with water vapor (H2O) derived from the combustion air and
of the fuel itself, with the following reaction:
SO2 + H2O ---> H2SO3
2 SO2 + O2 ---> 2 SO3
The results of the above reaction is entrained in flue gases of combustion so as to have the nature of the acid corrosion. However, the corrosion rate of the flue gas depends on:
The concentration of SO3 and H2O
The temperature of the flue gas in the stack, always kept higher than the dew point
