What is a stoichiometric combustion?
We call a stoichiometric combustion a combustion without excess or lack of air, where all available oxygen is completely consumed. Assuming that nitrogen reacts only in negligible proportions and is found after. combustion in molecular form, the general equation of a stoichiometric combustion.
Is stoichiometric combustion possible?
Stoichiometric combustion is a theoretical position where the optimal amount of oxygen and fuel mix generates the most heat possible, achieving maximum combustion efficiency. There are no unburnt combustibles and no excess air. It is something to strive for, though, in reality, it does not exist.
What is theoretical combustion?
Stoichiometric or Theoretical Combustion is the ideal combustion process where fuel is burned completely. A complete combustion is a process burning all the carbon (C) to (CO2), all the hydrogen (H) to (H2O) and all the sulphur (S) to (SO2).
What is a stoichiometric engine?
Engine management systems The stoichiometric mixture for a gasoline engine is the ideal ratio of air to fuel that burns all fuel with no excess air. For gasoline fuel, the stoichiometric air–fuel mixture is about 14.7:1 i.e. for every one gram of fuel, 14.7 grams of air are required.
Why is stoichiometric combustion basically impossible?
Although theoretically stoichiometric combustion provides the perfect fuel to air ratio, which thus lowers losses and extracts all of the energy from the fuel; in reality, stoichiometric combustion is unattainable due to many varying factors. Heat losses are inevitable thus making 100% efficiency impossible.
How do you calculate stoichiometric ratio?
Thus, to calculate the stoichiometry by mass, the number of molecules required for each reactant is expressed in moles and multiplied by the molar mass of each to give the mass of each reactant per mole of reaction. The mass ratios can be calculated by dividing each by the total in the whole reaction.
Is there a difference between complete combustion and theoretical combustion?
No, they are not identical. The theoretical combustion is also complete combustion, but in theoretical combustion there is no uncombined oxygen in product gases whereas complete combustion may require excess air for combustion results in uncombined oxygen in product gases.
What are stoichiometric calculations?
Stoichiometric Calculations are mostly based on chemical formulas. Formula Mass: It is defined as the sum of the atomic weights of each atom present in the molecule of the substance. For example formula mass of Na2S is calculated as 2(23) + 1(32) = 78.
How is stoichiometry used in cars?
The stoichiometric point is a term commonly used to describe the ideal fuel/air ratio in a combustion engine. The stoichiometric air-fuel ratio for gasoline is 14.7 to 1 by weight. Theoretically, at this ratio all of the fuel will be burned using all of the oxygen in the air.
What are the components of stoichiometric combustion?
Stoichiometric Combustion. The purpose of combustion is to consume fuel efficiently to produce heat. There are three components of combustion: fuel, oxygen and heat. The most common fuel sources in a combustion process are fossil fuels; natural gas, oil and coal. Fossil fuels are hydrocarbons; organic compounds containing carbon and hydrogen.
Why is the combustion process not stoichiometric?
With unburned components in the exhaust gas such as C, H 2, CO, the combustion process is uncompleted and not stoichiometric . The combustion process can be expressed: To determine the excess air or excess fuel for a combustion system we starts with the stoichiometric air-fuel ratio.
What is the stoichiometry of combustion of fossil fuels?
Fossil fuels are mainly compounds of carbon and hydrogen (hydrocarbons – CmHn). The reaction of its oxidation can by written by the equation of stoichiometry: CmHn + (m + n/4)O 2 →→→→mCO 2 + n/2H 2O 1 mol + (m + n/4)moles →→→→(m +n/2)moles. This is an equation of stoichiometry of combustion.
What is the stoichiometric air to fuel ratio?
The stoichiometric air/fuel ratio (AFR) can be calculated from the reaction equation (g/g). For gas AFR is usually determined in m3/m 3. The actual combustion air depends also on the assumed air excess (equivalence ratio or stoichiometric ratio).