02-02-2013, 01:04 PM
Stoichiometric Calculations
Stoichiometric Calculations.ppt (Size: 1.22 MB / Downloads: 313)
Applications of the Combustion Equation
(1) Stoichiometric proportions for finding the correct air supply rate for a fuel (2) Composition of the combustion products is useful during the design, commissioning and routine maintenance of a boiler installation
On-site measurements of flue gas composition and temperature are used as a basis for calculating the efficiency of the boiler at routine maintenance intervals.
Combustion Air Requirements: Gaseous Fuels
Calculating the air required for gaseous fuels combustion is most convenient to work on a volumetric basis.
The stoichiometric combustion reaction of methane is :CH4 + 2O2 → CO2 + 2H2Owhich shows that each volume (normally 1 m3) of methane requires 2 volumes of oxygen to complete its combustion.
Flue Gas Composition-Gaseous Fuels
The composition of the stoichiometric combustion products of methane is: 1 volume CO27.52 volumes N22 volumes H2O
Given a total product volume, per volume of fuel burned, of 10.52 if water is in the vapor phase, or 8.52 if the water is condensed to a liquid.The two cases are usually abbreviated to “wet” and “dry”.
Combustion Air Requirements-Solid and Liquid Fuels
The way in which the combustion equation is used reflects the available information on the analysis of the solid or liquid fuels.This takes the form of an element-by-element analysis (referred to as an ultimate analysis) which gives the percentage by mass of each element present in the fuel.
An example of an ultimate analysis of a liquid fuel (oil) might be :Component % by massCarbon © 86Hydrogen(H2) 14