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Combustion Problems

The document discusses calculating stoichiometric air to fuel ratios (A/F) by mass for different biomass and coal fuel mixtures based on their elemental compositions and molecular formulas during combustion. It provides examples of calculating the moles of oxygen, air, and biomass fuel required based on balanced combustion reactions. The final questions ask to calculate A/F by mol and mass for another coal mixture, and to repeat it accounting for moisture and ash content in the as-received analysis.

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Rehman Mani
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337 views9 pages

Combustion Problems

The document discusses calculating stoichiometric air to fuel ratios (A/F) by mass for different biomass and coal fuel mixtures based on their elemental compositions and molecular formulas during combustion. It provides examples of calculating the moles of oxygen, air, and biomass fuel required based on balanced combustion reactions. The final questions ask to calculate A/F by mol and mass for another coal mixture, and to repeat it accounting for moisture and ash content in the as-received analysis.

Uploaded by

Rehman Mani
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PPTX, PDF, TXT or read online on Scribd
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Combustion

Dr. M. Azam Saeed


Calculate the stoichiometric F/A by mass of the
biomass fuel mixture based on the following
elemental analysis;
 C 40% H 20% O 20% N 10%
S 10%

Assume 1 mole of biomass mixture. Also assume


the conversion of NO’x and SO’x in the combustion
products.

QA 2
Calculate the stoichiometric A/F by mass of the
10 mol of biomass fuel mixture (Taking 1 mol
of C basis for ratios) with the following
elemental analysis;
C 30% H 25% O 20% N 15%
S 10%

Assume the conversion of NO’x and SO’x in the


combustion products.

QA 3
Basis: 1 mol of Carbon for calculating the ratios
as below;
H/C 0.83
O/C 0.67
N/C 0.5
S/C 0.34

QA 4
3CH0.83O0.67N0.5S0.34+ 5.145O2

3CO2+ 1.25H2O+ 1.5NO2+ 1.02SO2

QA 5
Net mole of O2 req= 5.145 mol

Mole of air required= 5.145/0.21


= 24.5 mol

Mass of air required = 24.5 x 28.84


= 706.6 g

QA 6
Mass of biomass fuel mixture (CH0.83O0.67N0.5S0.34)=

3 (12+ 0.83+ 16x0.67+ 14x0.5+ 32x0.34)

= 124.3 g
So,
A/F by mass = 706.6/124.3= 5.68

QA 7
Assignment
Calculate the g of fuel per m3 of air for the 12
moles of coal mixture with the following ultimate
analysis
%C 55%
%H 6%
%O 33%
%N 3%
%S 3%

QA 8
Assignment
 Calculate the Stoichiometric A/F by mol and by
mass of coal mixture with the following ultimate
analysis
%C 65%
%H 4%
%O 26%
%N 2%
%S 3%
If the % moisture and ash are 12 and 15
respectively, repeat the calculations for as received
analysis.
QA 9

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