Environmental Engineering Reference
In-Depth Information
with a = x + 1
2z
The air-to-fuel ratio (kg
=
4y
−
1
=
kg
−1
)is
air
fuel
=
4
:
76a
1
MW
air
MW
fuel
stoichiometric
Now, x, y, and z follow from calculating the number of moles of the ele-
ments i in the fuel. These are simply calculated for, e.g., 100 g of fuel as
mass
i
/MW
i
:
x = (45.6/12.011) = 3.80, y = (6.6/1.00797) = 6.5, and z = (47.8/15.9994)
= 2.99
Then, a = 3.94.
MW
air
and MW
fuel
are calculated as follows:
mol
−1
MW
air
=0
:
21
2
15
:
9994 + 0
:
79
2
15
:
9994 = 28
:
85 g
mol
−1
(100 g of fuel was taken as starting point of the cal-
culation, and it concerns 1 mol of fuel considered).
Now, the required air-to-fuel ratio can be calculated as
MW
fuel
= 100 g
air
fuel
=
4
:
76a
1
MW
fuel
=
4
MW
air
:
76
3
:
99
28
85
100
=5
:
kg
−1
:
41 kg
1
stoichiometric
b. The volume percentage of CO
2
in the wet flue gas is
x
x+
2
y+3
3
:
80
vol
:
%
CO
2
= 100
76a
= 100
94
=17
:
3
%
80 +
2
:
3
:
6
:
5+3
:
76
3
:
c. The volume percentage of CO
2
in the dry flue gas is
x
x+3
3
:
80
vol
:
%
CO
2
= 100
76a
= 100
94
=20
:
4
%
:
3
:
80 + 3
:
76
3
:
Question
: Does the use of a cooler lead to an entirely dry flue gas? Which process
parameter determines the wetness of the gas entering the analyzer?
2.6 HEATING VALUES
The heating value (also called calorific value) of biomass is a measure of the
thermal energy released upon complete combustion, and it is a key property for deter-
mining energy balances and performing flame temperature calculations concerning
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