ANNEX D
Coefficients of the fuels and Formulas
The following chart, lists the coefficients of the memorised fuels, used for calculating losses and efficiencies.
Details of the coefficients of the fuels:
Coefficients for calculating combustion efficiency
Fuel A1 USA
B
CO2t
(%)
PCI
(KJ/Kg)
PCS
(KJ/Kg)
M air
(Kg/Kg)
M H
2
O
(Kg/Kg)
V dry gas
(m
3
/Kg)
•
CO2 t: The value of CO
2
generated by combustion in stoichiometric condition, i.e. without excess Oxygen
and therefore maximum.
•
A1, B: Also please have a look at the Siegert formulas from the European standard EN50379-1 (in the
following).
A1 is the parameter in the Siegert Formula when the O
2
measurement is available.
Note: - Please also consider that in the U.S. usually the A1 parameter is the same as the
'European' A1 BUT divided by 2.
Flue gas heat losses are calculated from measured oxygen content according to the relationship:
q
A
= (t
A
- t
L
) x A1
21
21 - O
2
+
Flue gas heat losses are calculated from measured carbon dioxide content according to the relationship:
q
A
= (t
A
- t
L
) x A1
CO
2
t
CO
2
+
Air index is calculated with the formula:
λ=21/(21-O
2
), where O
2
is the oxygen residual concentration in the combustion smokes.
Air excess is calculated with the formula:
e=(λ-1)*100
•
CO conv: Conversion coefficient from ppm to mg/KWh. It can be expressed as a function of the gas density
(CO in this case) and the volume of the dry smoke.
•
NO conv: Same as CO conv, but for NO.
•
NOx conv:Same as CO conv, but for NOx.
•
SO2 conv: Same as CO conv, but for SO2.
•
PCI: Potere Calorifico Inferiore. Italian for LHV (Lower Heating Value).
•
PCS: Potere Calorifico Superiore. Italian for HHV (Higher Heating Value).
•
m H2O: Mass of the air produced (per each Kg of fuel) in the combustion in stoichiometric condition.
•
m Air: Mass of the air needed for combustion in stoichiometric condition.
•
V g.d.: Volume of dry smokes produced in the combustion.
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