Yokogawa Multi Channel Oxygen Analyzer System ZR22/AV550G User Manual
Page 145
IM 11M12D01-01E
8-19
8. Detailed Data Setting
8.5.3 "Fuel" Setup: Humid Exhaust Gas or "Dry" Equivalent Oxygen Content
This instrument can convert between "humid" gas measurements and "dry" equivalents:
100 -
=
gas
dry
H
y
Y
Fuelequ.eps
X 100 (%)
H
gas
: Water content of measured gas %H
2
O
Y
dry
: Dry oxygen equivalent (%O
2
)
Y : Oxygen concentration in moist gas (%O
2
)
To convert between "humid" and "dry" gas measurements, the water content H gas is
computed.To compute the water content, four parameters Ao, Gw, X and Z are required,
and the following expression is used:
Moisture quantity =
= (Gw + Gw1)/G x 100
=
Ӏ{
Gw + (1.61 x Z x m x Ao
}
{
X + Ao x m
}
where,
Ao : Theoretical amount of air per unit quantity of fuel, m
3
/kg (or m
3
) ... (2) in Table 8.7
G: Actual amount of exhaust gas (including water vapor) per unit quantity of fuel,
m
3
/kg (or m
3
)
Gw : Water vapor contained in exhaust gas per unit quantity of fuel (by hydrogen
and moisture content in fuel), m
3
/kg (or m
3
) ............(1) in Table 8.7
Gw1: Water vapor contained in exhaust gas per unit quantity of fuel (moisture content
in air), m
3
/kg (or m
3
)
Go: Theoretical amount of dry exhaust gas per unit quantity of fuel, m
3
/kg (or m
3
)
m: Air ratio
X : Constant determined depending on low calorific power of fuel ....... (3) in Table 8.7
Z : Absolute humidity of the atmosphere ....... Figure 8.20
(water vapor caused by combustion and water vapor contained in the exhaust gas)
x 100
actual exhaust gas(including water vapor) per fuel
+ (water vapor contained in air for combustion)
x 100
Gw + (1.61 x Z x m x Ao)
Go + Gw [(m - 1) Ao + (1.61 x Z x m x Ao)]
x 100
..... Equation 1
.............................................. Equation 2
F8.20E.eps
Fill in the boxes with fuel parameters in Equation 2 above to calculate the moisture
content. Use Ao, Gw and X shown in Table 8.7. If there are no appropriate fuel data in
Table 8.7, use the following equations for calculation. Find the value of “Z” in Equa-
tions 1 and 2 using Japanese Standard JIS B 8222 etc. If a precise measurement is not
required, obtain the value of “Z” using a graph for the absolute humidity indicated by a
wet and dry bulb hygrometer (Figure 8.20).