YOKOGAWA av550g, User Manual

Page: 124 / 213

<8. Detailed Data Setting>
8-15
IM 11M12D01-01E
Enter
F8-19E.ai
Set period over which
average is calculated:
1 h

Set period over which
maximum and minimum is
stored: 2 4 h
Averaging
Figure 8.19 Average / Max. / Min. Setup
<Default setting>
[Set period over which average is calculated] is set to 1hr, and [Set period over which maximum and
minimum] is stored is set to 24 hours prior factory shipment or after data initialization.
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 X 100 (%)
H
gas
: Water content of sample 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:
(water vapor caused by combustion and water vapor contained in the exhaust gas)
Moisture quantity =
= (Gw + Gw1)/G x 100
=
where,
Ao : Theoretical amount of air per unit quantity of fuel, m 3 /kg (or m 3 /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 /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 /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 /m 3 )
Go: Theoretical amount of dry exhaust gas per unit quantity of fuel, m 3 /kg (or m 3 /m 3 )
m: Air ratio
X : Fuel coefficient determined depending on low calorific power of fuel, m 3 /kg (or m 3 /m 3 ) ....... 3 in Table 8.7
Z : Absolute humidity of the atmosphere, kg/kg ....... Figure 8.16
X + Ao x m
Gw + (1.61 x Z x m x Ao )
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
x 100
..... Equation 1
............ Equation 2
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 Equations 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).