Gaseous fuels
Excess air
λ
x =
Standard density, air
ρn,A [kg/m³n,A]
1.293
Material value
Unit
Natural gasL
Natural gasH
Propane
PropaneButane
Butane
Natural gasGZ35
Natural gasGZ41.5
Natural gasGZ50
Net calorific value
Hi
kWh kgF
10.65
13.20
12.87
12.83
12.70
7.98
9.65
10.86
kWh m³n,F
8.83
10.35
25.89
27.96
34.39
7
8
9
Gross calorific value
HS
11.80
14.62
13.98
13.92
13.75
8.86
10.80
12.01
9.78
11.46
28.12
30.34
37.23
7.77
8.95
9.95
Fuel standard density
ρn,F
kg m³n,F
0.829
0.784
2.011
2.18
2.708
0.877
Stoichiometric air demand
LST
kgA kgF
13.10
16.24
15.57
15.51
15.36
9.84
Standard density, flue gas
ρ>n,FG,st
(λ=1)
kg m³n,FG
1.2366
1.2374
1.2650
1.2664
1.2699
1.2346
ρn,FG
(λ=x)
1.2451
1.2459
1.2693
1.2706
1.2735
1.2432
Wobbe index
Wi
kWh m³
11.03
13.29
20.76
21.53
23.76
8.50
9.99
11.24
Dew point
tCo
°C
56.9
57.0
53.1
52.9
52.4
56.7
Water generation1)
wspec,H2O
gH2O kWh
159.4
158.5
126.9
125.4
122.0
161.8
176.0
156.4
CO2 emissions1)
wspec,CO2
gCO2 kWh
201.3
202.6
232.6
234.3
238.5
197.6
222.2
197.5
SO2 emissions1)
wspec,SO2
mgSO2 kWh
0.0
Flue gas mass flow rate1)
ṁspec
kgFG kWh
1.570
1.552
1.529
1.530
1.605
1.733
1.540
Liquid fuels
ρn,A[kg/m³n,A]
Fuel oil EL
Fuel oil EL,lowsulphur
Fuel oil SA
Medium fuel oil HLSchwechat
Medium fuel oilCLU3
Netcalorific value
11.89
11.28
11.64
11.40
kWh I
9.91
10.98
9.70
10.59
Grosscalorific value
11.96
12.38
12.05
10.32
11.19
kg m³
833.6
973.6
928.6
Stoichiometricair demand
14.45
14.46
13.89
14.19
13.71
Standard density flue gas
ρn,FG,st (λ=1)
1.2923
1.3063
1.2996
1.3097
ρn,FG (λ=x)
1.2924
1.3042
1.2985
1.3071
48.6
46.0
47.2
45.4
Acid dew point
tacid cond
124.0
97.3
136.4
123.2
141.5
100.5
88.7
93.7
83.9
266.4
266.9
285.2
275.8
280.6
108.4
2.6
597.9
99.2
1,213.8
1.542
1.543
1.567
1.548
1.531
Minimum feed water temperature as a function of fuel sulphur content
Fuel oil S
Pinch-point diagram for gas
Boiler
Boiler + economiser
Boiler + economiser + condensing heat exchanger (with z = 0.3 / α = 12%)
Boiler + economiser + condensing heat exchanger (with z = 0.5 / α = 20%)
Boiler + economiser + condensing heat exchanger (with z = 1 / α = 34%)
Boiler + economiser + air preheating (20°C to 65°C)
Boiler + economiser + feed water cooling (with z = 0.3)
Example:
KCondensate accumulation rate
c = ṁCo / ṁS
Make-up water rate
z = 1 – c
UL-S
10,000 x 16
System steam output
10,000 kg/h with pavg = 13 bar
Surface blowdown rate
5 %
Case
Component
Efficiency
Component parts
Total
1
88.9 %
---
2
88.9 % + 6.5 %
95.4 %
3
Boiler + economiser + condensing heat exchanger (with z1) = 0.3 / α2) = 12 %)
88.9 % + 6.5 % + 2.8 %
98.2 %
4
Boiler + economiser + condensing heat exchanger (with z = 0.5 / α = 20 %)
88.9 % + 6.5 % + 3.8 %
99.2 %
5
Boiler + economiser + condensing heat exchanger (with z = 1 / α = 34 %)
88.9 % + 6.5 % + 7.6 %
100.9 %
6
88.9 % + 6.5 % + 1.7 %
97.1 %
88.9 % + 6.5 % + 0.6 %
96.0 %
Case studies for combinations of measures for optimum heat recovery
1) z = make-up water rate
2) α = condensate accumulation rate
Pinch-point diagram for oil
