Gas Quality Stakeholders’
Technical Committee Meeting
August 9, 2005
Natural Gas Quality:
Power Turbine Performance
During Heat Content Surge
William Walters
Aspen Environmental Group
Sponsored by the California Energy Commission
CALIFORNIA ENERGY COMMISSION
Summary of Findings
• Uncontrolled NOx emissions increase with increasing
natural gas heat content number, but that increase is
different for each turbine.
• Controlled NOx was not found to increase, the
emission controls were able to compensate
• Additional ammonia was used for the gas turbines with
Selective Catalytic Reduction in order to compensate.
• Additional data is necessary to determine full impact to
the natural gas fired power plants.
• Study will be published in draft form for comment
sometime in the next month.
CALIFORNIA ENERGY COMMISSION
Natural Gas Excursion Event
•
•
•
PG&E pipeline coming
from Canada
experienced heat
content excursion for
three days.
Heat content excursion
due to outage at a
liquids extraction plant
in Canada.
Operating and fuel data
from four power plants
were obtained around
the excursion event.
CALIFORNIA ENERGY COMMISSION
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
Heat Content (Btu/scf)
1100
1070
1060
1355
1050
1040
1350
1030
1000
8-Jun-05
9-Jun-05
10-Jun-05
11-Jun-05
12-Jun-05
Wobbe Number
Pipeline Natural Gas Heat Content and Wobbe
1370
1090
1365
1080
1360
Redding
Delta
Delta
Wobbe
1345
1020
1010
1340
1335
13-Jun-05
CALIFORNIA ENERGY COMMISSION
Major Components - Pittsburg
93
5
92
4
91
3
90
2
87
10-Jun
11-Jun
12-Jun
Ethane, Propane, and Inerts (mole %)
96
12:00 AM
2:00 AM
4:00 AM
6:00 AM
8:00 AM
10:00 AM
12:00 PM
2:00 PM
4:00 PM
6:00 PM
8:00 PM
10:00 PM
12:00 AM
2:00 AM
4:00 AM
6:00 AM
8:00 AM
10:00 AM
12:00 PM
2:00 PM
4:00 PM
6:00 PM
8:00 PM
10:00 PM
12:00 AM
2:00 AM
4:00 AM
6:00 AM
8:00 AM
10:00 AM
12:00 PM
2:00 PM
4:00 PM
6:00 PM
8:00 PM
10:00 PM
12:00 AM
2:00 AM
4:00 AM
6:00 AM
8:00 AM
10:00 AM
12:00 PM
2:00 PM
4:00 PM
6:00 PM
8:00 PM
10:00 PM
Methane (mole %)
Pipeline Gas Composition
7
95
6
94
Methane
Ethane
Propane
Inerts
89
88
1
0
13-Jun
CALIFORNIA ENERGY COMMISSION
12:00 AM
2:00 AM
4:00 AM
6:00 AM
8:00 AM
10:00 AM
12:00 PM
2:00 PM
4:00 PM
6:00 PM
8:00 PM
10:00 PM
12:00 AM
2:00 AM
4:00 AM
6:00 AM
8:00 AM
10:00 AM
12:00 PM
2:00 PM
4:00 PM
6:00 PM
8:00 PM
10:00 PM
12:00 AM
2:00 AM
4:00 AM
6:00 AM
8:00 AM
10:00 AM
12:00 PM
2:00 PM
4:00 PM
6:00 PM
8:00 PM
10:00 PM
12:00 AM
2:00 AM
4:00 AM
6:00 AM
8:00 AM
10:00 AM
12:00 PM
2:00 PM
4:00 PM
6:00 PM
8:00 PM
10:00 PM
Butane and Pentane (mole %)
0.500
0.350
0.250
0.015
0.200
0.150
0.000
10-Jun
11-Jun
12-Jun
C6 Plus (mole %)
Pipeline Gas Composition
Minor Components - Pittsburg
0.035
0.450
0.030
0.400
0.025
0.300
0.020
Butanes
Pentanes
C6Plus
0.010
0.100
0.050
0.005
0.000
13-Jun
CALIFORNIA ENERGY COMMISSION
6-Jun-05
9-Jun-05
7-Jun-05
10-Jun-05
8-Jun-05
11-Jun-05
9-Jun-05
12-Jun-05
10-Jun-05
13-Jun-05
11-Jun-05
12-Jun-05
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
Btu/scf (HHV)
• Sutter Fuel Data
12:00 PM
4:00 PM
8:00 PM
12:00 AM
4:00 AM
8:00 AM
12:00 PM
4:00 PM
8:00 PM
12:00 AM
4:00 AM
8:00 AM
12:00 PM
4:00 PM
8:00 PM
12:00 AM
4:00 AM
8:00 AM
12:00 PM
4:00 PM
8:00 PM
12:00 AM
4:00 AM
8:00 AM
12:00 PM
4:00 PM
8:00 PM
12:00 AM
4:00 AM
8:00 AM
12:00 PM
4:00 PM
8:00 PM
12:00 AM
4:00 AM
8:00 AM
12:00 PM
4:00 PM
8:00 PM
12:00 AM
4:00 AM
8:00 AM
12:00 PM
• LMEC Fuel Data
Heat Content (Btu/scf)
Turbine Fuel Heat Content Variability
1050
1040
1030
1020
1010
1000
990
980
970
14-Jun-05
1,080.00
1,070.00
1,060.00
1,050.00
1,040.00
1,030.00
1,020.00
1,010.00
13-Jun05
CALIFORNIA ENERGY COMMISSION
Power Plant Descriptions
• All of the power plants that were monitored are combined
cycle power plants.
• Redding is a “muni”, while Sutter, Delta and LMEC are
Calpine owned merchant plants.
• Specific Plant Turbine and Emissions Control Descriptions
are provided below.
Facility
Redding
Sutter
Delta
LMEC
Turbine Type (Number)
Alstom GTX100 (1)
Westinghouse 501FD (2)
Westinghouse 501FD (3)
General Electric 207FA (2)
MW (Turbine/Plant)
43/56 (Unit 5 only)
175/540
175/861
172/555
Emission Control Technologies
SCONOx
DLN, SCR, and Oxidation Catalyst
DLN, SCR
DLN, SCR, and Oxidation Catalyst
CALIFORNIA ENERGY COMMISSION
Power Plant Data
Ammonia Flow
Process Status
Uncontrolled NOx
Controlled NOx
Controlled CO
Oxygen Content
X
X
X
X
X
X
X
X
X
N/A
X
X
X
X
X
-
X
X
-
X
X
X
X
X
X
X
X
X
X
X
X
X2
X2
SCR Catalyst
Temperature
Efficiency Est.
-
Turbine/Stack Exhaust
Temperatures
MW Output (GT only)
-1
X2
X2
Exhaust Data
Heat or Fuel Input
X
X
X
X
Performance Data
Pipeline Gas Inert
Composition
Pipeline Gas
Hydrocarbon
Composition
Facility
Redding
Sutter
LMEC
Delta
Btu Content (as used)
Natural Gas Data
-/- N/A
X/X X
X/X/-
1 – Data supplied includes blended gas composition data.
2 – Data supplied from PG&E pipeline adjacent to Delta gas blending facility, but blended gas
composition data for Delta was not supplied.
CALIFORNIA ENERGY COMMISSION
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
0:00:00
4:00:00
8:00:00
12:00:00
16:00:00
20:00:00
• Sutter Turbines
Heat Input Rate (MMBtu/hr)
9-Jun-05
9-Jun-05
10-Jun-05
10-Jun-05
11-Jun-05
11-Jun-05
12-Jun-05
13-Jun-05
12-Jun-05
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
20:00:00
16:00:00
12:00:00
8:00:00
4:00:00
0:00:00
• Redding Turbine
MMBtu/hr
Gas Turbine Load Variability
425
400
375
350
325
300
13-Jun-05
2000
1800
1600
1400
1200
1000
CT1
800
CT2
600
400
200
0
14-Jun-05
CALIFORNIA ENERGY COMMISSION
Uncontrolled NOx Emissions vs. Heat Content
Sutter Turbine 2
Redding
28
30
Uncontrolled NOx PPM
Uncontrolled NOx PPM
28
26
24
27
26
22
25
20
970
980
1030
1020
1010
1000
990
Natural Gas Heat Content (Btu/scf)
1040
1050
1020
1030
1040
1050
Natural Gas Heat Content (Btu/scf)
1060
CALIFORNIA ENERGY COMMISSION
Ammonia Consumption vs Heat Content
110
Sutter Turbine 2
ammonia injection
rate vs. natural gas
heat content at near
similar operating
loads
Ammonia Injection Rate (lbs/hour)
105
100
95
90
85
80
75
70
975 980 985 990 995 1000 1005 1010 1015 1020 1025 1030 1035
Natural Gas Heat Content (Btu/scf)
CALIFORNIA ENERGY COMMISSION
Controlled NOx Emissions vs. Heat Content
0.44
0.43
Redding Controlled NOx
Controlled NOx PPM
0.42
0.41
0.40
0.39
0.38
0.37
0.36
0.35
0.34
1020
1025
1030
1035
1040
1045
1050
1055
1060
Natural Gas Heat Content (Btu/scf)
2.4
Sutter Controlled NOx
NOx Emissions PPM
2.3
2.2
Turbine 1
Turbine 2
2.1
2
1.9
1.8
980
990
1000
1010
1020
1030
1040
Natural Gas Heat Content (Btu/scf)
CALIFORNIA ENERGY COMMISSION
Conclusions
• Results of this study may not apply to all newer combined
cycle gas turbine facilities; particularly different turbine
models/makes and those with different combustors.
• Additional data from other combined cycle plants,
including any 7F turbine base load plants, should be
collected when similar natural gas heat content excursion
events occur.
• Additional data from simple cycle plants should be
collected.
• Additional data from other older facilities that make up
the bulk of the current natural gas fired power plant
emissions (i.e. cogeneration units, perhaps even steam
boilers).
• Additional data should include gas specific density for
the as used turbine fuel so that comparisons with Wobbe
number can be made.
CALIFORNIA ENERGY COMMISSION