GAS QUALITY: HOW IT IMPACTS QUESTAR GAS
Docket 04-057-09October 13, 2004
NATURAL GAS
AIR
HEAT + H20 + CO2 + CO + Other Stuff
Try to keep as high as possibleTry to keep as low as possible
Orifice size adjusted for specificinstallation conditions:- Altitude- Gas Composition
COMBUSTION THEORY 101
• Efficient and safe combustion requiresthe correct ratio of oxygen and fuel
• The ability of an appliance to properly combusta fuel different than what it was adjusted fordepends on the heating value and specificgravity of the fuel
Specific Gravity
Heating ValueWobbe Number =
1060 Btu/CF & .61 S.G.(Wobbe # 1357)
AIR
Appliance Properly Adjusted for Altitude and 1088 Btu/CF & .62 Specific Gravity (Wobbe # 1382)
IMPACT OF GAS QUALITY CHANGE ON APPLIANCE PERFORMANCE
Case 1: Ideal Conditions
• Proper flame characteristics• Appliance will perform as rated• Low carbon monoxide emissions
NATURAL GAS
985 Btu/CF & .575 S.G.(Wobbe # 1299)
AIR
Appliance Properly Adjusted for Altitude and 1088 Btu/CF & .62 Specific Gravity Gas (Wobbe # 1382)
IMPACT OF GAS QUALITY CHANGE ON APPLIANCE PERFORMANCE
Case 2: Introduction of Coal Seam Gas
•Flame instability (liftoff and possible blow-off)•Appliance will produce less heat than rated•Increase in carbon monoxide emissions
NATURAL GAS
985 Btu/CF & .575 S.G.(Wobbe #1329)
AIR
Appliance Properly Adjusted for Altitude and 1003 Btu/CF & .56 Specific Gravity Gas (Wobbe #1340)
IMPACT OF GAS QUALITY CHANGE ON APPLIANCE PERFORMANCE
Case 3: Re-Orifice Appliance Southern System Set-Point
•Proper flame characteristics•Appliance will perform as rated•Low carbon monoxide emissions
NATURAL GAS
Change orifice out with larger diameter orifice
Approximate Interchangeability Ranges
960 980 1000 1020 1040 1060 1080 1100
BTU
UINTA
PICEANCE
SAN J UAN
POWDER RIVER
Denver
GREEN RIVER
FERRON
1975 Salt Lake City
- Legend -
Other Pipelines in the Interstate Grid
Producing Basins
Questar Pipeline System
Northwest
CIG
El Paso
Transwestern
UINTA
PICEANCE
SAN J UAN
POWDER RIVER
Denver
GREEN RIVER
1998 Salt Lake City
FERRON
- Legend -
Other Pipelines in the Interstate Grid
Producing Basins
Questar Pipeline System
Northwest
CIG
El Paso
Transwestern
UINTA
PICEANCE
SAN J UAN
POWDER RIVER
Denver
GREEN RIVER
FERRON
Main Line 104 (2001)
Current
Kern River Loop (2003)
Salt Lake City
- Legend -
Other Pipelines in the Interstate Grid
Producing Basins
Questar Pipeline System
New Pipelines after 1998
Northwest
CIG
El Paso
Transwestern
PIPELINE BTU SPECIFICATIONS(September, 2004)
PIPELINE COMPANY MINIMUM BTU MAXIMUM BTU
ANR 967 1200
CIG 968 1235
Columbia Gulf 978 None
El Paso Natural Gas 967 None
Florida Gas Transmission 1000 None
NGPL 950 None
Northern Border 967 None
Northwest Pipeline 985 None
Panhandle Energy 950 1200
Sonat 950 None
Kern River 970 None
Tennessee 967 1100
Texas Eastern 967 None
Trailblazer 950 None
Transco 980 1100
TransWestern 970 None
Trunkline 950 1200
Questar 950 1150
Questar Pipeline – Downstream Btu Delivery Specs.
KRGT (Goshen)
Min. – 970 Btu/CFMax.– No Limit Btu/CF
QGC (Payson)
Min. - 950 Btu/CfMax. – 1150 Btu/CF
KRGT (Roberson Creek)Min. - 970 Btu/CF
Max.– No Limit Btu/CF
TransColoradoMin.- 967 Btu/Cf
Max.- No Limit Btu/CF
Southern StarBtu Delivery Requirements
Min.– 970Max.– No Limit
NPC (XO-16)
Min. - 985 Btu/CFMax. – No Limit
QGC (Northern Wasatch Front)
Min. - 950 Btu/CFMax.– 1150 Btu/CF
NPC (Clay Basin)
Min. - 985 Btu/CFMax. – No Limit
Kanda
FidlarPrice
ML 40/41
ML 104
ML 40
ML 68
ML’s 1/13/15
ML
80M
L58/
101
ML 22
Greasewood
Legend:
OakSpring
Eakin
Davis Plant - 3rd Party
JL 47
Overthrust Pipeline
Compressor Station
Delivery Point
CO2Plant
CIGMin.– 968 Btu/CF
Max.– 1235 Btu/CFWIC
Min.– 950 Btu/CFMax. –No Limit
Natural Gas Producers
Questar Pipeline Tariff Min.- 950 Btu/CF
Max.- 1150 Btu/CF
Basin Map
C
M
M TCGTFIDLAR
MCIG
NATURALBUTTES
CRMNG
RIFLE
REDWASH
M.L
.80
S
CLAYBASIN
CRAIG
C
DRIPPINGROCK
STATELINE
M SKULLCREEK
C
SIMON
M
HAYSTACK
WGPC
C NIGHTINGALE
M.L
.58
NPC
C
M
MM OT
MMUDDY CREEK
WHITNEYCANYON
OT
J.. L
36
KRGT
SLEROY EAKIN
M.L. 1,1
3,15
CIGWIC
M.L.40
C
OAK SPRING
M
M
M
M
M
MM INDIANOLAQGCNEPHI
CITY
PAYSON GATE
S CHALK CREEKS
COALVILLE
LITTLEMOUNTAIN
PORTERS LANE
SUNSET GATE
HYRUM GATE
QGC
QGC
QGC
QGC
QGC
KR
GT
IDAHO WYOMING
UTAH
COLORADO
NPC
NPC
SOUTH LAKE
MC
KANDA/COLEMAN
PRICE
M
M DRAGON TRAIL
NPC
XO-16
C
CO2 PLTCM
ELBERTA
M
Piceance Basin
Uinta Basin
Ferron
East Fields
Green River Basin
Overthrust
Questar Pipeline – Gas Quality Distribution
KRGT (Goshen)
Min. – 970 Btu/CFMax.– No Limit Btu/CF
QGC (Payson)
Min. - 950 Btu/CfMax. – 1150 Btu/CF
KRGT (Roberson Creek)
TransColorado
Southern Star
QGC (Northern Wasatch Front)
Min. - 950 Btu/CFMax.– 1150 Btu/CF
NPC (Clay Basin)
Kanda
FidlarPrice
ML 40/41
ML 104
ML 40 ML 68
ML’s 1/13/15
ML
80M
L58/
101
ML 22
Greasewood
OakSpring
Eakin
Davis Plant - 3rd Party
JL 47
Overthrust Pipeline
CO2Plant
CIGWIC
East Fields
Max. Btu-1150Min. Btu-950
Green River BasinMax. Btu-1176Min. Btu-1025
Overthrust
Max. Btu-1170Min. Btu-1000
FerronMax. Btu-1060Min. Btu-984
Uinta BasinMax. Btu-1150Min. Btu-1020
Piceance BasinMax. Btu-1200Min. Btu-1020
Historical Basin Heating Value
900
950
1,000
1,050
1,100
1,150
1,200
1,250
Jan-
97
May
-97
Sep-
97
Jan-
98
May
-98
Sep-
98
Jan-
99
May
-99
Sep-
99
Jan-
00
May
-00
Sep-
00
Jan-
01
May
-01
Sep-
01
Jan-
02
May
-02
Sep-
02
Jan-
03
May
-03
Sep-
03
Jan-
04
Date
Cal
orifi
c V
alue
, Btu
per
cub
ic fo
ot
Piceance
Uinta Basin
East Fields
Green River
Overthrust
Ferron
Updated on: May 5,2004
Historical Basin Daily Volume
-
50
100
150
200
250
300
Jan-
97
Apr-
97
Jul-9
7
Oct
-97
Jan-
98
Apr-
98
Jul-9
8
Oct
-98
Jan-
99
Apr-
99
Jul-9
9
Oct
-99
Jan-
00
Apr-
00
Jul-0
0
Oct
-00
Jan-
01
Apr-
01
Jul-0
1
Oct
-01
Jan-
02
Apr-
02
Jul-0
2
Oct
-02
Jan-
03
Apr-
03
Jul-0
3
Oct
-03
Jan-
04
Apr-
04
Date
Vol
ume
, MM
cfd
Piceance
Uinta Basin
East Fields
Green River
Overthrust
Ferron
Updated on: May 5,2004
PRICE AREA COAL BEDPRODUCTION HISTORY
0
50,000
100,000
150,000
200,000
250,000
300,000
Th
ousa
nd
Cu
bic
Fee
t p
er D
ay
1993
1995
1997
1999
2001
2003
YEAR
TYPES OF NATURAL GAS
Traditional Supplies 970 – 1250• Associated Gas • Dry Gas • Sour Gas
Current/Future Supplies• Coal Seam Gas 970 - 1030• LNG 1040 - 1200 Manufactured Gas 500 – 1000• Coal Gasification • Landfill/Biomass
Supply Source
Btu Range
WOBBE - INDEXIts Importance to Gas Interchangeability
• Wobbe Number – Relationship between the heating Value and Specific Gravity, defined as
• Wobbe Number is a good first-order predictor of appliance performance relative to a base or adjustment gas
• Wobbe Number is used throughout the world as the most common interchangeability metric
• Gas is generally considered interchangeable when the Wobbe number lies within a +/- 5% tolerance band around a set-point
Specific Gravity
Heating ValueWobbe Number =
Gas CompositionCoal Seam Gas
984
0.588
96.4%
0.27%
0.0543%
0.0139%
0.0018%
2.5%
-110.5°
0.18%
1283
Uinta Basin Gas1115
0.632
90.7%
5.06%
1.95%
0.863%
0.5923%
0.629%
70.4°
0.24%
1402
Representative BtuSpecific GravityPercent Methane(1010 Btu/Scf) Percent Ethane(1789 Btu/Scf)Percent Propane(2516 Btu/Scf)Percent Butane(3250 Btu/Scf)Percent C5+(5500+ Btu/Scf)Percent Inerts(CO2, etc.)Hydrocarbon DewpointPercent NitrogenWobbe (W = HV/G)
Northern Gates Gas1070
0.616
92.0%
4.35%
1.20%
0.491%
0.315%
0.629%
40.9°
0.48%
1363
Approximate Interchangeability Ranges
960 980 1000 1020 1040 1060 1080 1100
BTU
Btu Ranges for Area Production
900 1000 1100 1200
Piceance Fields
Uinta Basin
East Fields
Green River
Overthrust
Coal Seam Gas
Questar Gas Interchangeablity
10
20
Btu
10
60
Btu
Questar Gas Btu Delivery Ranges(1995 – Present)
900
920
940
960
980
1000
1020
1040
1060
1080
1100
8/3
0/1
995
12/3
0/1
99
5
4/3
0/1
996
8/3
0/1
996
12/3
0/1
99
6
4/3
0/1
997
8/3
0/1
997
12/3
0/1
99
7
4/3
0/1
998
8/3
0/1
998
12/3
0/1
99
8
4/3
0/1
999
8/3
0/1
999
12/3
0/1
99
9
4/3
0/2
000
8/3
0/2
000
12/3
0/2
00
0
4/3
0/2
001
8/3
0/2
001
12/3
0/2
00
1
4/3
0/2
002
8/3
0/2
002
12/3
0/2
00
2
4/3
0/2
003
8/3
0/2
003
12/3
0/2
00
3
4/3
0/2
004
8/3
0/2
004
Date
Btu
Hyrum Gate Station Btu
Little Mountain Gate Station Btu
Payson Gate Station Btu
Kern Gas Quality to QGC
1000
1010
1020
1030
1040
1050
1060
1070
Nov-9
9
Jan-
00
Mar
-00
May
-00
Jul-0
0
Sep-0
0
Nov-0
0
Jan-
01
Mar
-01
May
-01
Jul-0
1
Sep-0
1
Nov-0
1
Jan-
02
Mar
-02
May
-02
Jul-0
2
Sep-0
2
Nov-0
2
Jan-
03
Mar
-03
May
-03
Jul-0
3
Sep-0
3
Nov-0
3
Jan-
04
Mar
-04
May
-04
Jul-0
4
Sep-0
4
Date
BT
U
Kern BTU Southern Kern Northern Kern
ML #104
10
00
11
00
10
50
Btu/SCF
1003
QG
C S
OU
TH
PO
ST
-199
8
1088
Pre
-199
8 B
ase
Gas
1048
1006
1023
QG
C N
OR
TH
PO
ST
199
8
QGC BTU SET-POINTS RELATIVE TO BTU OF GAS DELIVERED TO 26 MAJOR URBAN AREAS1/
National LDC Btu Range
Encompasses 90% of Data
1/”Variability of Natural Gas Composition in Select Major Metropolitan Areas of the United States,” preparedby the American Gas Association Laboratories for Gas Research Institute, GRI-92/0123, March 1992
Questar Gas Position Points
1. An improperly adjusted appliance creates a safety hazard.
2. QGC and QPC constantly manage heat content and other gas quality criteria for safe, reliable use.
3. Post FERC regulations, Rocky Mountain pipelines have adopted national interstate grid gas quality specifications.
4. QGC’s gas sources (QPC & Kern River), as part of the interstate pipeline grid, supply volumes whose gas quality is aligned to the national market.
5. Markets, beyond the Rocky Mountains, have a major influence on
gas quality and the physical flows of Rocky Mountain production.
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