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LNG Interchangeability––Residential Field Studies and Sensitive Industrial Burner Tests
> Neil Leslie - presenter R&D Director, End Use Solutions Gas Technology Institute
> International Gas Union Research Conference 19 September 2014
IGRC 2014 2 IGRC 2014 2
Interchangeability Defined
> The ability to substitute one gaseous fuel for another in a combustion application without materially changing operational safety or performance and without materially increasing air pollutant emissions
Source – NGC+ Working Group on Interchangeability White Paper presented to FERC, Feb. 2005
IGRC 2014 3 IGRC 2014 3
Program Objective
> To provide information to policymakers, regulators and industry such as on the potential safety, performance and air quality impacts of increased variability in the California natural gas supply, and specifically related to the use of LNG
> Combustion systems studied include: ─ Industrial combustion systems ─ Commercial cooking appliances ─ Residential appliances
IGRC 2014 4 IGRC 2014 4
Industrial Burner and Cooking Appliance Test Gases > Adjust gases
are California natural gas average compositions
> Substitute gases are representative Pacific Basin LNG compositions
Adjust 1
Adjust 2
Adjust 3
Substitute 1
+ 1.3 %N2
+ 2.1 %N2
+ 5.0 %N2
+ 6.3 %N2
+7.8% N2
+6.4% N2
+3.1 %N2
+2.4 %N2
Substitute 2
California limit, 1385
1300
1320
1340
1360
1380
1400
1420
1440
1000 1020 1040 1060 1080 1100 1120 1140
HHV (Btu/scf)
Wob
be N
umbe
r
IGRC 2014 5 IGRC 2014 5
Organizing the Many Industrial Burners
Operating Characteristics Types and Applications Mixing method Radiant Burners
Fuel High Velocity Burners
Oxidant (air, O2, etc.) Regenerative Burners
Draft type Natural Draft Burners
Heating type Boiler Burners
Burner Geometry Linear Grid/In-Duct Burners
O2 and O2-Enriched Air Burners
Flare Burners
IGRC 2014 6 IGRC 2014 6
Burner Classes and Sensitivity
IGRC 2014 7 IGRC 2014 7
Burners Selected for Testing
Manufacturer Model Name
Comment
Control
Capacity, MMBtu/hr
Radiant Burners
North American Evenglow Radiant Tube Modulating +Pressure Balance 0.02-0.5
Maxon Radmax Radiant Panel On/Off + Venturi mixer 0.025 per head
Bloom Engineering 2320 Recuperative Modulating 0.4 - 0.5
Boiler Burners
Powerflame C1-G-12 Turndown 10:1 Cam linkage + O2 Trim 2-14.7
Cleaver-Brooks SB-200-080-150 Low NOx Packaged System 80HP
LAARS Mighty Term II Hydronic Boiler Staged Control 0.5 – 2.0
Linear/Grid/Duct Burners
Flynn Burner Pipe Linear Burner (baking) Modulating +Venturi mixer 0.04 per inch
Oxygen Enhanced Combustion
Eclipse PrimeFire 300 High Luminosity On/Off + Pressure Balance 0.5 – 8.0
Regenerative Burners
Bloom Engineering 1150 Nozzle-Mixed type Modulating +Pressure Balance To be tested
Nozzle Mixed Burners
Eclipse Combustion ThermJet High Velocity Modulating +Pressure Balance 0.15 - 20
All relevant types are covered; top sellers–by market presence
Lab Testing
Field Testing
IGRC 2014 8 IGRC 2014 8
Emissions for Industrial Burners
> Burners tuned to Adjust Gas 2 at 1332 Wobbe, then fired with different adjust and substitute gases
> Emissions vary widely and changes in emissions with Wobbe differ between different burners
0
300
600
900
1200
1500
1800
2100
2400
2700
3000
0
20
40
60
80
100
120
140
160
180
200
1280 1300 1320 1340 1360 1380 1400 1420 1440
NO
x (p
pm) (
corre
cted
to 3
% O
2) [O
xy-G
as]
NO
x (p
pm) (
corre
cted
to 3
% O
2)
Wobbe
Adjust2 Basis
Infrared
Linear
High Velocity
Oxy-Gas
1385 Limit
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
2750
3000
0
5
10
15
20
25
30
35
40
45
50
55
60
1280 1300 1320 1340 1360 1380 1400 1420 1440
CO
(ppm
) (co
rrect
ed to
3%
O2)
[HV,
OG
]
CO
(ppm
) (co
rrect
ed to
3%
O2)
Wobbe
Adjust2 Basis
Infrared
Linear
High Velocity
Oxy-Gas
1385 Limit
IGRC 2014 9 IGRC 2014 9
Emissions for Boiler Burners
> Burners tuned to Adjust Gas 2 at 1332 Wobbe, then fired with different adjust and substitute gases
> NOx varies widely based on burner type
> CO is low for all boiler burners and decreases at higher Wobbe
0
5
10
15
20
25
30
35
40
45
50
55
60
1280 1300 1320 1340 1360 1380 1400 1420 1440
NO
x (p
pm) (
corre
cted
to 3
% O
2)
Wobbe
Adjust2 BasisPackagedBoilerBoiler (Field)1385 Limit
0
5
10
15
20
25
1280 1300 1320 1340 1360 1380 1400 1420 1440
CO
(ppm
) (co
rrect
ed to
3%
O2)
Wobbe
Adjust2 BasisPackagedBoilerBoiler (Field)1385 Limit
IGRC 2014 10 IGRC 2014 10
Emissions for Radiant Tube Burners
> Burners tuned to Adjust Gas 2 at 1332 Wobbe, then fired with different adjust and substitute gases
> NOx varies widely and decreases with higher Wobbe
> CO can increase exponentially at low excess air levels
0
20
40
60
80
100
120
140
160
180
200
1280 1300 1320 1340 1360 1380 1400 1420 1440
NO
x (p
pm) (
corre
cted
to 3
% O
2)
Wobbe
Adjust2 BasisU-TubeW-Tube (Field)1385 Limit
0
250
500
750
1000
1250
1500
1750
2000
2250
2500
2750
3000
0
1
2
3
4
5
6
7
8
9
10
11
12
1280 1300 1320 1340 1360 1380 1400 1420 1440
CO
(ppm
) (co
rrect
ed to
3%
O2)
[U-T
ube]
CO
(ppm
) (co
rrect
ed to
3%
O2)
Wobbe
Adjust2 BasisW-Tube (Field)U-Tube1385 Limit
IGRC 2014 11 IGRC 2014 11
Conclusions: Industrial Burners
> No industrial burners had ignition problems over the range of gases studied (1308-1425 W)
> Emissions (NOx, CO) can increase, decrease, or be unchanged for burners
> With proper tuning NOx for all burners at 1385 W can be equal to or lower than NOx when burner is tuned to 1332 W
> For burners using low oxidant to fuel ratios (radiant tubes, oxygen burners, low NOx boilers) higher W gas requires increased oxidant to avoid exponential increases in CO
> Many burners require no adjustments for NOx, CO
> Advanced controls can do needed tuning for many burners
> Data suggests simplified protocols can be devised for the remaining burners of concern
IGRC 2014 12 IGRC 2014 12
Commercial Cooking Unit Selection
> GTI enlisted Carl Suchovsky, President of Gas Consultants, Inc. and Don Fisher of Fisher-Nickel, Inc. to help select the commercial foodservice appliances
> Selected appliances were representative of equipment currently sold in California
> Appliances represented technology commonly found in restaurants
> Choices covered the burner types found in food service equipment (atmospheric, infrared, powered and fan-assisted burners)
IGRC 2014 13 IGRC 2014 13
Commercial Cooking Appliances Selected
Appliance Manufacturer Model Notes
Fryer Frymaster FH155 Infrared burner, exhaust fan
Fryer Pitco SG-14 or SSH55 Atmospheric burner
Convection Oven
Blodgett DFG-100Xcel Atmospheric burner, exhaust blower
Combi Oven Cleveland OGB-6.20 Dual premixed powered burners
Griddle Vulcan 36RRG Atmospheric U-shaped burners
Griddle Jade JSO315 Blue flame burner (cast iron open burners)
Range Garland G36-6R 33,000 Btu/h top burner
Steamer AccumTemp N6 Stainless steel powered burner
IGRC 2014 14 IGRC 2014 14
Appliance Test Facility
IGRC 2014 15 IGRC 2014 15
CO in Flue Over Wobbe Range of Gases
0
100
200
300
400
500
600
700
800
Mea
sure
d CO
in F
lue
Gas
, pp
mWobbe - 1309 Wobbe - 1385
IGRC 2014 16 IGRC 2014 16
NOx in Flue Over Wobbe Range of Gases
0
20
40
60
80
100
120
140
160
Mea
srue
d N
Ox
in F
lue
Gas,
ppm
Wobbe - 1309 Wobbe - 1385
IGRC 2014 17 IGRC 2014 17
Food Service Appliance Summary
> No issues with ignition or operation of equipment tested
> Based on NOx and CO emissions appliances can have none, some, or significant interchangeability concerns
─ Some minor concerns with NOx at high Wobbe ─ CO rises to high levels for some appliances at high
Wobbe > Testing of excess O2 in the flue is a good indicator of
high CO and an appliance needing adjustment > Appliances must be either adjusted by manufacturer
or by trained service technician for low emission operation with high Wobbe gas
IGRC 2014 18 IGRC 2014 18
Appliance Burner Experiments
> Cooking: 13 cooktops, 12 ovens, 5 broilers > Vented: 5 storage water heaters, 6 tankless , 5 furnaces > Fuels:
─ Northern CA line gas: 1330-1340 WN ─ Simulated LNG: 1390, 1420 WN (some 1360 WN)
> Experimental Approach: ─ Operating cycles to capture transient emission events ─ Duplicate burns for cooktops, ovens, furnaces, storage WHs ─ Varied operation for oven (temp) and tankless (flow) ─ Calculated emission factors for full-burn, end-of-burn ─ Univariate: emissions by burner and fuel ─ Bivariate: emissions related to fuel WN ─ Multivariate: included other effects ─ Changes in emission factor were related to increase in Wobbe Number
IGRC 2014 19 IGRC 2014 19
Example Data From Cooktop Experiment
> Pot + 4 L H2O on each corner burner, all at highest firing rates; 15 minute burns
> Cooling period varied in early experiments, then consistent at 15 minutes (CT02, fuel 3A+N2)
IGRC 2014 20 IGRC 2014 20
Example Data From Oven Experiment
> Subsequent experiments used 2-3 maintenance cycles per T setting (OV02, fuel 3A)
350 F 425 F 500 F
IGRC 2014 21 IGRC 2014 21
Interpretation of Results
Cooking/Unvented Burners
> Indoor exposures > Concern: impacts for individual
burners > Focus on primary pollutants
─ CO, NO2, PN, HCHO ─ Small contribution to ambient air
quality
> Sample includes common technologies, varied ages
> Sample not large enough to reliably assess outliers
Vented Burners
> Ambient air quality > Concern: impacts on total
emissions from population > Focus on regulated pollutants
─ NOX effect on O3, PM2.5
─ CO small effect on ozone ─ HCHO is Hazardous Air Pollutant ─ NO2 primary pollutant
> Most common technologies sampled; results consistent with other studies
IGRC 2014 22 IGRC 2014 22
Baseline Emissions* by Appliance Group
CO
(ng J-1)
NO2
(ng J-1)
HCHO
(ng J-1)
PN*
(104 J-1)
NOX
(ng J-1)
Cooktops 7 – 823 5.0 – 17.7 0.1 – 4.7 183 – 9200 25 – 47
Ovens 16 – 528 3.8 – 13.9 0.3 – 5.5 10 – 6300 27 – 41
Broilers 29 – 178 2.8 – 13.0 0.1 – 0.9 107 – 2650 17 – 37
Furnaces <1 – 31 <1 – 9.7 0.2 , 0.4 <1 – 46 22 – 34
Storage WH <0 – 2 0.3 – 2.2 <0.1 3 – 51 24 – 32
Tankless WH 19 – 434 4.0 – 8.9 0.2 – 2.4 <1 – 27 9 – 31
* Range of mean emissions across burners; PN is range of maxima across burners.
IGRC 2014 23 IGRC 2014 23
Key Findings: Cooktops
> CO: Increases in most cooktops ─ Significant increases in 11 of 13 cooktops ─ ↑6-40% for 4 cooktops with CO > 100 ng/J
> NO2: Increases in half of the cooktops ─ Significant increases in 7 of 13 cooktops;
↑5-20% ─ All had NO2 > 5 ng/J
> HCHO: Important impacts for some cooktops ─ No change for most burners including
highest emitter ─ Next two highest had one increase 62%,
one decrease 28%
> PN: varies much more with operation than fuel
Effects are change in emission factors (ng/J) per 50 Btu/scf increase in WN
IGRC 2014 24 IGRC 2014 24
Key Findings: Ovens and Broilers
> CO: Increases in most ─ Increases in 16 of 17 burners ─ ↑5-40% for 7 of 9 with CO ≥ 100 ng/J ─ ↓5-14% for 2 of 9 with CO ≥ 100 ng/J
> NO2: Increase in half of the burners ─ Increases in 9 burners: ↑10-38% for NO2 > 5 ng/J ─ Decrease of 7% in 1 burner
> HCHO: Some impacts ─ Increases of 8-20% in 6 burners; decrease of 21% in
1 burner ─ No change in 8; no data for 2 burners
> PN varies much more with operation than fuel
Effects are change in emission factors (ng/J) per 50 Btu/scf increase in WN
IGRC 2014 25 IGRC 2014 25
Key Findings: Water Heaters I
> Standard storage WHs have low CO and NO2, appear to have low HCHO; negligible fuel effects
> Tankless had higher CO, NO2, HCHO, PN
> Tankless: ─ CO increase for group dominated by unit
with bad regulator ─ Frequency of this problem in population is
unknown ─ NO2 ↑3-19% for 5 burners; ↓3% for 1 burner ─ HCHO ↓2-11% for 5 burners; no change for
1 burner
Effects are change in emission factors (ng/J) per 50 Btu/scf increase in WN
IGRC 2014 26 IGRC 2014 26
Key Findings: Water Heaters II
> Storage to tankless switch has much larger impact than LNG on CO, NO2, HCHO
─ Baseline emissions much higher ─ CO and NO2 increase with LNG ─ HCHO decreases with LNG (but higher than storage)
> Baseline NOX lower in tankless water heaters, but more sensitive to fuel WN
─ With LNG, NOX from tankless likely still lower than from conventional storage WHs
─ Given tankless NOX variability, need market analysis
> Effect of fuel WN on ultra-low-NOX storage WHs and next generation tankless?
─ TBD in CEC-funded Healthy Homes study
IGRC 2014 27 IGRC 2014 27
Key Findings: Furnaces
> CO: ─ Generally low emission rates ─ ↓26% in 2 furnaces, mixed or no change
in others
> NOX: ─ ↑3-7% in 3 furnaces, no change in other 2
> NO2: ─ ↓14% in 1 furnace; no change in others
> HCHO: ─ Data for only 2 of 5 furnaces tested ─ Relatively low baseline; ↓24-34% with
increasing fuel WN
Effects are change in emission factors (ng/J) per 50 Btu/scf increase in WN
IGRC 2014 28 IGRC 2014 28
Appliance Findings: Summary
> Appliance Operation ─ Consistent with other studies, we found no substantial
operational issues related to LNG use in residential appliances
> Pollutant Emissions ─ Small, if any increase in emissions from forced air
furnaces and storage water heaters ─ Tankless water heaters have higher emissions and LNG
impacts compared to storage WHs ─ Cooking burners can have substantial baseline
emissions and sensitivity to LNG
IGRC 2014 29 IGRC 2014 29
Connect With Us
Gas Technology Institute 1700 S Mount Prospect Rd, Des Plaines, IL 60018, USA www.gastechnology.org
Contact: David Rue Institute Engineer End Use Solutions
847-768-0508 david.rue@gastechnology.org
Authors: David Rue and Yaraslav Chudnovsky, PhD, GTI; Brett C. Singer, PhD, Lawrence Berkeley National Laboratory; Marla Mueller, California Energy Commission
@gastechnology
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