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1 Experience with IR 70kW installations on LFG, will current emission performance be enough? January...

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1 Experience with IR 70kW installations on LFG, will current emission performance be enough? January 26, 2005
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1

Experience with IR 70kW installations on LFG, will current emissionperformance be enough?

January 26, 2005

2

Example Landfill Characteristics

• Small, closed municipal solid waste landfill• Located in Southern California• 1.8M tons of waste over 18 years• Owned / operated by local county authority• No operator on-site

3

Landfill Gas Collection

• 40 vertical extraction wells• 7,000 feet of 4 to 10 inch gas collection

piping• 3 condensate pumps• 2,400 gallon condensate storage tank• 2 - 800 scfm gas extraction blowers• 800 scfm enclosed flare with condensate

injectionPierce, Benson, SCS Energy

4

Landfill Gas Condition

• Methane content typically 33% to 40%

• Up to 10% swings per day• Has been measured as low as

28%• On-site fuel conditioning system• Removes water and

contaminants, compresses landfill gas

• Siloxane removal for 2 microturbines only

5

Microturbines in Facility

• 4 – 70kW microturbines• Sized to consume 100% of gas• Commissioned March 2002• On-site continuous methane

analyzer and calibration gases• Microturbines start-inhibited

under low methane conditions• Microturbines operate as a group

(sequential startup)

6

Microturbine Power Production

• 24/7 electricity (baseload) mostly exported to the grid• Site equipment only consumes 5% of power• $250/kW grant from CEC• Five year, fixed price PPA at $0.06/kWh with local utility• 64,376 hours through December 2004• About 1,500,000 to 1,750,000 kWh electrical output per

year

7

Microturbine Annual Run History

0

20

40

60

80

100

120

12

/29

/20

03

1/1

2/2

00

4

1/2

6/2

00

4

2/9

/20

04

2/2

3/2

00

4

3/8

/20

04

3/2

2/2

00

4

4/5

/20

04

4/1

9/2

00

4

5/3

/20

04

5/1

7/2

00

4

5/3

1/2

00

4

6/1

4/2

00

4

6/2

8/2

00

4

7/1

2/2

00

4

7/2

6/2

00

4

8/9

/20

04

8/2

3/2

00

4

9/6

/20

04

9/2

0/2

00

4

10

/4/2

00

4

10

/18

/20

04

11/1

/20

04

11/1

5/2

00

4

11/2

9/2

00

4

12

/13

/20

04

12

/27

/20

04

1/1

0/2

00

5

kW

or

De

gF

Power Output

Inlet Air Temperature

8

Operating Experience

• Fuel composition has become more stable• Low methane start-inhibit improves facility

control • Siloxane levels appear to be low• Enclosure working well, no corrosion,

minimal dust• Ambient temperatures range from about

100°F midday summer to 30’s in the night• Converted MTs from internal fuel gas

boosters to high pressure fuel valves to handle wind-driven ambient temperature variations

9

Fuel Analyses of Various LFG Sites

• Wide variety in constituent volumes• CO2 and N2 composition affects adiabatic flame temperature• Which in turn controls key chemical reactions: NOx formation and CO

destruction

CO2 N2

%vol %vol MJ/m3 Btu/ft3

LFG 1 49.00 20.30 10.06 270.05LFG 2 48.80 18.10 10.97 294.47LFG 3 27.90 38.30 11.11 298.23LFG 4 28.70 29.80 13.72 368.29LFG 5 34.80 18.00 15.99 429.20LFG 6 22.20 23.10 15.46 414.90Digester Gas 36.80 1.30 20.63 553.78

LHVApplication Type

10

Fundamental Engine Emission Limits

• Thermal NOx formation significant above 1850°K

• CO occurrence increases at lower temperatures– Lower reaction rates– Less oxidation

• Result is a narrow temperature regime to realize both low NOx and low CO

Rokke, Hustad, Rokke, Svendsgaard, ASME GT2003-38112

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1500 1600 1700 1800 1900 2000 2100

Gas Temperature

CO

(m

g/g

)

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

0.2

NO

x (m

g/g

)

11

Microturbine Emissions Using LFG

• Microturbines represent a clean method of eliminating LFG that generally meets today’s non-attainment area permitting limits for “waste gases”

• Typical district NOx and CO permitting limits around 9 to 15 ppm @15% O2

• California ARB-released source testing results:

LHV Btu/ft3

Location Test MethodNOx ppm @15% (lb/MWh)

CO ppm @15% (lb/MWh)

VOC ppm @15% (lb/MWh)

I-R 70LM 534 Toland Road Landfill EPA 7E, 10, 25c 1 (0.07) 2 (0.07) 5* (0.16)

Capstone 330 417 Calabasa Landfill SCAQMD 25.1, 100.1 3 12 2.4*

California ARB, DG Technical Review, 2005-01-03

12

Natural Gas Emissions Limits In California

• By default, MTs are permitted in California unless they meet certain exceptions– fueled by natural gas and– below a certain size threshold and– not located in a “sensitive” area.

• If not permitted, must be certified by CARB

(100% Load Conditions Only)NOx CO VOC NOx CO VOC NOx CO VOC

MT 10.93 216 62.70 0.50 6.00 1.00 0.169 2.029 0.338

MT 3.06 N/A N/A 0.14 N/A N/A 0.047 N/A N/A

MT 1.53 3.60 1.23 0.07 0.10 0.02 0.024 0.034 0.007

MT 9.00 9.00 9.00 0.41 0.25 0.14 0.139 0.085 0.048 MT 9.00 10.00 9.00 0.41 0.28 0.14 0.139 0.094 0.048 MT 1.53 3.60 1.23 0.07 0.10 0.02 0.024 0.034 0.007 MT 42.00 N/A N/A 1.92 N/A N/A 0.649 N/A N/A

MT 9.00 10.00 5.00 0.41 0.28 0.08 0.139 0.094 0.026

MT 5.00

or 9.00 10.00 5.00

0.23 or 0.41

0.28 0.08 0.07

or 0.14 0.094 0.026

SJVAPCD (San Joaquin) - Current

BAAQMD (Bay Area) - Current 10/15/04

SCAQMD (South Coast) - Current "Typical" Permit Limits

SDAPCD (San Diego) - Current 10/15/04

g/bhp-hr

AB1685-2003 SGIP 2005 Required LimitCARB SB1298-2000 Certification2007 Limits

SCAQMD (South Coast) - Proposed

lb/MW-hrppm @15% O2

CARB SB1298-2000 Certfication2003 Limits

13

Future Emissions Limitations

• Trend in non-attainment regions:– Lower Distributed Generation (DG) emissions to

“Central Plant BACT” (CARB 2007) levels• NOx at 0.07 lb/MWh• CO at 0.10 lb/MWh• VOCs at 0.02 lb/MWh

– January 1, 2007 (if not earlier) in California– Natural gas-fueled DG

• Over a longer period (2012 to 2015?), force “waste fuels” emissions to Central Plant BACT levels as well

14

Future Microturbine Emissions

• Meeting 2007 BACT limits will be a challenge for microturbines

• In natural gas applications microturbines can claim CHP credits– Example: 3.1413 MMBtu of recovered heat

equivalent to 1 MWh of output– Credits act to “lower” criteria emissions results when

compared to limits

• However, no equivalent credit exists for “waste fuels” DG emissions

• Credit for displaced LFG flare emissions?


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