gaseous and particulate emissions from diesel generators dongzi zhu desert research institute
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Gaseous and Particulate Emissions from Diesel
Generators
Dongzi ZhuDongzi Zhu
Desert Research InstituteDesert Research Institute
Dirty Diesel engine Non-road Diesel engine (contrary to Onroad)DPM higher than onroad diesel engines (HDDTs)contributes 44% DPM, 12% of NOx from all mobile sources nationwide (EPA)exempt from fuel formulation (e.g. sulfur content) requirement, exhaust gas aftertreatment Non-road Diesel Mobile/stationary sources:construction, agriculture, locomotives, and marine vessels back-up generators, pumps, etc.
NAAQS Criteria pollutants: PM(2.5,10), NOx, SO2, CO, O3,Pb
Diesel generators large emitter of PM most < 1m, toxic air pollutantsNOx, precursor of O3
Hydrocarbon(HC), PAH carcinogens, precursor of SOA, O3
CO, SO2
Nationwide, 626,000 installed units of
diesel BUGs in 1996, estimated 1.7% annual
increase rate (740,941 units 2006)
11,000 diesel BUGs in California in
2000
Evidence indicates human health
hazards with exposure of diesel exhaust.
BUGs are close to school, hospitals,
municipal buildings, where human exposure
is high.
EPA regulated emission factors: NOx,
PM, CO, NMHC (and fuel sulfur content)
Tier 1 (1996-2000) (EPA,1994)
Tier 2 (2001-2006)
Tire 3 (2006-2008) (EPA,1998)
Tire 4 (2008-2015): PM, NOx reduced by
90% (EPA, 2004)
EPA AP 42 diesel generator (<440KW)
Emission Factors: NOx, PM,CO,CO2 THC,
(1996)
Population density and diesel BUGs location in L.A. region Population/mile2
0–20002000–60006000–10000> 10000
Tested 13 diesel
generators (10KW-100KW)
at Camp Pendleton, CA,
using DRI’s In-Plume
Emissions Testing System
Fuel analysis showed the
jerrycan fuel had different
properties than the fuels in
the generator tanks. 60KW
and 100KW tanks has JP-8
fuel.
Communications indicated
that the base was
temporarily unable to
obtain JP-8 fuel for the
generators and that were
using California #2 Diesel
to refuel the generators
when needed.
In-Plume Emissions Testing System (IPETS) diagram
PTFE/Quartz FiltersQuartz/K
2CO
3Filters
Quartz/Citric Acid FiltersNuclepore
Filters
TSI 40241 MassFlow Meters
TSI 40241 MassFlow Meters
Comtrol
8 port
RS232 to Ethernet
Gast PumpGast Pump Gast PumpGast Pump Gast PumpGast Pump
PM
2.5
Filter Module
INLET FROM SOURCE
TSI DustTrak PM10
Grimm 1.108 Coarse
Grimm 1.108 Fine
TSI ELPI
MIDAC FTIR
VacuumPump
VacuumPump
Gast PumpGast Pump
Q = 10 lpm
Q = 2.5 lpm
Q = 2.5 lpm
Q = 1.7 lpm
Comtrol 8 port RS232 to Ethernet
TSI 40241 MassFlow Meters
Field Computer
DAQ
EthernetHub
Q = 50 lpm
Comtrol
8 port
RS232 to Ethernet
TSI DustTrak PM2.5
Q = 1.7 lpm
Bendex
240
Cyclones
Mixing Plenum
Bendex
240
Cyclones
Mixing Plenum
Real Time PM Module Gas and DAQModule
Li-Cor CO2
Q = 1.0 lpm
Q = 113 L/m
LEGEND_____ Air Stream- - - -Data Stream
Li-Cor CO2
INLET FOR AMBIENT CO 2
Q = 1.0 lpm
PhotoAcoustic BCQ = 1.0 lpm
Fourier Transform Infra-Red spectrometer
• Beer-Lambert law: exponential attenuation 1/0 transmission spectrum T, fraction of radiation
reaching detector on y-axis with wavenumbers (equivalent to freq.) (1/cm) on the x-axis
log10(1/T) = A absorbance is absorption coefficient• C is concentration• L is the distance that the radiation travel through
the sample i 1=0 exp(-l)
lCA iii =
Source
radiation
Detector
Transmission spectrum and absorbance spectrum
The (sample) region to represent a NO2 concentration of 39 ppm. This is consistent with the reference spectrum concentration of 30 ppm.
An example of a transmission spectrum CO2 2500 ppm
% radiation reaching detector
Wavenumber (1/cm)
Absorbance
Sample
Reference
Wavenumber (1/cm)
H2O and CO2 FTIR Spectra
Li-Cor LI-840 CO2/H2O Gas Analyzer
Fuel-based Emission Factors (g pollutant/kg fuel)
)(2_
_
_
_
_
_
2
2
2
COc
HCc
HC
COc
COc
COCO
COc
Pc
fuelp
CMFCMFCMF
CMFEF
ρρ
ρρρρ
++=
y = 0.0049x + 0.7483
R2 = 0.9559
0
2
4
6
8
10
12
14
16
0 500 1000 1500 2000 2500 3000
CO+CO2 (ppm)
NO (ppm)
Particle measurement
Dustrak: optical measurement intensity of light scattered from aerosols, aerosol concentration < 2.5 m, or 10 m
ELPI
Electrical Low Pressure Impactor
measure of the number concentration of the particles and their aerodynamic size between 7 nm and 10 m.
GRIMM aerosol spectrometer measures light intensity scattered from the aerosol, the size of the particles, number concentration of the aerosol.
Photoacoustic Instrument
measures the magnitude of the shock wave when a laser beam heats up a light absorbing particle, correlated with aerosol black carbon mass
Filter: Gravimetric & Chemical analysis
Table 1. In-Plume Sampling Test Matrix in Camp Pendleton, CA from Nov 14 to 16, 2005.
Generator Test date Generator ModelHours used Engine year
Engine Model
Rated power (KW)
1 11/14/05Fremont MEP803A 2618 1999 ONAN CORP 10
2 11/14/05 Libby MEP803A 3103 1995 ONAN CORP 10
3 11/14/05 Libby MEP803A 2154 1994 ONAN CORP 10
4a 11/15/05 Libby MEP805A 1943 1995John Deer 4039TF002 30
5 11/15/05 Libby MEP805A 3374 1995John Deer 4039TF002 30
6 11/15/05 Libby MEP805A 1641 1995John Deer 4039TF003 30
7 11/15/05MCIIOFNW8
MEP805B 636 2002John Deer 4045TF151 30
8 11/15/05MCIIOFNW8
MEP805B 85 2002John Deer 4045TF151 30
9 11/15/05MCIIOFNW8
MEP806B 1017 2002John Deer 6068TF151 60
10 11/15/05MCIIOFNW8
MEP806B 1084 2001John Deer 6068TF151 60
11 11/15/05 Libby MEP806A 947 1995John Deer
1876F 60
12 11/15/05MCIIOFNW8
MEP806B 366 2001John Deer 6068TF151 60
13 11/16/05 Libby MEP007B 1874 n/a n/a 100
14b 11/16/05MCIIOFNW8
MEP805B 29 2002John Deer 4045TF151 30
a. Unit tested five distinct loads only
b. Unit tested cold start only.
• Time series of background corrected CO2, CO, Ethylene, and NO from Camp Pendleton 2005/11/15.
0
1000
2000
3000
4000
5000
6000
8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00
0
10
20
30
40
50
60
8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00
0
0.5
1
1.5
2
2.5
8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00
-5
0
5
10
15
20
25
30
35
40
45
50
55
8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00
Results 1): Gaseous Emission Factors
• EFs of CO, Ethylene, and NO2 all decrease with
increasing engine load• cold start emissions are higher than the hot
stabilized, except NO
0
10
20
30
40
50
60
70
80
90
10 25 50 75 100 Cold Start (0%load)
Pollutant EF (g/kg fuel)
10 kW30 kW60 kW100 kW
0
2
4
6
8
10
12
14
16
10 25 50 75 100 Cold Start (0%load)
Pollutant EF (g/kg fuel)
10 kW30 kW60 kW100 kW
0
5
10
15
20
25
10 25 50 75 100 Cold Start (0%load)
Pollutant EF (g/kg fuel)
10 kW30 kW60 kW100 kW
CO
Ethylene
NO
Continued: Gaseous Emission factors
-2
0
2
4
6
8
10
12
14
16
18
10 25 50 75 100 Cold Start (0%load)
Pollutant EF (g/kg fuel)
10 kW30 kW60 kW100 kW
-10
0
10
20
30
40
50
60
70
10 25 50 75 100 Cold Start (0%load)
Pollutant EF (g/kg fuel)
10 kW30 kW60 kW100 kW
-0.05
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
10 25 50 75 100 Cold Start (0%load)
Pollutant EF (g/kg fuel)
10 kW30 kW60 kW100 kW
NO2
Propane
+Hexane
NH3
• HC EFs generally small (< 20 g/kg fuel) and increase moderately with engine load, NH3 below detection limits.
Particle measurement Instrument Intercomparison: DustTrak PM2.5 and PM10
• the engine exhaust is composed of small particles less than 2.5 m and well-mixed
PM10 = 1.08 PM 2.5 + 7.3
R2 = 0.994
0
2000
4000
6000
8000
10000
12000
0 2000 4000 6000 8000 10000
DustTrak PM 10 (ug/m3)
DustTrak PM
2.5
(ug/m
3)
DustTrak vs GRIMM
Grimm = 0.65 DT - 143
R2 = 0.94
0
1000
2000
3000
4000
5000
6000
7000
0 1000 2000 3000 4000 5000 6000 7000
DustTrak PM 2.5 (g/m3 )
Grimm PM
2.5
(/g m
3)
Mass of particles measured by GRIMM less sensitive to changes in the size distribution, the Grimm
calculates PM2.5 mass based on an integrated measure of the particle size distribution.
DustTrak vs Photoacoustic
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 2000 4000 6000 8000 10000 12000
DustTrak PM 2.5 (g/m3 )
(Photo Acoustic BC
/g m
3)
. The relative fraction of black carbon to total aerosol mass can change as a function of engine, operating load, and air fuel mixture, weak correlation is expected.
ELPI0.263 (5 stages) vs DustTrak PM2.5
ELPI PM 0.263 = 1.36 DT PM 2.5
R2 = 0.739
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
0 2000 4000 6000 8000 10000 12000
DustTrak PM 2.5 (g/m3 )
ELPI PM
0.263
(/g m
3)
DustTrak laser light wavelength of 780 nm, less sensitive to particles < 300 nm. These two measuring independent portions of particle size distribution
Moderate correlation indicates larger particles (300 nm to 1000 nm) measured by the DustTrak are generally coincident with the smaller nano particles measured by the ELPI.
. Composite size distribution of engine exhaust PM measured by ELPI and GRIMM
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
0.01 0.1 1 10
Dp (m)
/ (dM d log D
p) (/g m
3)
ELPIGRIMM
size distributions overlap indicating that both measurements are physically consistent
ELPI is known to have a large bias for particles greater than 500 nm when sampling high
concentration (>1 mg/m3). For PM EF calculation, ELPI PM less than 0.263 is added to DustTrak PM2.5 mass
Time series of real time PM instrument measurements from Camp Pendleton Generator
0
5000
10000
15000
20000
25000
30000
8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00
20051115 Time
Concentration (
/g m
3 )
DT PM2.5Grimm PM>0.3 um
EC by PAELPI PM 0.263
Match test: concentration peaks shows well synchronized,
No need to subtract background since source is 2 orders higher.
PM fuel based emission factors for 10 kW, 30 kW generators
0
5
10
15
20
25
30
10 25 50 75 100 ColdStart (0%
load)
PM EF (g/kg fuel)
10 kW - FZ30644
10 kW - RZCO2061
10 kW - RZCO2845
PM EF
Load (%)
Engine Rating (kW)Serial No
0
5
10
15
20
25
30
10 25 50 75 100 ColdStart (0%
load)
PM Emission Factor (g/kg fuel)
30 kW - HX32455
30 kW - HX33185
30 kW - HX33189
30 kW - RZH00999
30 kW - RZH01023
30 kW - RZH01043
PM EF
Load (%)
Engine Rating (kW)
Serial NoEFs for the 10 kW generators were highest at the 100% load.
0
5
10
15
20
25
30
10 25 50 75 100 ColdStart (0%
load)
PM Emission Factor (g/kg fuel)
60 kW - HX62178
60 kW - HX62182
60 kW - HX62471
60 kW - RZJ02059
PM EF
Load (%)
Engine Rating (kW)Serial No
100 kW - RZ02630
0
5
10
15
20
25
30
10 25 50 75 100 ColdStart (0%
load)
PM Emission Factor (g/kg fuel)
100 kW - RZ02630
PM EF
Load (%)
Engine Rating (kW)Serial No
PM fuel based emission factors for 60 kW, 100 kW generators
All but the 100 kW generator showed an increase in PM EF as load increased to 75%
100 kW unit had the highest emissions and showed a steady decrease in EF as increased load
Average PM EFs based on generator rated load.
0
5
10
15
20
25
30
10 25 50 75 100 ColdStart (0%
load)
PM EF (g/kg fuel)
10 kW
30 kW
60 kW
100 kW
PM EF
Load (%)
Engine Rating (kW)
No substantial increases in emissions were seen for the cold start tests.
Average black carbon EFs based on generator rated load
0
0.2
0.4
0.6
0.8
1
1.2
1.4
10 25 50 75 100 ColdStart (0%
load)
PM EF (g/kg fuel)
10 kW
30 kW
60 kW
100 kW
Black Carbon EF
Load (%)
Engine Rating (kW)
BC EF Patterns are consistent with the total PM EFs. BC emissions were highest for the 10 kW generators operating at 100% load. The 100 kW generator had constant BC emissions for 10%-75% loads, but
increased by a factor of 3 at the 100% load.
350KW Generator-MEL (CAT 3406C, 2000) 100KW Generator-IPETS (LIBBY MEP007B, year unknown) AP 42
Load 10% 25% 50% 75% 100% Overall 10% 25% 50% 75% 100% Overall
EF CO 6.53 4.74 8.00 9.59 7.24 7.24 46.65 23.80 12.74 8.11 6.88 18.00 18.34
EF NO 24.58 31.77 37.58 36.37 30.84 33.90 8.05 12.92 15.49 11.44 12.07 12.79
85.11EF NO2 2.02 1.30 1.47 1.00 1.53 1.36 5.93 4.09 1.42 -0.46 0.16 2.14
EF HC 2.23 1.19 0.63 0.50 0.66 0.93 12.64 -0.25 5.19 30.47 21.70 11.45 6.76
EF Comparison with CE-CERT MEL generator test (1)
% Load 10 25 50 75 100 Overall 10 25 50 75 100 Overall AP 42THC 33.10 11.74 5.24 3.16 2.08 9.30 5.61 6.80 2.54 12.80 14.54 7.29 6.76CO 35.76 12.78 4.56 2.44 6.28 9.70 32.05 22.84 15.29 10.42 9.04 17.70 18.34
NOx 49.67 32.47 34.59 43.53 54.64 38.70 33.67 28.35 25.81 19.37 16.85 25.30 85.11PM 1.99 1.58 0.99 0.99 1.76 1.31 1.72 2.17 6.48 7.84 4.77 4.96 5.98
THC 30.93 15.62 6.59 4.06 1.90 10.87 12.64 -0.25 5.19 30.47 21.70 11.45CO 32.29 14.31 3.52 5.01 26.42 11.15 46.65 23.80 12.74 8.11 6.88 18.00
NOx 53.74 48.77 47.87 67.74 79.48 55.27 13.99 17.00 16.90 10.98 12.23 14.93PM 2.98 2.30 0.81 0.63 1.49 1.47 26.60 25.13 20.48 9.36 4.94 18.93
THC 26.19 9.26 5.01 3.52 3.03 7.93CO 30.48 8.58 4.15 3.75 5.96 8.10
NOx 151.28 88.51 77.22 73.61 74.06 86.95PM 3.93 1.54 0.81 0.72 0.81 1.32
MEL 125KW John Deer 6076, 1991
IPETS 60KW Average (1995,2001,2001,2002)MEL 60KW John Deer, 2001
MEL 100KW Cummins 6BT, 1990 IPETS 100KW (LIBBY MEP007B, year unknown)
EF Comparison with CE-CERT MEL generator test (2)
PM emission factors for 13 tested generators
02468
101214161820
1999 Fremont MEP803A1995 Libby MEP803A1994 LIBBY MEP803A1995 LIBBY MEP805A1995 LIBBYMEP805A1995 LIBBY MEP805A
2002 MCIIOFNW8 MEP805B2002 MCIIOFNW8 MEP805B2002 MCIIOFNW8 MEP806B2001 MCIIOFNW8 MEP806B
1995 LIBBYMEP806A
2001 MCIIOFNW8 MEP806Bunknown year LIBBY MEP007B
PM EF (g/kg fuel)
05
101520
2530
3540
1999 Fremont MEP803A1995 Libby MEP803A1994 LIBBY MEP803A1995 LIBBY MEP805A1995 LIBBYMEP805A1995 LIBBY MEP805A
2002 MCIIOFNW8 MEP805B2002 MCIIOFNW8 MEP805B2002 MCIIOFNW8 MEP806B2001 MCIIOFNW8 MEP806B
1995 LIBBYMEP806A
2001 MCIIOFNW8 MEP806Bunknown year LIBBY MEP007B
NOx EF (g/kg fuel)
NOx emission factors for 13 tested generators
Conclusions
• Gaseous EFs show a strong consistency across engine types. • EFs of CO, Ethylene, and NO2 all decrease with increasing
engine load, cold start emissions of these species higher than the hot stabilized.
• Emissions of NO increase only slightly (<50%) over the operating modes from 10% to 100%. The cold start NO EFs are lower than hot stabilized EFs.
• HC EFs generally small and increase moderately with engine load. Ammonia emissions are low detection limits
• Fleet average of CO EF is 5% lower than AP 42, NOx EF is 74% lower than AP 42 estimates.
Conclusions (2)
• Fleet average PM EF was 4.498 g/kg fuel, 25% less than the AP 42 estimates
• With exception of the 100 kW generator, all engines showed an increase in PM EF as load increased to 75%. The 100 kW unit had the highest PM emissions and showed a steady decrease in EF as load increased. No substantial increases in PM emissions for the cold start tests.
• compared with MEL of CE-CERT for similar engine sizes, while gaseous EF is comparable, the PM EF has a 3 times difference might due to different measurement methodologies.
Acknowledgement
• Hampden Kuhns, Nicholas Nussbaum, Oliver Chang, David Sodeman, Sebastian Uppupalli, Hans Mussmuller, John Watson
• Strategic Environmental Research and Development Program project funding
Q & A ?