Gaseous and Particulate
Emissions from Diesel
Generators
Dongzi Zhu
Desert 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 < 1mm, toxic air pollutants
NOx,
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)
Population density and diesel BUGs location in L.A. region
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/mile2
0–2000
2000–6000
6000–10000
> 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
Fourier Transform Infra-Red spectrometer
Source
Detector
radiation
•



•
•

Beer-Lambert law: exponential attenuation
I1/I0 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
a is absorption coefficient
C is concentration
L is the distance that the radiation travel through
the sample i
I1=I0 exp(-al)
Ai  a i Ci l
Transmission spectrum and absorbance spectrum
Absorbance
% radiation reaching detector
Sample
Reference
Wavenumber (1/cm)
An example of a transmission spectrum CO2 2500 ppm
Wavenumber (1/cm)
The (sample) region to represent a NO2 concentration of
39 ppm. This is consistent with the reference spectrum
concentration of 30 ppm.
H2O and CO2 FTIR Spectra
Li-Cor LI-840 CO2/H2O Gas Analyzer
Fuel-based Emission Factors (g pollutant/kg fuel)
16
y = 0.0049x + 0.7483
R2 = 0.9559
14
NO (ppm)
12
10
8
6
4
2
0
0
500
1000
1500
2000
2500
3000
CO+CO2 (ppm)
c _ P
 c _ CO
EFp  CMFfuel
 c _ CO
 c _ HC
CMFCO  (CMFCO
 CMFHC
)
 c _ CO
 c _ CO 2
2
2
2
Particle measurement
Photoacoustic Instrument
ELPI
Dustrak:
Electrical Low Pressure Impactor
optical measurement intensity of light scattered from
aerosols, aerosol concentration < 2.5 mm, or 10 mm
measure of the number concentration
of the particles and their aerodynamic
size between 7 nm and 10 mm.
measures the magnitude of the shock wave
when a laser beam heats up a light
absorbing particle, correlated with aerosol
black carbon mass
GRIMM aerosol spectrometer
measures light intensity scattered from the aerosol,
the size of the particles, number concentration of the aerosol.
Filter: Gravimetric & Chemical analysis
Table 1. In-Plume Sampling Test Matrix in Camp Pendleton, CA from Nov 14 to 16, 2005.
Engine year
Engine
Model
Rated
power
(KW)
Generator
Test date
Generator Model
Hours
used
1
11/14/05
Fremont
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
1995
John Deer
4039TF002
30
5
11/15/05
Libby MEP805A
3374
1995
John Deer
4039TF002
30
6
11/15/05
Libby MEP805A
1641
1995
John Deer
4039TF003
30
7
11/15/05
MCIIOFNW8
MEP805B
636
2002
John Deer
4045TF151
30
8
11/15/05
MCIIOFNW8
MEP805B
85
2002
John Deer
4045TF151
30
9
11/15/05
MCIIOFNW8
MEP806B
1017
2002
John Deer
6068TF151
60
10
11/15/05
MCIIOFNW8
MEP806B
1084
2001
John Deer
6068TF151
60
11
11/15/05
Libby MEP806A
947
1995
John Deer
1876F
60
12
11/15/05
MCIIOFNW8
MEP806B
366
2001
John Deer
6068TF151
60
13
11/16/05
Libby MEP007B
1874
n/a
n/a
100
14b
11/16/05
MCIIOFNW8
MEP805B
29
2002
John 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.
6000
5000
CO2 (ppm)
4000
3000
2000
1000
60 0
8:00
9:00
10:00
11:00
12:00
12:00
13:00
14:00
15:00
16:00
50
CO (ppm)
40
30
20
10
0
8:00
2.5
9:00
10:00
11:00
13:00
14:00
15:00
16:00
9:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
9:00
10:00
11:00
12:00
13:00
14:00
15:00
16:00
Ethylene (ppm)
2
1.5
1
0.5
0
8:00
55
50
45
40
35
NO (ppm)
•
30
25
20
15
10
5
0
-5
8:00
Results 1): Gaseous Emission Factors
90
80
CO
Pollutant EF (g/kg fuel)
70
60
10 kW
30 kW
60 kW
100 kW
50
40
30
20
10
0
10
25
50
75
100
16
Cold Start (0%
load)
Ethylene
Pollutant EF (g/kg fuel)
14
12
10
10 kW
30 kW
60 kW
100 kW
8
6
4
2
0
10
25
50
75
100
Cold Start (0%
load)
25
•
EFs of CO, Ethylene, and NO2 all decrease with
increasing engine load
cold start emissions are higher than the hot
stabilized, except NO
20
NO
Pollutant EF (g/kg fuel)
•
15
10 kW
30 kW
60 kW
100 kW
10
5
0
10
25
50
75
100
Cold Start (0%
load)
Continued: Gaseous Emission factors
18
16
12
10
10 kW
30 kW
60 kW
100 kW
8
6
4
2
0
-2
10
25
50
75
100
70
Cold Start (0%
load)
60
Propane
+Hexane
Pollutant EF (g/kg fuel)
50
40
10 kW
30 kW
60 kW
100 kW
30
20
10
0
-10
10
25
50
75
100
Cold Start (0%
load)
0.03
0.02
• HC EFs generally small (< 20 g/kg fuel)
and increase moderately with engine load,
NH3 below detection limits.
NH3
Pollutant EF (g/kg fuel)
NO2
Pollutant EF (g/kg fuel)
14
0.01
0
10 kW
30 kW
60 kW
100 k
-0.01
-0.02
-0.03
-0.04
-0.05
10
25
50
75
100
Cold Start (0%
load)
Particle measurement Instrument Intercomparison:
DustTrak PM2.5 and PM10
12000
PM10 = 1.08 PM2.5 + 7.3
R2 = 0.994
3
DustTrak PM2.5 (ug/m )
10000
8000
6000
4000
2000
0
0
2000
4000
6000
8000
10000
DustTrak PM10 (ug/m3)
• the engine exhaust is composed of small particles less than
2.5 mm and well-mixed
DustTrak vs GRIMM
7000
Grimm = 0.65 DT - 143
R2 = 0.94
3
Grimm PM2.5 (mg/m )
6000
5000
4000
3000
2000
1000
0
0
1000
2000
3000
4000
5000
6000
7000
DustTrak PM2.5 (mg/m3)
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
2000
1600
3
Photo Acoustic BC (mg/m )
1800
1400
1200
1000
800
600
400
200
0
0
2000
4000
6000
8000
10000
12000
DustTrak PM2.5 (mg/m3)
.
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
20000
18000
3
ELPI PM0.263 (mg/m )
16000
ELPI PM0.263 = 1.36 DT PM2.5
14000
R2 = 0.739
12000
10000
8000
6000
4000
2000
0
0
2000
4000
6000
8000
10000
12000
DustTrak PM2.5 (mg/m3)
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
5000
4500
ELPI
GRIMM
3
dM/d log(Dp) (mg/m )
4000
3500
3000
2500
2000
1500
1000
500
0
0.01
0.1
1
10
Dp (mm)
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
30000
DT PM2.5
Grimm PM>0.3 um
EC by PA
ELPI PM 0.263
3
Concentration (mg/m )
25000
20000
15000
10000
5000
0
8:00
9:00
10:00
11:00
12:00
13:00
20051115 Time
14:00
15:00
16:00
Match test: concentration peaks shows well synchronized,
No need to subtract background since source is 2 orders higher.
30
PM fuel based emission factors for 10 kW, 30 kW generators
PM EF
PM EF (g/kg fuel)
25
20
Engine Rating (kW)
Serial No
10 kW - FZ30644
10 kW - RZCO2061
10 kW - RZCO2845
15
10
5
0
10
25
50
75
100
Cold
Start (0%
load)
30
PM EF
EFs for the 10 kW generators were
highest at the 100% load.
PM Emission Factor (g/kg fuel)
Load (%)
25
Engine Rating (kW)
Serial No
30 kW - HX32455
30 kW - HX33185
30 kW - HX33189
30 kW - RZH00999
30 kW - RZH01023
30 kW - RZH01043
20
15
10
5
0
10
25
50
75
Load (%)
100
Cold
Start (0%
load)
PM fuel based emission factors for 60 kW, 100 kW generators
PM EF
25
Engine Rating (kW)
Serial No
60 kW - HX62178
60 kW - HX62182
60 kW - HX62471
60 kW - RZJ02059
20
15
10
All but the 100 kW generator showed an
increase in PM EF as load increased to 75%
5
0
100 kW - RZ02630
10
25
50
75
Load (%)
100
Cold
Start (0%
load)
30
PM Emission Factor (g/kg fuel)
PM Emission Factor (g/kg fuel)
30
PM EF
25
20
Engine Rating (kW)
Serial No
100 kW - RZ02630
15
10
5
0
10
100 kW unit had the highest emissions and showed
a steady decrease in EF as increased load
25
50
75
Load (%)
100
Cold
Start (0%
load)
Average PM EFs based on generator rated load.
30
PM EF
PM EF (g/kg fuel)
25
20
Engine Rating (kW)
10 kW
30 kW
60 kW
100 kW
15
10
5
0
10
25
50
75
100
Cold
Start (0%
load)
Load (%)
No substantial increases in emissions were seen for the cold start tests.
Average black carbon EFs based on generator rated load
1.4
Black Carbon EF
PM EF (g/kg fuel)
1.2
1
Engine Rating (kW)
10 kW
30 kW
60 kW
100 kW
0.8
0.6
0.4
0.2
0
10
25
50
75
100
Cold
Start (0%
load)
Load (%)
.
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
.
EF Comparison with CE-CERT MEL generator test (1)
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
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
EF 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
85.11
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
18.34
EF Comparison with CE-CERT MEL generator test (2)
% Load
THC
CO
NOx
PM
THC
CO
NOx
PM
THC
CO
NOx
PM
MEL 60KW John Deer, 2001
IPETS 60KW Average (1995,2001,2001,2002)
10
25
50
75
100 Overall 10
25
50
75
100
Overall
33.10 11.74
5.24
3.16 2.08
9.30
5.61
6.80
2.54
12.80
14.54
7.29
35.76 12.78
4.56
2.44 6.28
9.70 32.05 22.84 15.29 10.42
9.04
17.70
49.67 32.47 34.59 43.53 54.64 38.70 33.67 28.35 25.81 19.37
16.85
25.30
1.99
1.58
0.99
0.99 1.76
1.31
1.72
2.17
6.48
7.84
4.77
4.96
MEL 100KW Cummins 6BT, 1990
IPETS 100KW (LIBBY MEP007B, year unknown)
30.93 15.62
6.59
4.06 1.90 10.87 12.64 -0.25
5.19
30.47
21.70
11.45
32.29 14.31
3.52
5.01 26.42 11.15 46.65 23.80 12.74
8.11
6.88
18.00
53.74 48.77 47.87 67.74 79.48 55.27 13.99 17.00 16.90 10.98
12.23
14.93
2.98
2.30
0.81
0.63 1.49
1.47 26.60 25.13 20.48
9.36
4.94
18.93
MEL 125KW John Deer 6076, 1991
26.19 9.26
5.01
3.52 3.03
7.93
30.48 8.58
4.15
3.75 5.96
8.10
151.28 88.51 77.22 73.61 74.06 86.95
3.93
1.54
0.81
0.72 0.81
1.32
AP 42
6.76
18.34
85.11
5.98
Fr
19
em
95 ont
19 Lib ME
94 by P8
0
19 LIB ME 3A
95 BY P8
L
M 0
19 IBB E 3A
95
Y P80
20 19 LIB ME 3A
02 95 BY P8
0
20 MC LIB ME 5A
02 IIO BY P8
0
20 MC FNW ME 5A
P8
02 IIO
8
0
20 MC FNW ME 5A
01 IIO
8 P80
M FN M
EP 5B
C
W
IIO
80
8
F
M
20 19 NW E 5B
P
0
9
un 1 M 5 L 8 M 806
kn
I
B
E
C
ow IIO BBY P8
FN M 06
n
B
ye
E
ar W8 P8
LI
M 0
BB EP 6A
Y
8
M 06
EP B
00
7B
9
19
9
PM EF (g/kg fuel)
PM emission factors for 13 tested generators
20
18
16
14
12
10
8
6
4
2
0
Fr
e
19 mo
95 nt
19 Lib ME
94 by P8
0
19 LIB ME 3A
95 BY P8
LI
M 03
19 BB EP A
95
Y
80
M
L
20 19
IB
EP 3A
02 95 B Y
80
L
M
M
5
20
C IBB EP A
0 2 IIO
Y
8
FN M 05
M
20
A
E
C
02 IIO W8 P8
0
F
20 MC NW ME 5A
P8
0 1 IIO
8
M FN ME 05B
C
IIO W8 P8
0
F
20 19 NW ME 5B
P
0
9
un 1 M 5 L 8 M 806
kn
B
I
E
C
ow IIO BBY P8
FN M 06
n
B
ye
E
ar W8 P8
M 0
LI
BB EP 6A
8
Y
M 06
EP B
00
7B
19
99
NOx EF (g/kg fuel)
NOx emission factors for 13 tested generators
40
35
30
25
20
15
10
5
0
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?