United States
                   Environmental Protection
                   Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
                   Research and Development
EPA/600/S7-86/001 Apr. 1986
SERA         Project  Summary
                  Environmental Assessment  of
                  NOx Control  on a
                  Compression-Ignition,  Large-
                  Bore,  Reciprocating
                  Internal-Combustion  Engine
                  C. Castaldini
                    The report gives emission  results
                   from field testing of the exhaust gas
                   from  a large-bore,  compression-
                   ignition reciprocating engine burning
                   diesel fuel. An objective of the tests was
                   to evaluate the operating efficiency of
                   the  engine  with  combustion
                   modification NOx  control  to  reduce
                   emissions to below the proposed NOx
                   new source performance  standard
                   (NSPS) of 600 ppm at 15 percent 02
                   dry-  Engine NOx  emissions  were
                   reduced 31 percent (from 825 to 571
                   ppm) at 15 percent O2 with 3.5° of fuel
                   injection timing retard. This reduction
                   was accompanied by a 1 percent loss in
                   engine efficiency.  CO emissions
                   decreased slightly (from 119 to 90
                   ppm). Total unburned hydrocarbons
                   remained  relatively  unchanged (25
                   ppm), as did particulate emissions (35
                   ng/J) and total organic emissions (55
                   ng/J). Volatile organics (boiling point <
                   about 100° C) accounted for the largest
                   fraction  of  the  total   organic.
                   Naphthalene, fIuoroanthene,
                   phenanthrene/anthracene, and pyrene
                   were the only organic priority pollutants
                   detected in both tests at levels below 70
                   micrograms/dscm.
                    This Project Summary was developed
                   by EPA's Air and Energy Engineering
                   Research  Laboratory, Research
                   Triangle Park,  NC, to announce key
                   findings of the research project that is
                   fully documented in two separate
                   volumes of the same title (see Project
                   Report ordering information at back).
Introduction
  This report describes emission results
obtained from field testing of the exhaust
gas from  a  large-bore,  dual-fuel,
compression-ignition,  reciprocating
internal-combustion (1C) engine burning
distillate oil (diesel fuel). Objectives of the
tests were to measure exhaust  gas
emissions and to evaluate the operating
efficiency of the engine under baseline or
normal operating conditions and with
combustion modification NOx control to
reduce emissions to below the proposed
NOx New Source Performance Standard
(NSPS) of  600 ppm at  15 percent 02.
Emission  measurements included
continuous  monitoring of exhaust gas
emissions; source assessment sampling
system (SASS) sampling of the exhaust
gas with subsequent laboratory analysis
of samples to give total exhaust gas
organics in two  boiling point ranges,
compound  category information within
these ranges, specific quantitation of the
semivolatile organic priority pollutants,
and exhaust gas  concentrations of 73
trace elements; Method 5 sampling for
particulate; Method 8 sampling for S02
and S03; and grab sampling of fuel and
engine  lubricating oil  for inorganic
composition determinations.
  Engine NOx emissions were  reduced
31 percent (from 825 to 571 ppm) at 15
percent 02  with the  control approach
tested (3.5° of fuel injection timing
retard). This reduction was accompanied
by a 1 percent loss in engine efficiency
(from 36.3 to 35.3 percent). CO emissions

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decreased slightly (from 119 to 90 ppm) at
15 percent 02 under controlled operation.
Total  unburned hydrocarbon emissions
remained relatively unchanged (at about
25 ppm, as propane) at 15 percent O2, as
did  particulate  emissions at about  35
ng/J  heat input. Total organic emissions
also remained relatively unchanged at
about 55 ng/J. Volatile organics (boiling
point  less than about 100°C) accounted
for  the  largest fraction  of the  total
organic.
  Of the 58 semivolatile organic priority
pollutants analyzed, only naphthalene,
fluoroanthene, phenanthrene/anthra-
cene, and pyrene were detected  in the
uncontrolled engine exhaust at levels of 7
to 70 jug/dscm. Levels of these  in the
controlled engine exhaust were lower,
being less than  1 to 50 //g/dscm.

Summary and Conclusions
Test Engine
  The test engine was a turbocharged
1,565   kW   (2,100-Bhp),   two-stroke,
opposed-piston, compression-ignition
Model 38TDD8-1/8  engine manufactur-
ed  by  the   Fairbanks Morse Engine
Division of Colt Industries.  Figure 1, a
schematic of the engine,  shows the
turboblower  arrangement  of  the inlet
combustion air  and  the opposed-piston
design. The combustion air is drawn into
the turbocharger where it is compressed
and discharged  through an air cooler to
the positive-displacement lobe-type
blower. The blower,  driven by the upper
engine  crankshaft,  discharges the  air
directly  to the cylinders through the
engine  intake  manifold.  The  air/fuel
mixture is compressed between the two
pistons  which  work  vertically toward
each other in each  cylinder. The  upper
and  lower   pistons  drive separate
crankshafts interconnected by a vertical
drive. Hot exhaust gas leading from the
lower cylinder ports  drives the turbine of
the turbocharger  assembly. The fuel is
ignited by the heat of compression.

Engine Operation  and
Test Arrangements
  The test program called for the analysis
of  exhaust gas  samples collected  (1)
during   uncontrolled  or  baseline
operation, and  (2)  with fuel  injection
retard to lower NOxemissionsto or below
the  level of the proposed NSPS. Table 1
summarizes  the engine specifications,
operating parameters,  and atmospheric
conditions during both  tests.
  For the baseline  test, fuel  injection
timing was set at  the normal setting for
this engine, 16° before minimum volume
(RMV).  Combustion  modification NOx
control  consisted of  retarding  the fuel
injection timing from 16 to 10.5° BMV.
The effect of 5.5° retard on the operation
of the engine was a loss in efficiency of
about 1.0 percent. This efficiency loss is
clearly identifiable by the increase in fuel
flow required to maintain rated  power
output, the air flow was also increased
during the low-NOx tests as indicated by
the  increase  in  blower  discharge
pressure.  However,  the  fuel/air ratio
during the low-NOx test decreased about
8 percent from the baseline level. Blower
discharge  and  engine  exhaust  gas
temperatures remained nearly  constant
while there was a small reduction in
temperature at the turbine outlet of the
turbocharger.

Emission Measurements  and
Results
  The sampling and analysis procedures
used in this test program conformed to a
modified EPA level 1 protocol. Except for
continuous monitoring to exhaust gas
                             emissions,  all  exhaust  gases  were
                             measured at the exit of the engine muffler
                             into  the  uninsulated  exhaust  stack.
                             Emission measurements included:

                               •  Continuous monitoring for NOx,NO,
                                  CO, CO2, 02, and TUHC
                               •  Source  Assessment   Sampling
                                  System (SASS) for trace elements
                                  and organic emissions
                               •  EPA  Method  5  for  solid  and
                                  condensible  particulate  mass
                                  emissions
                               •  EPA Method 8 for S02 and  SO3
                                  emissions
                               •  Grab sample for onsite analysis of
                                  C,  to   C6  hydrocarbons by  gas
                                  chromatography (GC)
                               •  Bosch  smoke spot

                             In  addition, samples  of  the engine
                             lubricating oil and the diesel fuel oil were
                             collected for analysis.
                              The analysis protocol included:
                                •  Analyzing  the  fuel/lube oil, and
                                  SASS train samples for 73 trace
                                  elements using spark source mass
                                  spectrometry (SSMS), supplement-
                                                                Blower
                                                                (second stage
                                                                in series)
              Upper
            Crankshaft
   Compressor
   (first stage)
Figure 1.
            Exhaust
            Outlet
Schematic of turboblower arrangement (courtesy of Fairbanks Morse Division of
Colt Industries).

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      ed  by  atomic  absorption
      spectrometry (AAS)
   • Analyzing SASS train samples for
      total organic content in two boiling
      point ranges:  100to 300°Cbytotal
      chromatographable organics (TCO)
      analysis and >300°C by gravimetry
      (GRAV)
   • Analyzing the SASS train samples
      for 58 semivolatile organic species
      including many POM compounds
   • Performing  infrared (IR) spectro-
      metry analysis  of organic sample
      extracts
   • Performing  liquid  chromatography
      (LC) separation of selected sample
      extracts  with  subsequent  TCO,
      GRAV,  and  IR  analysis of  LC
      fractions
   • Performing  direct insertion probe
      and batch inlet low resolution mass
      spectrometry  (LRMS)  of selected
      sample extracts
  Bioassay tests were also performed on
the SASS organic sorbent module extract
to  estimate  this  sample's   potential
toxicity and mutagenicity.
  Table  2  summarizes  exhaust  gas
emissions measured in the test program.
Emissions are presented  as ng/J heat
input and as mg/dscm of exhaust.
  As noted in Table  2, NOx emissions
were reduced with fuel injection retard to
1,040 ng/J from a  baseline of 1,490
ng/J. CO emissions were also decreased
slightly.  TUHC,  paniculate,   and  total
semivolatile  organic emissions  were
relatively unchanged; nonvolatile organic
emissions   increased  with   low-NOx
operation.
  As  a  measure  of  the  potential
significance of the  emissions  levels for
further monitoring  evaluation. Table 2
also   lists  occupational  exposure
guidelines for most pollutants noted in
the  table.  The  guidelines  listed  are
generally either time-weighted-average
Threshold Limit Values (TLV) established
by  the  American  Conference  of
Governmental Industrial Hygienists, or
the   8-hr  time-weighted-averaged
exposure  limits  established   by  the
Occupational  Safety  and   Health
Administration. These are noted only to
aid    in  ranking   the  emissions   for
evaluation.  In  this respect,  pollutants
emitted  at  levels  several  orders  of
magnitude higher than their  guideline
might warrant  further consideration,
while  species  emitted  at  levels
significantly lower than their  guideline
might be considered of lesser concern.
Only  elements   emitted  at  levels
Table 1.    Compression Ignition Engine Design and Operating Parameters
Engine Design Parameters Specifications

  Model designation
  Engine configuration
  Bore/stroke, m (in.)
  Number of cylinders
  Displacement/cylinder, m3 (in.3)
  Compression ratio
  BMEP. MPa tpsia)
  kW/cylinder (Bhp/cylinder) rpm
  Injection timing
  Lubricating oil
  Lubricating oil consumption, ml/s (gph)
  Fuel oil
  Hours since last overhaul
Engine Operating Parameters

  RPM (percent rating)
  kW, (Bhp) (percent rating)
  Generator output, kWe (percent rating)
  Fuel flow, g/s(lb/hr)
  BSFC. g/kW-hr(lb/Bhp-hr)
  Fuel rate, k W, in/k Wt out (Btu/Bhp-hr)
  Injection timing
  Cylinder firing pressure, MPa (psig)
  Compressor inlet air temp., K (°F)
  Compressor outlet air temp., K (°F)
  Blower suction temp.. K (°F)
  Blower discharge temp., K (°F)
  Blower discharge pressure, kPa (psig)
  Air flow, kq/s (Ib/min)
  Fuel/air ratio
  Combined cylinder exhaust temp.,
    K(°F)
  Turbine exhaust temp., K (°F)
  Engine efficiency, percent

Average Ambient Atmospheric Condition

  Ambient temperature—dry bulb, K (°F)
  Barometric pressure, kPa (in. Hg)
  Relative humidity, percent
 38TDD8-1/8
 2-stroke, opposed-piston
 0.206/0.254 (8-1/8/10) x 2
 6
 0.017(1.037)
 11:1
 1.01 (148.5)
 261 (350) at 900 rpm
 16° before minimum volume (BMV)
 Mobil 446
 0.37 (0.35)
 No. 2
 30
                                         Baseline
                          Low-NO*
900 (100%)
1566 (2100) (100%)
1503 (9.8%)
97.7(775)
225(0.37)
2.75(7009)'
16.0° BMV
9.02-9.23(1320-1350)
305 (89)
417(292)
324 (124)
338 (149)
150 (22.0)
4.05 (535)
0.02414

757 (903)
636 (686)
36.3
304 (88)
97.3 (28.82)
37
900 (100%)
1567(2101)1100%)
1505(99.8%)
101 (798)
231 (0.38)
2.84(7218)'
10.5° BMV
8.20-8.34 (1200-1220)
291 (66)
414(286)
327(130)
340 (153)
176(25.7)
4.52 (598)
0.02223

754 (898)
625 (665)
35.3
290 (63)
98.2 (29.07)
45
'Heat input accounts for the heating value of lube oil burned by the engine.
exceeding 10 percent of their guideline
are noted in Table 2.
  Table  2   shows  that several trace
elements were emitted at levels up to
eight times  their respective guidelines.
For  comparison,   emissions  of  the
gaseous  pollutants  CO,  SO2, and SO3
were at levels ranging from 2 to 20 times
their guidelines; NOx emissions were at
levels over 300 times its guideline. These
comparisons suggest thattheNOxcontrol
achieved may be the  most  significant
change.
  Analyses  of SASS train samples for
POM and other organic compounds (the
semivolatile  organic priority  pollutants
species) were  performed.  Only
    naphthalene, fluoroanthene, phenanth-
    rene/anthracene,   and  pyrene   were
    detected in the baseline test exhaust gas
    at levels of 7 to 70 //g/dscm. Levels of
    these compounds in  the low-NOx test
    exhaust gas were lower, from less than 1
    to 50 /ug/dscm.
      SASS  train organic extract  samples
    were subjected to LC fractionation, with
    TCO, GRAV, IR, and LRMS analysis of LC
    fractions, in attempts to elucidate the
    chemical character of the exhaust gas
    organic  material.  These analyses
    suggested that  the exhaust gas organic
    for both tests  was primarily  aliphatic
    hydrocarbons  with  some  esters,
    carboxylic acids,  phenols,  mercaptans,

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Table 2.    Summary of Exhaust Gas Emissions'
         Compound
                                         Baseline Test
                               (ng/J Heat
                                 Input)
(mg/dcsm)
                                                                               Low-NOt
      (ng/J Heat
        Input)
                 (mg/dscm)
                  Occupational
                   Exposure
                   Guideline
                   (ug/dscmf
Criteria Pollutants and
Other Vapor Species
CO
TUHC(asC3H6)
S03
Solid paniculate
Condensible paniculate
Total semivolatile organics
Total nonvolatile organics
                                 1.490
                                   130
                                    45
                                    44
                                    11
                                    29. 5
                                     3.3

                                     1.1

                                     3.5
 1,940
  170
   59
   57
   14
   38.4
    4.5

    1.5

    4.6
       1.040
         98
         42
         95
          19
         36.6
           1.2

          12.2
/,230
  117
  50
  113
  23
  43.7
                     1.4

                    14.5
                                      6.0
                                    55
                                       _C

                                      5.0
                                      1.0

                                    10.0"
Trace Elements
Phosphorus, P
Copper, Cu
Iron, Fe
Silver, Ag
Potassium, K
Sodium, Na
Calcium, Ca
Aluminum, Al
Zinc, Zn
Chromium, Cr
Lead, Pb
Nickel. Ni
Selenium. Se
>0.61
0.062
0.020
0.0085
>1.1
>0.63
>0.54
0.53
0.065
0.0020
0.0007
0.012
0.020
XJ.79
0.081
0.026
0.011
>1.4
>0.82
X3.70
0.69
0.085
0.0026
0.0009
0.0/5
0.026
0.045
0.34
0.92
<0.0017
XJ.60
>0.55
—
0.0/0
0.23
0.0/0
0.0072
0.0034
0.023
0.054
0.40
/./
<0.0020
XJ.72
>0.65
—
0.0/2
0.27
0.0/2
0.00087
0.004 1
0.027
0.10
0.1 Of
1.0
0.010
2.09
2.09
2.0
2.0
1.0
O.O5O
0.050'
0.10
0.20
'Exhaust Ox and COx levels were 13.7 and 5.3 percent, respectively, for the baseline test and 14.3 and 5.0 percent, respectively, for the low-NOi test.
''Time-weighted-average TLV unless noted.
°/Vo occupational exposure guideline applicable.
"For nuisance paniculate.
'Sample lost.
18-Hr time-weight-average OSHA exposure limit.
 and  low-molecular-weight  fused-ring
 aromatics (e.g.  naphthalene  and  alkyl
 naphthalenes).
   Bioassay tests were performed on the
 organic sorbent module extract from the
 SASS trains for both tests. The health
 effects bioassay tests performed were the
 Ames mutagenicity assay, and the CHO
 cytotoxicity assay. The  results of these
 assays are summarized in Table 3. The
 results suggest that the exhaust gas
 under  both   baseline  and   low-NO x
 operation is of moderate to high toxicity
 and  moderate  mutagenicity.  This is  a
 typical bioassay response for combustion
 source SASS train XAD-2 extract.
                                         Table 3.    Bioassay Analysis Results
                                           Sample
                                         XAD-2
                                           Extract

                                         XAD-2
                                           Extract
                                                              Bioassay Analysis
    Test
CHO'
Ames
   Baseline
               H
   Low-NO *   H/M
                        M
                        M
                                         *H = High toxicity, M - Moderate toxicity.
                                         tiM = Moderate mutagenicity.
                                                                          •&U. S. GOVERNMENT PRINTING OFFICE: 1986/646-116/20797

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    C. Castaldini is with Acurex Corp., Mountain View, CA 94039.
    Robert E. Hall is the EPA Project Officer fsee below).
    The complete report consists of two volumes entitled "Environmental Assessment
      ofNOx Control on a Compression-Ignition, Large-Bore, Reciprocating, Internal-
      Combustion Engine:"
      "Volume I.  Technical Results." {Order No. PB 86-155 819/AS; Cost: $16.95,
        subject to change).
      "Volume II. Data Supplement."(Order No. PB 86-155 827/AS; Cost: $16.95.
        subject to change).
    The above reports will be available only from:
            National Technical Information Service
            5285 Port Royal Road
            Springfield, VA 22161
            Telephone: 703-487-4650
    The EPA Project Officer can be contacted at:
            Air and Energy Engineering Research Laboratory
            U.S. Environmental Protection Agency
            Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300

EPA/600/S7-86/001
             000Q329   PS
                                             60604

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