vvEPA
                                United States
                                Environmental Protection
                                Agency
                                Industrial Environmental Research
                                Laboratory
                                Cincinnati OH 45226
                                Research and Development
                                EPA-600/PS7-80-148   Sept. 1980
Project  Summary
                                Environmental  Assessment  of
                                a  Waste-to-Energy  Process,
                                Burlington  Electric's  Wood
                                and  Oil  Co-Fired  Boiler
                                Mark A. Golembiewski, K.P. Ananth, T. Sutikno and
                                Harry M. Freeman
                                 In July 1978, Midwest Research In-
                                stitute conducted a series of emission
                                tests  at  the  Burlington  Electric
                                Department's power plant  in  Bur-
                                lington, Vermont.  The study  was
                                designed  to provide multi-media
                                emission data for the purpose of iden-
                                tifying  potentially  adverse  envi-
                                ronmental impacts,  and to identify
                                pollution-control technology  needs.
                                 The No. 1 boiler at Burlington Elec-
                                tric, which was tested for this study,
                                is fueled by  a combination of wood
                                chips and No. 2 fuel oil. Approxi-
                                mately  82%  of the  heat input (9.3
                                tons/hr) was provided by the wood
                                fuel and the remaining 18% by the fuel
                                oil  (175 gal/hr). Electrical  power
                                generated from this boiler system
                                was about 8 MW. The air pollution-
                                control system consists  of  two
                                mechanical collectors in series.
                                 Four effluent streams were sampled
                                and analyzed for this assessment pro-
                                gram: bottom ash, primary collector
                                ash, secondary  collector ash,  and
                                stack  emissions. Common  to  all
                                streams were characterizations for
                                elemental  composition and poten-
                                tially hazardous compounds such as
                                polychlorinated biphenyls  and
                                polycyclic aromatic hydrocarbons. In
                                addition, the boiler exhaust gases
                                were analyzed for paniculate, NOx,
                                S02, CO, and total hydrocarbon con-
                                centrations. The Source Assessment
                                Sampling  System was also  used,
                                following  guidelines established  by
                                EPA's Level 1 environmental assess-
                                ment protocol.
                                 This publication is a summary of the
                                complete project report, which can be
                                purchased  from  the National
                                Technical Information Service.

                                Introduction
                                 Under the sponsorship of the U.S. En-
                                vironmental Protection Agency's Fuels
                                Technology  Branch  in Cincinnati,
                                Midwest  Research  Institute (MRI)  is
                                presently conducting multi-media envi-
                                ronmental assessments of various waste-
                                to-energy conversion systems. This paper
                                will discuss the results of one such effort
                                at the Burlington Electric Department's
                                power plant in Burlington, Vermont. The
                                Burlington  plant was selected for study
                                because of the renewed interest in wood
                                and wood waste as a primary boiler fuel in
                                certain regions of the country. The Bur-
                                lington plant is the only facility in the U.S.
                                presently firing oil with wood waste  to
                                generate electric power.
                                 The sampling and analysis program  at
                                Burlington was designed to provide multi-
                                media emission data for the purpose  of
                                identifying  potentially adverse environ-
                                mental impacts and assessing pollution-

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control needs. In the following sections of
this paper, we will briefly describe the test
facility,  the sampling and  analysis pro-
cedures that were used,  and the results of
the test program. An assessment of the
results  using  EPA's Source Analysis
Model (SAM-1A) is also presented.

Description  of Boiler Test
Facility
  The No. 1 Unit at the Burlington Elec-
tric plant was originally a coal-fired boiler
that was modified to fire wood chips with
supplementary oil injection. Steam pro-
duced  to  power  a  10  MW  turbine
generator is rated at 100,000 Ib/hr.
  Wood chips  are conveyed  from the
storage  bin to  four gravity-fed  chutes.
From the base of the chutes, the chips are
injected into the boiler using compressed
air. The wood chips fall onto a horizontal,
traveling grate  which  is  supplied with
underfire  air.   Because  of   the  high
moisture content of the chips, the boiler
cannot provide the  needed steam output
from wood alone; therefore, supplemen-
tary fuel oil is used. No. 2 fuel oil, along
with overfire air, is  introduced above the
grate  bed from both sides of the firebox,
thus insuring adequate steam production.
Residual ash is discharged at the end of
the grate into a hopper, from which it is
removed  pneumatically to  an  outdoor
storage silo.
  The  flue gases leaving  the  boiler  are
ducted to  an  emission control system
consisting  of  two,  high   efficiency
mechanical collectors in series. For a flue
gas flow rate of 60,000 acfm at 330° F,  the
collectors  were designed  for  an overall
pressure drop of 6.5 in. H20 and a collec-
tion efficiency of 97.75%.


Sampling and Analysis
Methodology
  The sampling and analysis test matrix
that was used is shown in Figure 1. The
input  fuels, bottom ash, primary  and
secondary collector ash, and air emissions
at collector inlet and outlet were sampled.
Three complete sets of samples from each
of these streams were taken over a two-
day period. The sampling and  analysis
procedures  used   were  either  EPA
methods or those approved by the EPA
project officer. Results of the sampling
and analysis efforts are discussed below.
Results
  Input Fuels—The wood/oil feed ratio
during the MRI tests was approximately
80% wood and 20% oil, on a heat input
basis.  The average composition of the
wood was 4.3% ash, 70% volatile matter,
and 25.7% fixed carbon (dry basis). The
average sulfur content was 0.35% and the
average heat of combustion was 5,870
Btu/lb (as received) and 9,480 Btu/lb (dry
basis). The sulfur content of the oil was
0.35%, v\/hile its heat  of  combustion
average was 19,500 Btu/lb (138,100
Btu/gal).
  Bottom Ash—Analysis  of  elemental
composition in bottom ash indicated that
most elements were more concentrated in
the bottom ash relative to the fuel inputs.
Those elements exhibiting the largest in-
creases in concentration were Ba, Zr, Sr,
and Li. No PCB materials were detected in
the bottom ash samples above the 0.05
^g/g  detection  limit. One PAH  com-
pound, phenanthrene, was identified at a
concentration of 0.89 ng/g.
  Analysis for PCB materials at 0.05 pg/g
detection limit was  negative in  the ash
samples. No PAH compounds were iden-
tified in the primary ash sample extracts.
Wood Feed
 Collector Inlet
Collector Outlet
 Samp/ing- Take Three 5-Liter Samples
           Each Day. Mix and
           Extract a 1 -Liter Composite
 Analysis: Determine H2O Content
           HHV. Proximate/Ultimate
           Elemental Analysis by
           SSMS
Oil Feed
Sampling:
Analysis.
Bottom Ash
Samp/ing:
Analysis:
Take One or Two 0.5-L/ter
Samples
HHV, Proximate/Ultimate
Elemental Analysis by
SSMS
Oil 	 *-
Wood 	 *•
Take Three 1 kg Samples
Each Day, Mix and Extract
1 kg Composite
Elemental Analysis by
SSMS
PCB/PAH
 Sampling and Analysis'
 a.   Method 5-Particu/ate -  1 Per Day
     Elemental Analysis by SSMS°
 b.   Orsat (02 & CO2)
 c.   Particle Sizing - 1 Per Day
                                        Wickes Boiler
                                        85,000 Ibs/hr
r
hr

r
                                                                        V
 Sampling and Analysis:
 a.  Method 5-Particu/ate - 1 Run Per
     Day Elemental Analysis by SSMS*
 b   Orsat (O2 & C02)
 c.  Particle Sizing -  1 Run Per Day
 d.  Opacity (Method-9) - Two 1 Hr
     Tests/Day
 e.  Continuous Analyzers (Oz, NO*,
     SOz  HC, CO)
 f.  PCB/PAH with Florist I Train -
     2 Runs
 g.  SASS - 1 Run
     Analyze Per Level 1 Requirements
                                          Primary & Secondary Collector Ash
                                                                                   Sampling.   Take a 1 kg Grab Sample
                                                                                               Each Hour - Mix & Extract
                                                                                               1 kg Composite
                                                                                    Analysis:   SSMS
                                                                                               PCB/PAH
                                        Bottom Ash
                         Primary   Secondary
                         Collector  Collector
                         Ash      Ash
                                                                           * Atomic Absorption Analysis May Be Conducted
                                                                           Based on Results of SSMS Analysis
Figure 1.     Test matrix for Burlington Electric's wood and oil-fired power plant

                                   2

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However,  several compounds were con-
firmed in the secondary ash samples, in-
cluding acenapthylene,  phenanthrene,
fluoranthene, and pyrene.  One sample
contained   10 ng/g  of  phenanthrene,
which was the highest PAH concentration
observed.
  Uncontrolled  Air  Emissions—The
average uncontrolled paniculate concen-
tration was 2.96 g/dscm (1.30 gr/dscf) as
measured  by EPA Method-5. On the basis
of heat input,   uncontrolled  paniculate
emissions   averaged  1.47  g/MJ  (3.43
lb/106  Btu). Oxygen and  carbon dioxide
contents  averaged   12.3%  and  8.2%,
respectively.  Filter   samples  from  the
Method-5  paniculate tests were analyzed
for elemental composition. The elements
emitted at concentrations greater that 10
ng/dscm were Pb,  Ba, Sr, As, Ga, Zn,
Cu, Fe, Mn, Ti, and P.
  An optical/diffusional particle counting
system was used to measure the particle
size distribution of the uncontrolled emis-
sions.  Particles  in the range of 0.005 to
0.10 urn were counted by  a diffusion bat-
tery/condensation  nuclei  counter ar-
rangement, while those in the 0.3 to 2.6
/jm  range were  counted by  an optical
counter. Because the dilution system con-
sistently became plugged with larger par-
ticles during operation, no particle counts
could be obtained in the size region above
2.6 urn. Therefore, the mean particle size
could not  be determined.  Within the size
range of particles counted (0.005 to 2.6),
the  majority of the particles appeared to
be between 0.3 to 0.5 pirn in diameter.
  Controlled Air Emissions-Using con-
tinuous gas analyzers, concentrations of
02,  NOX,  SO2,  CO,  and total  hydro-
carbons (THC)  were measured in the
stack gas. NOX, and SOz concentrations

                          P  P
and  V  were in the range  of  1  to 75
fxg/dscm. The  remaining  elements had
concentrations  which were  less than 1
ng/dscm.
  Particle size data was obtained by the
same method used at the collector inlet
(optical/diffusional particle counter). As
with the inlet measurements, data for par-
ticles > 2.6 ^m in diameter could not be
obtained.  The number of  small  particles
« 2.6 jim)  appeared to increase in the
controlled gas stream relative to the un-
controlled emissions. The reasons for this
increase are not clear.
  Plume opacity data,  obtained   using
EPA Method-9, averaged about 20% on
both test  days. Samples for analysis of
PCB and PAH materials were collected in
a special sampling train utilizing impingers
and a Florisil adsorbent trap. PCB analysis
did  not produce any responses greater
that the 1 ng/sample detection limit of the
GC/MS analytical  technique.  Similarly,
no PAH compounds were identified at
levels which permitted structural confir-
mation.
  Organic analysis of the Source Assess-
ment Sampling System   (SASS)   com-
ponents,  in accordance  with  Level  1
guidelines, revealed low levels of organic
constituents.  Characterization  of the
organic  emissions was difficult, although
they appeared to be composed mainly of
carbonyl-containing groups.
Source Assessment Model
(SAM-1A)
  The  EPA's SAM-1A methodology was
applied to the  four effluent streams as a
means  of  interpreting  the  emission
results. The SAM-1A analysis results in-
dicated that the secondary collector ash
contained  the  highest degree of hazard,
although  all three ash  streams  were
similar  in the magnitude of their hazard
values. Stack  emissions  showed  a
relatively low degree of hazard.
  The  primary collector ash stream had
the highest Toxic Unit Discharge Rate
(TUDR) which  would seem to indicate
that this effluent should receive the first
priority for control measures. However,
because of certain limitations which are
inherent in  the  SAM-1A  methodology,
this observation should not be regarded
as being definitive.

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However,  several compounds were con-
firmed in the secondary ash samples, in-
cluding acenapthylene,  phenanthrene,
fluoranthene, and  pyrene.  One  sample
contained   10 ng/g  °f  phenanthrene,
which was the highest PAH concentration
observed.
  Uncontrolled Air  Emissions—The
average uncontrolled paniculate concen-
tration was 2.96 g/dscm (1.30 gr/dscf) as
measured  by EPA Method-5. On the basis
of  heat input,   uncontrolled  paniculate
emissions   averaged  1.47  g/MJ  (3.43
lb/106 Btu). Oxygen and  carbon  dioxide
contents  averaged   12.3%  and 8.2%,
respectively.  Filter   samples  from  the
Method-5  particulate tests were analyzed
for elemental composition. The elements
emitted at concentrations greater that 10
ng/dscm were Pb,  Ba, Sr, As, Ga, Zn,
Cu, Fe, Mn, Ti, and P.
  An optical/diffusional particle counting
system was used to measure the particle
size distribution of the uncontrolled emis-
sions. Particles in the range of 0.005 to
0.10 fim were counted by a diffusion bat-
tery/condensation   nuclei  counter  ar-
rangement, while those in the 0.3 to 2.6
^m range  were  counted by an optical
counter. Because the dilution system con-
sistently became plugged with larger par-
ticles during operation, no particle counts
could be obtained in the size region above
2.6 urn. Therefore, the mean particle size
could not  be determined.  Within the size
range of particles counted (0.005 to 2.6),
the majority of the particles appeared to
be between 0.3 to 0.5 urn in diameter.
  Controlled Air Em/ss/ons-Using con-
tinuous gas analyzers, concentrations of
02,  NOx,  S02,  CO,  and total  hydro-
carbons (THC)  were measured in the
stack gas. NOX, and SOa concentrations
averaged  66 and 138 ppm, respectively.
CO readings averaged 213 ppm and
THC concentrations were only 9 ppm.
  Three Method-5 particulate runs  were
made simultaneously with the sampling
runs at the collector inlet.  The average
particulate  concentration  was  0.18
g/dscm (0.08 gr/dscf).  The  particulate
emission rate averaged 0.09  g/MJ  (0.17
lb/106 Btu), on the  basis of heat input.
The average efficiency of the two-stage
mechanical collection system,  as deter-
mined from the simultaneous inlet/outlet
tests, was 94.2% for total particulate.
  Elemental analysis of the Method-5 par-
ticulate filters indicated moderately high
elemental concentrations.  Pb, Ba, Sr, Zn,
and Ti were present at the  highest con-
centrations,  approaching  100 /jg/dscm,
while  Hg, Sb, Zr, Br, Se, As, Ga,  Cu, Ni,
and  V were in  the range of 1  to  75
ng/dscm.  The remaining  elements had
concentrations which were less  than 1
  Particle size data was obtained by the
same method  used at the collector inlet
(optical/diffusional particle counter). As
with the inlet measurements, data for par-
ticles > 2.6 fjm in diameter could not be
obtained. The number of small  particles
« 2.6 ^m) appeared to increase in the
controlled gas stream relative to the un-
controlled emissions. The reasons for this
increase are not clear.
  Plume  opacity  data,  obtained  using
EPA Method-9, averaged about  20% on
both test days. Samples for analysis of
PCB and PAH  materials were collected in
a special sampling train utilizing impingers
and a Florisil adsorbent trap. PCB analysis
did  not produce any  responses greater
that the 1 ^g/sample detection limit of the
GC/MS analytical  technique. Similarly,
no  PAH  compounds were identified at
levels which permitted  structural confir-
mation.
  Organic analysis of the Source Assess-
ment Sampling  System (SASS)  com-
ponents,  in  accordance with  Level  1
guidelines, revealed low levels of organic
constituents.   Characterization  of  the
organic emissions was difficult, although
they appeared to be composed mainly of
carbonyl-containing groups.
Source Assessment Model
(SAM-1A)
  The EPA's SAM-1A methodology was
applied to the four effluent streams as a
means  of  interpreting  the  emission
results. The SAM-1A analysis results in-
dicated that the secondary collector ash
contained  the highest degree of hazard,
although  all  three ash  streams were
similar  in the magnitude of their hazard
values.  Stack  emissions   showed  a
relatively low degree of hazard.
  The primary collector ash  stream  had
the highest Toxic  Unit Discharge  Rate
(TUDR) which would seem  to indicate
that this effluent should receive the first
priority for control measures.  However,
because of certain limitations which are
inherent in the SAM-1A methodology,
this observation should not be regarded
as being definitive.
   Mark A. Golembiewski, K. P. Ananth and T. Sutikno are with Midwest Research
     Institute, Kansas City, MO 64110.
   Harry M. Freeman is the EPA Project Officer (see below).
   The complete report, entitled "Environmental Assessment of a Waste-to-Energy
     Process,  Burlington  Electric's  Wood and Oil Co-Fired Boiler,"(Order  No.
     PB 80-220627; Cost $12.00, subject of change) will be available from:
         National Technical Information Service
         5285 Port Royal Road
         Springfield, VA 22161
         Telephone: 703-557-4650
   The EPA Project Officer can be contacted at:
         Industrial Environmental Research Laboratory
         U.S.  Environmental Protection Agency
         Cincinnati, OH 45268

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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
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