United States       Air and Energy Engineering         EPA-600/8-89-057
            Environmental Protection  Research Laboratory            August 1989
            Agency          Research Triangle Park, NC 27711

             Research and Development
vEPA      Municipal Waste
            Combustion
            Assessment:
            Combustion Control
            at New Facilities
            Prepared For
            Office of Air Quality Planning and Standards

            Prepared By
            Air and Energy Engineering Research Laboratory
            Research Triangle Park, NC 27711
                                     This document is printed on recycled paper

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                                           EPA-600/8-89-057
                                           August 1989
 MUNICIPAL WASTE COMBUSTION  ASSESSMENT:
  COMBUSTION CONTROL  AT NEW  FACILITIES
                 Prepared by
                P.J.  Schindler
 Energy and Environmental  Research  Corporation
       3622 Lyckan Parkway.  Suite  5006
               Durham, NC 27707

        Under Contract No.  68-03-3365
           Work Assignment No. 1-05
    EPA Project  Officer:  James D. Kilgroe
Air and Energy  Engineering Research Laboratory
       Research Triangle Park.  NC   27711
                 Prepared for
     U.S.  Environmental Protection Agency
      Office  of  Research and Development
            Washington.  DC   20460

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                         REVIEW  NOTICE AND DISCLAIMER

      The information in this document  has  been funded wholly by  the  United
States Environmental  Protection  Agency under Contract No. 68-03-3365 to Energy
and Environmental Research Corporation.   It has been subject  to  the Agency's
peer and administrative  review (by  both  the Office of Research and Development
and the Office  of  Air  Quality Planning  and  Standards),  and  it has  been
approved for  publication  as  an  Agency  document.   Mention of trade names or
commercial products  does  not constitute endorsement  or recommendation  of  a
commercial  product by the  Agency.

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                                   ABSTRACT

      The  EPA's  Office  of Air  Quality Planning  and Standards  (OAQPS)  is
developing emission  standards  and guidelines for new and  existing  municipal
waste combustors (MWCs) under the  authority  of Sections  lll(b)  and  lll(d)  of
the Clean Air Act (CAA).   The  EPA's  Office  of  Research and Development (ORD)
is providing  support in developing  the  technical  basis  for good combustion
practice (GCP),  which is included as  a  regulatory alternative in the standards
and guidelines.   This  report provides  the supporting  data  and  rationale used
to establish baseline emission  levels for model plants that represent portions
of the  planned  and  projected  population of MWCs.    The baseline  emissions
represent performance levels  that are expected to be achieved by new plants  in
the MWC population that incorporate  GCP.  The  baseline emissions, which were
developed using  the  data base from the  newest units in the existing population
of MWCs,  establish   performance  levels against which the effectiveness and
costs of emission  control  alternatives  can be evaluated.

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                                   FOREWORD


      Based  upon  its  analysis of  Municipal  Waste  Combustors  (MWCs),  the
Environmental Protection Agency  (EPA)  has determined that MWC  emissions  may
reasonably be anticipated to contribute to the  endangerment  of  public  health
and welfare and warrant further regulation.   As a  result.  EPA's  Office  of  Air
Quality Planning and Standards is developing emission standards  for  new MWCs
under Section lll(b) of  the  Clean Air Act (CAA) and guidelines  for  existing
MWCs under Section  lll(d) of  the CAA.


      In support of these regulatory development efforts, the Air  and  Energy

Engineering  Research Laboratory  in  EPA's  Office of Research  and Development

has  conducted an  in-depth  assessment  of combustion  control  practices  to
minimize  air emissions  from  MWCs.   The results of  this  assessment  are
documented in the  following  reports:


      Municipal  Waste Combustion  Assessment:   Combustion  Control  at New
      Facilities.  August  1989 (EPA-600/8-89-057)

      Municipal  Waste  Combustion  Assessment:   Combustion  Control  at
      Existing Facilities.  August  1989 (EPA-600/8-89-058)

      Municipal  Waste  Combustion  Assessment:   Fossil  Fuel  Co-Firing.
      July 1989  (EPA-600/8-89-059)

      Municipal  Waste Combustion Assessment:  Waste Co-Firing, July 1989
      (EPA-600/8-89-060)

      Municipal  Waste Combustion  Assessment:   Fluidized Bed  Combustion.
      July 1989  (EPA-600/8-89-061)

      Municipal  Waste Combustion Assessment:    Medical Waste  Combustion
      Practices  at  Municipal  Waste  Combustion Facilities,  July 1989 (EPA-
      600/8-89-062)

      Municipal  Waste Combustion Assessment:    Technical  Basis for Good
      Combustion  Practice. August  1989 (EPA-600/8-89-063)

      Municipal  Waste Combustion, Multi-Pollutant  Study.  Emission  Test
      Report,  Maine  Energy  Recovery  Company,   Refuse-Derived  Fuel
      Facility.  Biddeford,  Maine.  Volume I.  Summary  of  Results,  July
      1989 (EPA-600/8-89-064a)

      Municipal  Waste Combustion, Multi-Pollutant  Study.  Emission Test
      Report. Mass  Burn  Refractory  Incinerator, Montgomery County South,
      Ohio,  Volume  I.  Summary of  Results,  August 1989  (EPA-600/8-89-
      065a)
                                      iii

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      The specific  objective of this  document,  "Municipal Waste  Combustion
Assessment:   Combustion  Control  at  New  Facilities," is to present the data and
supporting rationale used to establish baseline emission  estimates  for  a set
of MWC model plants.  Each model plant represents  a  class  of  MWCs  which will
be regulated by  the Section  lll(b) New Source Performance Standards (NSPS).
The emission estimates  provide  a baseline against which  emission  reductions
and costs of control alternatives were  evaluated.
                                       IV

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                                   CONTENTS
SECTION                                                           PAGE

1.0     SUMMARY  	    1-1
2.0     BACKGROUND  	    2-1
3.0     MODEL PLANT PERFORMANCE ESTIMATES  -
        MASS  BURN COMBUSTORS  	    3-1
        3.1   CONVENTIONAL MASS BURN WATERWALL MWCs  	    3-2
             3.1.1   EMISSIONS DATA FOR EXISTING FACILITIES       3-2
                     3.1.1.1   MILLBURY. MASSACHUSETTS 	    3-7
                     3.1.1.2   PINELLAS COUNTY,  FLORIDA	    3-7
                     3.1.1.3   TULSA, OKLAHOMA 	    3-8
                     3.1.1.4   MARION COUNTY.  OREGON 	    3-9
                     3.1.1.5   ALEXANDRIA,  VIRGINIA 	    3-10
                     3.1.1.6   COMMERCE. CALIFORNIA 	    3-10
                     3.1.1.7   OLMSTEAD COUNTY.  MINNESOTA 	    3-11
             3.1.2   MODEL PLANT BASELINE  EMISSIONS 	    3-12
        3.2   SPLIT  FLOW REFRACTORY  MWCs 	   3-14
             3.2.1   EMISSIONS DATA FOR EXISTING FACILITIES ...    3-16
                     3.2.1.1   McKAY BAY. FLORIDA 	    3-16
                     3.2.1.2   NYKOPING. DENMARK 	    3-18
             3.2.2   MODEL PLANT BASELINE  EMISSIONS 	    3-18
        3.3   ROTARY WATERWALL MWCs  	   3-19
             3.3.1   EMISSIONS DATA FOR EXISTING FACILITIES  ...   3-20
             3.3.2   MODEL PLANT BASELINE  EMISSIONS  	   3-20
        3.4   MODULAR EXCESS AIR MWCs  	  3-22
             3.4.1   EXISTING FACILITIES EMISSIONS DATA   	   3-22
                     3.4.1.1   PITTSFIELD.  MASSACHUSETTS  	   3-22
                     3.4.1.2   PIGEON POINT.  DELAWARE 	   3-27
                     3.4.1.3   ALEXANDRIA.  MINNESOTA 	   3-27
             3.4.2   MODEL PLANT BASELINE  EMISSIONS  	   3-28
        3.5   MASS BURN MODULAR STARVED AIR MWCs 	    3-30
             3.5.1   EXISTING FACILITIES EMISSIONS DATA  	   3-31
                     3.5.1.1   PRINCE EDWARD ISLAND	   3-31
                     3.5.1.2   CATTARAUGUS  COUNTY.  NEW YORK 	   3-36
                     3.5.1.3   ONEIDA COUNTY.  NEW YORK 	   3-36
                     3.5.1.4   ADDITIONAL DATA 	   3-36
             3.5.2   MODEL PLANT BASELINE  EMISSIONS 	   3-37

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                             CONTENTS (continued)
SECTION                                                           PAGE

        3.6   MODEL PLANT PERFORMANCE ESTIMATES -
             RDF COMBUSTORS 	  3-37
             3.6.1   RDF SPREADER STOKERS 	   3-37
             3.6.2   EXISTING  FACILITIES EMISSIONS DATA 	   3-43
                     3.6.2.1   BIDDEFORD, MAINE	   3-43
                     3.6.2.2   RED WING.  MINNESOTA 	   3-43
             3.6.3   MODEL  PLANT BASELINE EMISSIONS 	   3-46
        3.7   RDF/WOOD CO-FIRED MWCs  	   3-46
        3.8   FLUIDIZED  BED COMBUSTORS 	   3-46
             3.8.1   EXISTING  FACILITIES EMISSIONS DATA 	   3-47
                     3.8.1.1   DULUTH, MINNESOTA	   3-47
                     3.8.1.2   LaCROSSE,  WISCONSIN 	   3-47
                     3.8.1.3   SUNDSVALL. SWEDEN 	   3-47
             3.8.2   MODEL  PLANT BASELINE EMISSIONS 	   3-48
4.0     REFERENCES  	   4-1
                                       VI

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                                    TABLES

TABLE                                                                   PAGE

1-1               11KB) MODEL PLANTS 	   1-2
1-2               11KB) BASELINE UNCONTROLLED EMISSIONS 	   1-3
2-1               GOOD COMBUSTION PRACTICES FOR MINIMIZING TRACE 	   2-3
                    ORGANIC EMISSIONS FROM MUNICIPAL WASTE COMBUSTORS
3-1               LARGE MASS BURN WATERWALL MWCs - 	   3-3
                    PERFORMANCE ASSESSMENT
3-2               SPLIT FLOW REFRACTORY MWCs - 	   3-17
                    PERFORMANCE ASSESSMENT
3-3               MASS BURN ROTARY WATERWALL MWCs - 	   3-21
                    PERFORMANCE ASSESSMENT
3-4               PITTSFIELD. MA, MODULAR EXCESS AIR - 	    3-25
                    MWC EMISSIONS TEST DATA
3-5               MODULAR STARVED AIR MWCs - 	   3-32
                    PERFORMANCE ASSESSMENT
3-6               PERFORMANCE TEST DATA. PRINCE EDWARD ISLAND MWC ...   3-35
3-7               RDF FIRED SPREADER STOKERS - 	   3-44
                    PERFORMANCE ASSESSMENT
                                       VI 1

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                                   FIGURES

FIGURE                                                                  PAGE

3-1               MASS BURN WATERWALL,  BASELINE DETERMINATION	  3-13
3-2               VOLUND SPLIT FLOW FURNACE 	    3-15
3-3               VOLUND SPLIT FLOW FURNACE WITH ROTARY KILN 	    3-15
3-4               PITTSFIELD. MA. MODULAR EXCESS AIR MWC 	    3-23
3-5               MODULAR EXCESS AIR.  BASELINE DETERMINATION 	    3-29
3-6               PRINCE EDWARD ISLAND MWC 	    3-34
3-7               MODULAR STARVED AIR,  BASELINE DETERMINATION 	    3-38
3-8               MERC - B&W BOILER DESIGN	    3-40
3-9               DETROIT STOKER RDF  METERED FEED SYSTEM 	    3-41
3-10              MID-CONNECTICUT CE  RDF FIRED MWC 	    3-42
                                       VI 1 1

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1.0         SUMMARY

      The EPA has completed an assessment of emission control  performance and
costs for  add-on  flue gas cleaning  alternatives,  and the results have  been
published  in  a technical  support document  as  part  of  the  lll(b)  emission
standards  development effort for new  municipal  waste  combustors  (MWCs).1
Twelve model  plants were  developed  in the study to  represent classes or groups
of combustors in the new  MWC  population that will be subject to the standards.
Baseline emission performance estimates were established for each of the model
plants.  A number  of  add-on  control  alternatives were applied  to  each model.
and  emission  reduction  and  cost  estimates  were  made  for  each   control
alternative.   This  report  provides  data  and  supporting  rationale   used  to
establish the baseline emission levels for  each  model  plant.   It  was assumed
in the study that all  new MWCs would  incorporate good combustion practice.

      Table 1-1  presents  design  and  operating data  for  the  12 lll(b) model
plants,  including  combustor  type, unit  size,  and  number  of  combustors  per
plant, and total plant size.  Baseline emission levels were established  for
three air pollutants:

      •     polychlorinated  dibenzo-p-dioxin and dibenzofuran  (CDD/CDF)
      •     carbon  monoxide  (CO)
      •     particulate matter (PM)

Baseline emission levels  are expressed  as flue  gas  concentrations  measured  at
the combustor or boiler outlet location, prior to treatment by add-on  flue gas
cleaning equipment.  Unless  otherwise noted, all emissions are normalized  to 7
percent 02-  Table 1-2 summarizes  the baseline emissions  that  were developed
for each model plant.  Baseline emissions for all  pollutants  were  established
using the available MWC  emissions  data  base or,  in cases where little or  no
data exist,  engineering judgment.

      The  goals of  this  report   are  to  present  the  data   and   supporting
rationale used to establish  the emission concentrations in Table 1-2.   Section
2.0 provides  background  information  describing the approach used  to specify
good  combustion  practice  recommendations, and  Section  3.0  provides  the
rationale used  to  establish the baseline  emission estimates for  each model
plant.
                                     1-1

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2.0         BACKGROUND

      On July 7, 1987, EPA published an Advance Notice of Proposed Rulemaking
(ANPR)  which  announced  EPA's  intent to  develop  new  source  performance
standards (NSPS) for new MWCs,  and  emission guidelines for existing MWCs under
the authority of Section  111 of  the  Clean Air  Act.2   In conjunction with the
ANPR. EPA  issued  operational  guidance  for  new mass burn waterwall,  modular
starved air. and refuse-derived-fuel  fired MWCs.  The operational guidance was
intended to  serve  as an  interim tool  to be used  in Best Available  Control
Technology (BACT) determinations for siting new MWCs  under  the  Prevention of
Significant Deterioration (PSD)  provisions of the Clean Air Act.  The guidance
specified that combustion controls  are  a necessary part of BACT for new MWCs.

      The background information that  led to the MWC  regulatory  decision  was
compiled and  published  in a Report  to Congress.3    As  part of  this  effort.
preliminary recommendations were made  defining  good  combustion  practices  for
new mass  burn waterwall,  modular  starved  air,  and RDF  fired  MWCs.4   Good
combustion practices  are expected  to minimize  emission of organics from  MWC
systems.  The original  recommendations  included three elements:

      •     Design
      •     Operation/Control
      •     Verification

The requirements to  satisfy these elements are:

      •     MWCs must be designed in  a  manner that minimizes air emissions.

      •     MWCs must be operated within an envelope dictated by the design of
            the combustion system, and  controls  must be in place  to  prevent
            operation outside of  the  established operating envelope.

      •     The performance of the combustion system must be  verified  by  way
            of compliance  testing  and through  continuous  monitoring  of  key
            design and operating  parameters, such as combustion air flows,  gas
            temperatures.  CO  flue  gas concentrations,  and  02   flue  gas
            concentrations.
                                     2-1

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The revised recommendations for good combustion  practices  used  in  this  report
are presented in Table 2-1.  The revised recommendations  are similar to those
provided in the  Report  to  Congress  with the exception of changes in some  of
the CO  emission limits and  the addition of a  recommendation  on PM control
device operating temperature  to address  low temperature formation of CDD/CDF.

      The good  combustion  practices  defined  in  this report are designed  to:
(1) maximize  in-furnace destruction of  organic  compounds,  and (2) minimize
conditions  that lead to low temperature formation  of  CDD/CDF.   Conditions
within the combustion process that satisfy the first goal  includes:

      •     Mixing of fuel  and  air  to  minimize  the existence  of  long-lived.
            fuel-rich pockets of combustion products.

      •     Attainment of  sufficiently  high  temperatures  in the  presence  of
            oxygen for the  destruction of hydrocarbon species.

      •     Prevention of quench zones or low temperature pathways  that will
            allow  partially   reacted  fuel   (solid  or gaseous) to  exit the
            combustion chamber.

All of  these conditions are interrelated;  successful destruction of  trace
organic species  requires that all  three conditions  be  satisfied in the MWC
system.  Mixing  is not  sufficient unless it  is  achieved  at  temperatures that
ensure  thermal  destruction of organic  compounds.   Completion  of the  mixing
process at  adequate  destruction  temperatures prevents escape of combustibles
through low temperature pathways.  Despite the continuing advancements made in
combustion  control,  perfect  mixing  will  never  be  achieved in a  combustion
system,  whether conventional  or waste  fired.   As a result, zero organic
emissions will not occur.  The goal  of good  combustion practice is to provide
the conditions that will minimize air emissions of concern.

      One  important  component  which  was  not   explicitly  included  in  the
original recommendations addresses the potential  for low temperature formation
of  CDD/CDF.  These  formation phenomena have been  measured at several  full
scale  MWCs. including those  at  Prince  Edward  Island; Pittsfield.  MA;  North
Andover. MA; and Pinellas County. FL.5.6.7.8
                                     2-2

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    TABLE 2-1.   GOOD COMBUSTION PRACTICES  FOR MINIMIZING TRACE ORGANIC
                EMISSIONS FROM MUNICIPAL WASTE COMBUSTORS
Temperature at fully
mixed height

Underfire air control
Overfire air capacity (not
an operating requirement)

Overfire air injector
design

Auxiliary fuel capacity
Downstream flue gas
temperature
1800°F  (982°C)
At least 4 separately adjustable plenums.
One each under the drying and burnout zones
and at least two separately adjustable
plenums under the burning zone (MB/WW).  As
required to provide uniform bed burning
stoichiometry (RDF)

40% of total air (MB/WW.  RDF)
80% of total air (MOD/SA)

That required for penetration and coverage
of furnace cross-section

That required to meet start-up temperature
and 1800°F  (982°C) criteria under part-load
conditions

<450°F «232°C) at PM control device
inlet
OPERATION/CONTROL
Excess air
Turndown restrictions


Start-up procedures

Use of auxiliary fuel
6-12% oxygen in flue gas (dry basis) (MB/WW
and MOD/SA).  3-9% oxygen in flue gas (dry
basis) (RDF)

80-110% of design - lower limit may be
extended with verification tests

On auxiliary fuel to design temperature

On prolonged high CO or low furnace
temperature
VERIFICATION
Oxygen in flue gas

CO in flue gas
Furnace temperature
Adequate air distribution

Downstream flue gas
temperature
Monitor

Monitor - 50 ppm on 4 hour average.
corrected to 7% 02 (MB/WW and MOD/SA).  100
ppm at 7% 02 (RDF)

Monitor - minimum of 1800°F  (982°C)  (mean)
at fully mixed height across furnace

Verification Tests

Monitor - <450°F «232°C) at  PM control
device inlet
 MB/WW - mass burn waterwall
 MOD/SA  - modular starved air
                                   2-3

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      The discovery  of CDO/CDF formation  in full  scale  MWCs has  prompted
research  in the  laboratory  to  identify  the  parameters  controlling  low
temperature CDD/CDF  formation  reactions.    Bench  scale  experiments  indicate
that,  under excess  air  conditions. CDD/CDF formation occurs on the surface of
fly ash  at temperatures  ranging  from  approximately  200 to  400°C  (392  to
752°F), with the maximum formation  occurring  near 300°C (572°F).  9  Conversely,
research  results have indicated that, when the same experiments were performed
in  an  oxygen-deficient  atmosphere,  dechlorination  of  CDD/CDF compounds
occurred.io  The current  thinking  regarding these findings  is  that  the
formation  process  may involve  catalytic  reactions  of  organic  precursor
compounds  with particulates  containing  metallic  species   such as  copper
chloride  (CuCl?).   The  bench  scale studies indicate that the rate of CDD/CDF
formation and/or chlorination is affected by  a number of  parameters, including
temperature,  residence  time,  catalyst  effects,  carbon  content,   oxygen
concentration,  and  moisture.    Results  from  these   experiments  provide
information which  can  be transferred to  full  scale  MWCs in  order to develop
control  strategies  for  minimizing CDD/CDF formation.

      Although  many  strategies for  minimizing the reactions (e.g.,  catalyst
poisons)  remain to be  investigated, it  appears at this  time that an initial
control  strategy is to minimize the particulate  matter  concentration  and the
flue gas  residence  time at  temperatures  were the rate of CDD/CDF  formation is
highest.   If organic precursor materials leaving  the combustor are minimized
and if flue gas retention  times  and  PM concentrations can be minimized in the
200-400°C  (392-752°C)  temperature range,  it appears that  the formation  process
can be minimized.   Many existing MWCs  currently  operate flue gas  cleaning
equipment (ESPs) in this temperature window.   The  increased gas  residence time
and PM concentrations  which  occur  in  the  ESP may  be  the  primary  cause of
CDD/CDF formation,  leading to increased  emissions  in the stack.  Recent data
from  a  full  scale  MWC confirm  that  high  efficiency ESPs  operating  at
temperatures below  250°C actually provide significant CDD/CDF removal.11 Based
on  these  considerations,  a new component of good  combustion  practices was
developed.   The  recommendation is  to maintain  PM control  device  inlet gas
temperatures below  232°C (450°F).
                                     2-4

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3.0         MODEL PLANT PERFORMANCE  ESTIMATES - MASS BURN COMBUSTORS

      The following sections discuss the data and provide the  rationale  used
to establish the baseline emission  values in Table  1-2.   The  subsections are
organized according to  model  plant  combustion  technology.   The data  used  to
establish baseline emissions for each model plant are compiled  from  emission
tests performed at some of  the  newest plants in  the existing  MWC  population.
The emission tests  can be  separated  into three distinct categories:

      1.    Compliance tests with sampling  performed at  the  stack, downstream
            of flue gas cleaning equipment.   In most cases these data  were
            generated under  optimal  operating  conditions at  or  near  design
            steam load.  In many cases process data  such  as temperatures and
            airflows  were  not  recorded during testing.

      2.    Compliance tests with sampling performed concurrently at the inlet
            and outlet  of the  flue  gas  cleaning equipment.   In  most  cases.
            limited process  data were  recorded,  and  the  combustor  operated  at
            or near design steam load.

      3.    Parametric tests involving multi-point sampling under a variety  of
            combustor and/or flue gas cleaning  device  operating  conditions.
            Process data are usually well documented in these test  reports.

      The emissions data used in this analysis are  presented in both  tabular
and graphical  form.   The  data  tables  present  multiple  run  averages  reported
for each test  facility.  Data measured in a parametric  test are averaged and
presented  separately for each   parametric  operating condition.   Combustor
design and operating data are also  included in the  data summary tables.  The
data graphs present the emission levels  for each sampling run,  along  with  an
average value for each testing condition.

      Test  reports that  include emissions  measured upstream of  flue gas
cleaning equipment provide  the  best data to evaluate combustion  conditions.
As a  result,  emission tests in  categories 2 and 3  are  the  primary focus  of
this  analysis.   In  some cases, data  measured in  the stack  also  provide
information  related  to combustion  conditions.   When these data  offer  some
insight  into combustion  conditions experienced  during testing, they  also
                                     3-1

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provide insight  into  combustion  conditions  experienced during testing;  they
are also included in the discussion of baseline emissions.

3.1         Conventional Mass Burn Waterwall  MWCs

      There are three  conventional mass burn waterwall  models included in  this
analysis.   An inventory  of  planned and  projected MWCs  indicates  that the
majority of  new facilities  subject  to the  lll(b) NSPS will  use mass  burn
technology.12   The three  model  plants  are  representative  of the projected
population  of MWCs. comprising two combustors at 100 tpd (91  Mg/day) each; two
combustors  at 400 tpd  (364 Mg/day)  each;  and  three  combustors  at 750  tpd  (681
Mg/day) each.

3.1.1       Emissions  Data  for Existing Facilities

      The  baseline emissions are established  based on review of available
emissions  data  from  some of  the  newest mass burn  waterwall MWCs in the
existing population.   These units are considered to be  representative of the
planned and projected  MWC  population as of September 1988.   Data are available
for  facilities  using  Von Roll. Martin.  Detroit  Stoker,   and  Riley Takuma
technologies.  These  four  system designs  comprise more  than  85 percent of the
existing mass burn waterwall  MWCs,  and each  manufacturer  is  expected  to
continue to be represented in the new MWC population.  Descriptions of generic
design and operating features associated with each of  the system  designs are
included in EPA's Report to Congress on Municipal Waste Combustion.4

      Table  3-1  presents  a  summary  of  emissions  data for  the  facilities
included  in  this  analysis.   Also  included  in   Table 3-1  is   information
detailing  the design and  operation of  each  facility  relative  to  the  good
combustion practice criteria  which was developed for mass burn waterwall  MWCs.
When  available,  combustor operating conditions  are  presented   as  reported
during the actual testing  period.   In cases  where  process operating  data are
not available, information has been  supplied for a  facility as reported in the
Clean Air Act  Section 114  questionnaire  responses which were submitted to EPA
by each existing facility.
                                     3-2

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      TABLE 3-1.   LARGE MASS  BURN WATERWALL MWCS - PERFORMANCE ASSESSMENT
                                     PAGE 1 OF 4
FACILITY
NUMBER OF UNITS - Flue gas cleaning equipment (FGC)
UNIT SIZE, tpd (Mg/day)

UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)

CONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
GOOD COMBUSTION
PRACTICE RECOMMENDATIONS
                                Mi 11 bury. MA
                                2 - SD/ESP
                                750 (682)
                                170
                                38
                                NA
                                59.2
FACILITY DESIGN
AND OPERATING CONDITIONS
Temperature at fully
mixed height

Underfire air
Overfire air capacity
(not an operating
requirement)

Overfire air injector
design

Auxiliary fuel  capacity
Exit gas temperature
OPERATION
Excess air

Turndown
Overfire air


Start-up procedures


Auxiliary fuel use


VERIFICATION
02 levels

CO

Temperature


Air distribution

Exit gas temperature
1800°F (982°C) mean
At least 4 plenums along
grate length

40% total air
Complete penetration/
coverage

As required to achieve
temperature limits
during start-up

<450°F (232°C) at PM
control device inlet
6-12% 02 (dry)

80-110% design load
Penetration and coverage
of furnace cross section

Auxiliary fuel  to design
temperature

High CO. low temp:
start-up/shutdown
Monitor

Monitor «50 ppm at 7% 02)

Monitor


Monitor

Monitor
1500°F (816°C)  at
superheater inlet

5 plenums along
grate length

At least 60% total  air
3 rows (2 front. 1 rear)
Gas - 40% load
435°F (224°C)
10.2% 02

Baseloaded - 100* ±3%;
66X minimum

40-50% total air
Gas - 1500°F (816°C) at
superheater inlet

Start-up/shutdown
Yes

Yes

Superheater inlet/
outlet

OFA, UFA pressures

Yes
                                          3-3

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      TABLE 3-1.   LARGE MASS  BURN WATERWALL MWCS  - PERFORMANCE ASSESSMENT
                                     PAGE  2 OF 4
FACILITY
NUMBER OF UNITS - FGC
UNIT SIZE, tpd (Mg/day)

UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)

CONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
Pinellas County.  FL
3 - ESP
1050 (954)
69
4
225
132
FACILITY DESIGN
AND OPERATING CONDITIONS
Tulsa. OK
3 - ESP
375 (341)
36
22

FACILITY DESIGN
AND OPERATING CONDITIONS
Temperature at fully
mixed height

Underfire air
Overfire air capacity
(not an operating
requirement)

Overfire air injector
design

Auxiliary fuel capacity

Exit gas temperature

OPERATION
Excess air


Turndown

Overfire air

Start-up procedures

Auxiliary fuel use

VERIFICATION
02 levels

CO

Temperature


Air distribution


Exit  gas temperature
1700°F  (927°C)
5 plenums along
grate length

At least 25% total  air
2 rows (1 front, 1 rear)


None

450-550°F (232-288°C)


8-10% 02 at full load
9-11* 02 at minimum load

70-90% design load

25% of total air

No auxiliary fuel

None


Yes

No

Furnace roof, super-
heater inlet/outlet

OFA pressure, UFA
damper settings

Yes
1400-1600°F (760-872°C)
at superheater inlet

5 plenums per grate
run

At least 40% total air
NA


None

375-515'F (191-263°C)


7-12% 02


72-100% load

20-40% total air

No auxiliary fuel

None


Yes

Yes

NA


OFA. UFA pressures


Yes
                                          3-4

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      TABLE 3-1.   LARGE MASS BURN WATERWALL  MWCS - PERFORMANCE  ASSESSMENT
                                     PAGE 3 OF  4
FACILITY
NUMBER OF UNITS - FGC
UNIT SIZE, tpd (Mg/day)

UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)

CONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
Marion County. OR
2 - SD/FF
275 (250)
43
18
205
1.39
FACILITY DESIGN
AND OPERATING CONDITIONS
Alexandria, VA
3 - FI/ESP
375 (341)
53
18

FACILITY DESIGN
AND OPERATING CONDITIONS
fiESJLGl
Temperature at fully
mixed height

Underfire air
Overfire air capacity
(not an operating
requirement)

Overfire air injector
design

Auxiliary fuel  capacity

Exit gas temperature

OPERATION
Excess air

Turndown

Overfire air

Start-up procedures

Auxiliary fuel  use

VERIFICATION
02 levels

CO

Temperature


Air distribution

Exit gas temperature
1400-1600°F  (760-872°C)
at superheater inlet

5 plenums per grate run
At least 40% total  air



3 rows


Gas - 30% load

392°F (200°C)


7-12% 02

75-105% design load

20-40% total air

Gas to 1800°F  (982°C)

Start-up/shutdown


Yes

No

Middle and top of
furnace

OFA. UFA pressures

Yes
1400-1600°F (760-872°C)
at superheater inlet

5 plenums along grate
length

At least 40% total air
2 rows


Oil  - 25% thermal load

375-505°F (191-263°C)


7-12% 02

80-100% load

20-40% total air

On oil to 1400°F (760°C)

Start-up/shutdown


Yes

Yes

Furnace exit
(superheater inlet)

OFA. UFA pressures

Yes
                                          3-5

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      TABLE 3-1.   LARGE MASS  BURN WATERWALL MWCS  -  PERFORMANCE ASSESSMENT
                                     PAGE  4 OF 4
FACILITY
NUMBER OF UNITS - FGC
UNIT SIZE, tpd (Mg/day)
UNCONTROLLED EMISSIONS
COD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)
CONTROLLED EMISSIONS
CDD/COF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
Commerce.  CA
1 - SD/FF
350 (318)
27
4620
1.70
16
FACILITY DESIGN
AND OPERATING CONDITIONS
Olmstead County. MN
2 - ESP
100 (91)
31-54
FACILITY DESIGN
AND OPERATING CONDITIONS
Temperature at fully
mixed height
Underfire air
Overfire air capacity
(not an operating
requirement)
Overfire air injector
design
Auxiliary fuel capacity
Exit gas temperature
OPERATION
Excess air
Turndown
Overfire air
Start-up procedures
Auxiliary fuel use
VERIFICATION
02 levels
CO
Temperature
Air distribution
Exit gas temperature
1700°F (926°C)
at superheater inlet
6 plenums (2 per grate
length)
40% total air
2 front, 2 rear. 1 side

Gas - 100% load
480°F (249°C)

10% 02 ±2%
70-101% design load
20-40% of total air
On gas
Start-up/shutdown

Yes
Yes
Yes
OFA. UFA  pressures
Yes
1700°F (926°C)
furnace gas exit
3 plenums along
grate length
At least 35% total air
3 rows

Gas - 10% load
425°F (218°C)

7% 02
60-100% load
35% total air
On gas
Start-up/shutdown

Yes
Yes
Yes
OFA. UFA pressures
Yes
                                          3-6

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3.1.1.1     Millburv.  Massachusetts

      Wheelabrator Environmental  Systems  is the  U.S.  licensee of  Von Roll
technology.   One  of  the  newest Wheelabrator  plants  in  operation  is  the
Millbury,  MA  Resource Recovery  Facility,  which  includes  two 750  tpd (682
Mg/day) combustors.  Each  unit is equipped with a spray dryer  and an  ESP.  The
facility began operating  in  1987 and underwent compliance testing  in early
1988.   In  addition  to performing  stack testing  for  compliance  purposes,
emissions  were measured  at  the  spray dryer  inlet  location.   Five CDD/CDF
emission samples  were  gathered at the spray dryer inlet location at Unit #2.
and average emissions  were  170 ng/dscm CDD/CDF.*3  Individual  runs ranged from
140 to 210 ng/dscm.  Average  CO emissions were 38 ppmv (4-hour average)  during
the  five  test runs.   The average  gas  temperature  at the  inlet  sampling
location ranged from 429 to 442°F (221 to 228°C) during the five runs.

      An assessment of the combustor design at Millbury  indicates  that  the
majority of design elements are  in  place to  provide  good combustion.   Furnace
temperatures are  measured  at the inlet and outlet  of  the  superheater.  The
thermocouple at  the superheater  inlet location is  approximately 35 feet (10.7
m) above the  last point  of  overfire air injection,  and a  typical   operating
temperature at  this  location  is  1500°F  (816°C).    Millbury  has  five
individually  controllable underfire air plenums  along the length  of  the
reciprocating  grates.   One design feature at Millbury that differs from older
Von Roll systems  is the overfire air capacity.   The overfire air  system has
the capacity to supply 60  percent of  total  combustion air.  The Millbury units
operate with 40-50 percent of total  air supplied  as overfire air.   Many  Von
Roll facilities constructed  prior to Millbury operate  with  30-40  percent  of
total airflow  as  overfire.

      The majority of  operation/control and verification elements representing
good combustion  practice are also in place at Millbury.  The  units  typically
operate at full  capacity  generating electricity,  so  low load  operation  is
infrequent.   All  the recommended  monitoring  procedures  are  in   place  at
Millbury.

3.1.1.2     Pinellas County.  Florida

      The  Pinellas County  MWC  consists of  three  1050 tpd (954  Mg/day)
combustors, with  Martin stokers  and three-field ESPs.  The  #1  and  #2 units

                                     3-7

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started up in 1983. and #3 commenced operation  in  1986.   Six  ESP  inlet/outlet
CDD/CDF emission tests were conducted at Unit #3  in  February  and  March  1987.
Average inlet emissions were 69 ng/dscm and average  CDD/CDF emissions in  the
stack were  132  ng/dscm.8   Average  flue gas  temperatures at  the ESP  inlet
location ranged from 523  to 553°F (273 to 289°C).  Average PM  and CO values
measured  at the  ESP  inlet  were 0.98 gr/dscf  (225 mg/dscm) and  4  ppmv,
respectively.   The  CO emissions were measured  concurrently with  CDD/CDF
testing, which was 3 hours' duration.  Boiler #3  operated between 88 percent
and 91 percent rated capacity  during the  six test runs,  and  QZ concentrations
varied  from  6.9  to 7.7  percent  (wet basis).  Average  furnace temperatures
reported  during testing varied  from 1824°F  (996°C)  to  1923°F  (1051°C).
measured in the upper  furnace.   Underfire  and overfire  air plenum pressures
were  recorded  and  were  fairly  consistent   during  all  of the  runs.   Actual
airflow splits  are  not  available.

      The design of the Pinellas County plant meets  the majority  of  criteria
required  for good combustion.   However.   Pinellas County  does not  have
auxiliary fuel  burners.  In addition,  the normal  ESP  operating  temperature  is
approximately  500°F  (260°C).    The  ESP  temperature   is  assumed  to  have
contributed to the  increased CDD/CDF concentrations measured  at the ESP outlet
location.  Based on the emission test  results (low organics and CO levels),  it
is concluded that  the unit achieves  good mixing.   The three units  at  Pinellas
County are operated on a manual  combustion  control  scheme, with the exception
that  steam  production  rates are automatically controlled.   The  majority  of
mass  burn  waterwall   MWcs  are  equipped  with  fully  automatic  combustion
controls.  A manual control  scheme may allow greater  potential  for combustion
upsets  to occur.   With  the  exception  that  the units  do  not  monitor  CO
continuously,  Pinellas  County has  all  of the verification measures in  place to
ensure good combustion  practices are maintained.

3.1.1.3     Tulsa.  Oklahoma

      Emissions  data from two  other  facilities  using  Martin designs were also
used to establish  baseline emission  factors  for the model plant.  The  first of
these is the Tulsa, OK facility,  which consists of three 375  tpd  (341 Mg/day)
combustor units.  The facility  began operating  in  1986.   Each  of  the  units  is
equipped with  an  ESP.   The ESP  inlet gas  temperature typically  varies from
375 to  515°F (191 to 268°C).  Available emissions  data gathered  for compliance
purposes  indicate  average CDD/CDF  emissions of 36 ng/dscm at  the  stack

                                     3-8

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location.14   The flue gas temperature  during  testing  was not included  in  the
report.  Emissions of CO averaged  22 ppmv  at  Unit  #1  and 27 ppmv at Unit #2.
The CO data were gathered separately from the CDD/CDF data, and are presented
as 1-hour averages.   There  are no process data  available  in  the test report to
use in evaluating the combustor operating conditions.  With  the exception that
Tulsa does not have auxiliary fuel, all  of  the  requirements  of good combustion
are assumed to be achieved  at this  facility.

3.1.1.4     Marion County.  Oregon

      The Marion County, OR  MWC consists  of two 275  tpd (250 Mg/day)  Martin
combustors equipped with spray dryers and fabric filters.  The units commenced
operation in  1986.   During  stack  compliance  testing  in September  1986.  EPA
performed  three  sampling  runs  at the boiler  outlet   (spray  dryer  inlet)
location.  Two of the three  sampling runs were  invalidated,  but the results of
the one successful  run indicated an inlet CDD/CDF emission rate of 43 ng/dscm.
In addition, inlet particulate emissions were 0.89  gr/dscf (2050 mg/dscm). and
CO emissions were 18 ppmv (4-hour average).15

      Process data were recorded during the compliance test at Marion County.
The steam  load  was 97  percent of design  load  during CDD/CDF testing.   Gas
temperatures measured in the middle of the first furnace pass averaged 1741°F
(949°C),  and  the average economizer  outlet temperature was 392°F  (200CC).
Average exhaust gas oxygen  concentrations  were 9.5 percent,  and the estimated
overfire/underfire air ratio was 25/75.  The Marion County units are equipped
with auxiliary fuel  burners that can provide 30 percent  of thermal  load.  The
units do not have continuous  CO monitors.

      EPA gathered an additional 14 unabated CDD/CDF samples at Marion County
in February 1987.  During all of the sampling runs, the boiler was operated at
normal, full  load  conditions.   Analysis was completed on  seven  of the runs.
Four  of  the  seven  samples  had acceptable  spike  recoveries  and were full
traverse samples.  Three of  the seven runs  either were single point samples or
were  invalidated due  to poor recoveries.   The CDD/CDF values  from the valid
test runs ranged from 56 to  116 ng/dscm. with an average  value of 99 ng/dscm.is
                                     3-9

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3.1.1.5     Alexandria.  Virginia

      The third new Martin  facility. Alexandria, VA. consists of three 375 tpd
(341 Mg/day) units that began operating in  1987.   The  system design includes
in-furnace  lime  injection  for  acid gas  control,  and  ESPs for  PM control.
Results of compliance testing performed at Unit #1  in  December 1987 indicated
a three-run average of 53 ng/dscm CDD/CDF and  18 ppmv  of  CO (3-hour average)
in the  stack.17   Limited process  data are  included  in the  compliance test
report.  The boiler  reportedly  operated at between 98  and  99 percent design
steam  load  during the  three runs,  and average 62  concentrations  were 9.5
percent.  The furnace temperature was  measured at an  unspecified furnace exit
location with an unshielded thermocouple.   The average  temperature during the
three runs was 1651°F (899°C),  1664°F (907°C). and 1642°F (894°C).   The test
report authors  state that the measurement  method "should be regarded as being
relatively accurate;  i.e.,  lower than  the  actual temperature by approximately
150-200°F,  but  precise."   The  average stack  temperature  was reported  to  be
342°F (172°C) while sampling, so  it is judged  that the ESP temperature was
below 450°F  (232°C).  Although the existing data base does  not provide a  basis
for  estimating the  effect of  dry  lime  furnace  injection  on CDD/CDF.  the
emission levels are typical  of  those measured  at other Martin systems, that do
not use acid gas controls.

      The facility is judged to  satisfy the majority of criteria  included in
the  good  combustion  practice recommendations.   The  gas temperatures  at the
superheater inlet are reported to vary from 1400°F  (760°C)  to 1600°F  (871°C).
The  plant has  an  auxiliary fuel  source (oil),  and the  firing capacity is 25
percent of boiler load.

3.1.1.6     Commerce. California

      The Commerce.  CA.  MWC consists  of  one 350 tpd  (318  Mg/day) unit with
Detroit Stoker grates and a Foster Wheeler  boiler.   The unit is equipped with
a spray dryer/fabric filter.   Commerce was  also the  first MWC in  the U.S. to
use thermal  de-NOx controls.  The facility underwent an  emissions  test  in 1987
for  compliance  purposes.   The  CDD/CDF  emissions data  were measured  according
to  the  draft  California Air Resources  Board  (CARB) Modified Method 5  (semi-
VOST)  protocol.   Two test  runs  were conducted at  the stack while  burning the
largely commercial waste normally received  at the facility.   A  third test  run

                                     3-10

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was conducted with  simultaneous measurement at the boiler exit  and  stack while
burning a residential  refuse brought  in  from  Long  Beach.  CA. specifically for
the test.   Steam  load was reduced from full  load  to  80 percent of capacity
during the inlet/outlet sampling.   During  the one  test  run  that  was  conducted
at the spray dryer  inlet.  27  ng/dscm  CDD/CDF was  measured.   Inlet PM and CO
emissions were  1.56  gr/dscf  (3590 mg/dscm)  and  16 ppmv  (1-hour average),
respectively.18

      The amount of process data  included  in the emissions  test report is
fairly limited.   Steam load varied from 80 to 103 percent of capacity during
the test.   The  thermal  de-NOx  system was  operational  throughout the testing
period except  for   one  test run when the NOX levels  were  measured without
ammonia injection.   This  control system demonstrated NOX reduction  in excess
of 40 percent.   The report contains no information on combustion  air  operating
levels.

      The Commerce  facility  has  all  of  the design  components  of  good
combustion in place.  It  is judged that the  1700°F (927°C)  superheater  inlet
temperatures correspond  to a temperature at the fully mixed  height  which meets
the  good combustion  recommendations.   The  operation  of  the facility  is
maintained  by  a   fully  automatic  control   system.    The  unit  generates
electricity,  operating  at full  load  whenever  possible.    All  of  the
verification  measures are  in  place to monitor  continuous performance  and
ensure good  combustion.

3.1.1.7     Qlmstead County. Minnesota

      The last  mass burn waterwall MWC included  in this discussion  is  the
Olmstead  County,  MN  facility,  which began  operating  in  March  1987.   The
facility  consists  of  two 100 tpd  (91  Mg/day) Riley-Takuma MWCs.   Although
CDD/CDF emissions  data are  not  available  for the  facility  at  this time,  the
plant does monitor  CO  continuously, and average reported values  are 31-54 ppmv
at 7  percent 02 (averaging  time not reported).19   The testing  program at
Olmstead  County was a characterization  test to determine  the operating  and
emissions performance  of  one of the units prior to undertaking  a  gas  co-firing
performance evaluation.   Sampling was  performed  at multiple  points  in  the
furnace for  0?.  COg, CO, and NOX.  A  series  of  21 tests were  performed with
variations  in  load,  combustion  airflow, and  air distribution.   Furnace

                                     3-11

-------
temperatures were measured  by  suction pyrometry during each test.  Temperature
profiles were also measured at the economizer outlet location.

      One of the main  conclusions in the study was that the use  of  overfire
air contributes to a reduction in CO emissions  and  at  the same increases NOX
levels.  The highest  NOX emissions (191 ppmv) and the lowest CO emissions (31-
54 ppmv) occurred when  overfire air was  operated at 33  percent  of total  air,
and the lowest NOX (70  ppmv) and  highest  CO (123 ppmv)  occurred when overfire
air was turned off.

      The majority  of  good combustion  elements are  in  place at  Olmstead
County.  However, there  are only three plenums  along the grate length,  which
is typical  for smaller  capacity systems.  The auxiliary fuel capacity is  lower
than specified by the guidelines  (10 percent versus  60  percent  of full  load).
but this will  not  affect baseline  operating conditions.   The  low economizer
exit gas temperatures [typically  425°F  (218°C)] should minimize the potential
for formation of CDD/CDF in the ESP.

3.1.2       Model  Plant Baseline  Emissions

      The data  used  to  establish  baseline CDD/CDF emissions  for mass  burn
waterwall  model plants  are  plotted in Figure 3-1.  The data include values for
each  individual  sampling   run.   Facility  averages are  also  plotted  when
multiple runs are available.  Five of the seven data sets include uncontrolled
emissions measured upstream of flue  gas cleaning equipment.  Average emissions
range  from  27  ng/dscm  (one  run)  at  Commerce to  170  ng/dscm  (5  runs)  at
Millbury.   Two of the  data sets  consist of controlled  emissions  measured in
the  stack  downstream of an  ESP.   Average  emissions  reported  for  these two
plants  (Tulsa  and Alexandria) are  36  ng/dscm and 53  ng/dscm.  respectively.
The  ESP  operating temperature was  not specified for  Tulsa  during  the  test
runs.   The  stack temperature at  Alexandria was reported  to  be 342°F (172°C)
during  testing,  so  it  is  assumed that  the ESP operated  at or  below  400°F
(204°C),  and that some  amount  of CDD/CDF  removal occurred in the ESP.

      The available  uncontrolled data  indicate  that three  of the four plants
tested achieved CDD/CDF emissions  below 100  ng/dscm.  However, two of the data
sets  consist  of a  single  sampling  run.  and  these  single  runs  may  not
accurately  represent an average CDD/CDF  emission  level.   This  is  verified by
                                     3-12

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-------
the multiple runs obtained at Marion County in 1987.  Based on the  available
data in Figure 3-1.  it  is  assumed that all seven of the facilities are able to
achieve an uncontrolled baseline emission level of 200 ng/dscm COD/CDF.  There
are  insufficient data  available  to  establish different  baseline  emission
levels for each of the mass burn waterwall  model  plants  based  on  manufacturer
or size.  Therefore.  200 ng/dscm was selected as a baseline emission  level  for
all three mass burn  waterwall model plants.

      The available  data  on  CO emissions and  uncontrolled  PM emissions  are
relatively consistent  for  the  mass  burn waterwall  population.   The  CO data
reported for  the seven  plants included in this analysis varied from 4 ppmv  (3-
hour average) at  Pinellas  County  to  43  ppmv (unspecified averaging  time)  at
Olmstead County.  Tulsa and Commerce report CO levels less than 30 ppmv with a
1-hour averaging time.   Alexandria reports 18 ppmv on a 3-hour averaging time.
and Marion County reports 18 ppmv on a 4-hour averaging time.   All  of  the
facilities tested can achieve 50 ppmv  on a  4-hour  average, which  was selected
as a baseline value.   Uncontrolled particulate emissions will vary  according
to boiler design, air  distribution,  and waste characteristics.   For example,
facilities that operate with  high  underfire/overfire air  ratios or relatively
high excess air  levels may entrain  greater  quantities of PM  and  have higher
uncontrolled  emissions.    Boilers  with  multiple  passes  that  change  the
direction  of  flue  gas flow in the  convective  section may  remove  greater
quantities of entrained PM  prior  to entering flue gas cleaning  equipment.
Lastly, the physical properties of waste  being fed  to a unit may impact  the
amount  of PM  that   becomes  entrained.    Despite these factors,  a  nominal
uncontrolled  PM emission  rate from a mass  burn waterwall  MWC  is  2 gr/dscf
(4600 mg/dscm).  The available  data  for  the  units  discussed  above ranges from
0.89 gr/dscf (2050 mg/dscm) at  Marion County to 1.56 gr/dscf (3660 mg/dscm) at
Commerce.   It  is anticipated that  all new  mass   burn  waterwall  MWCs will
achieve a baseline uncontrolled  PM emission  rate of  2 gr/dscf (4600 mg/dscm).

3.2         Split Flow Refractory MWCs

      The  mass  burn  refractory  model  plant  is  assumed to  use the  Volund
combustion technology.   The  Volund  combustor  is   characterized  by  a  split
furnace flow design  which  may be configured  in two different ways (see Figures
3-2 and 3-3).   The  Volund  systems are designed either with  a  refractory arch
which  splits  the flow, or with a  flue  gas  overpass and a rotary kiln.   The
kiln  arrangement  is  generally  used  for  medium and  large size units [greater

                                     3-14

-------
       Figure 3-2.  Volund Split Flow Furnace
Figure 3-3.   Volund Split Flow Furnace with Rotary Kiln
                           3-15

-------
than 150 tpd (136 Mg/day)] while the refractory  arch  is  used  for  small  units.
If  locally  available waste is  high in moisture,  difficulty achieving  good
burnout is possible  and the rotary  kiln  is  preferred.   The kiln exposes the
waste to  increased  residence times  at  high  temperatures and oxygen content.
resulting in improved burnout.

3.2.1       Emissions Data  for Existing Facilities

3.2.1.1     McKav Bav.  Florida

      McKay Bay,  FL. is one operating facility in the U.S. which  uses the new
Volund technology.   The facility consists of four 250 tpd (227 Mg/day)  units
which use  the  rotary kiln configuration.   The  plant  commenced operation in
1985,  and compliance testing  was performed  on  the  four  units  in   1986.
Uncontrolled particulate emissions averaged 1.86 gr/dscf (4350 mg/dscm)  and CO
emissions  averaged  32 ppmv (individual  units achieved  30,  35. 32.  and 32
ppmv).14   Emissions  of  CDD/CDF were not reported  for this plant.   Very limited
process data are  available  for the test.

      Table  3-2  summarizes  recommended  good combustion  practices  for
refractory wall  MWCs using  the  split  flow design.   One specific requirement
that differs between refractory  wall MWCs and waterwall  MWCs  is the  excess air
operating range.   Refractory wall  MWCs  typically  operate at higher  excess air
levels than  waterwall  MWCs due  to the need  to  provide  furnace cooling.  An
evaluation of available information on the McKay Bay, FL. facility  indicates
that  several  of  the  good  combustion  practice design criteria  are not  met,
including requirements for auxiliary fuel use and  for exit gas  temperatures.
The  ESPs  at McKay  Bay typically operate  near  550°F (288°C). so  potential
exists for  CDD/CDF  formation to occur  in the control devices.   In  addition.
the  plant  does  not  monitor CO.   The combustion control  scheme  is based on
steam flows, temperatures,  and  air  flows.   The secondary air level controls
the  temperatures  exiting the  furnace.    Although  combustor  operating
temperatures are  not specified,  it  is  assumed  that the  units  meet the
temperature  requirements for good combustion.  The McKay  Bay  units  typically
operate at 60-135 percent  excess air.
                                     3-16

-------
         TABLE 3-2.   SPLIT  FLOW REFRACTORY MWCS - PERFORMANCE  ASSESSMENT
FACILITY
NUMBER OF UNITS - FGC
UNIT SIZE, tpd (Mg/day)

UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)

CONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
GOOD COMBUSTION
PRACTICE RECOMMENDATIONS
                                McKay Bay. FL
                                4 - ESP
                                250 (227)
                                Not Available (NA)
                                32
                                4280
                                NA
FACILITY DESIGN
AND OPERATING CONDITIONS
DESIGN

Temperature at fully
mixed height

Underfire air
Overfire air capacity
(not an operating
requirement)

Overfire air injector
design

Auxiliary fuel capacity
Exit gas temperature

OPERATION
Excess air

Turndown

Overfire air
Start-up procedures


Auxiliary fuel use


VERIFICATION
02 levels

CO

Temperature

Air distribution

Exit gas temperature
1800°F (982°C) mean
At least 4 plenums along
grate length (not
including kiln)

40% total air
Complete penetration/
coverage

As required to achieve
temperature limits
during start-up

<450°F (232°C)
6-14% 02 (dry)

80-110% design load

Penetration and coverage
of furnace cross section

Auxiliary fuel to
1800°F  (982°C)

High CO. low temp;
start-up/shutdown


Monitor

Monitor (<100 ppmv at /% ()?))

Monitor

Monitor

Monitor

           3-17
NA


3 plenums



Sidewall air



Quantity not specified


None



550°F (288°C)


8-12% 02

Unknown

Unknown


No auxiliary fuel


No auxiliary fuel



No

No

Yes

NA

NA

-------
3.2.1.2     Nvkoping.  Denmark

      A second set of emissions  testing  data  is  available  from  a  Volund  plant
located  in  Nykoping.  Denmark.20   This  facility  includes two units  with a
combined capacity of 168 tpd  (153 Mg/day).  The units, which began  operating
in 1983, burn a mixture of domestic and  non-hazardous  industrial  waste.   Each
unit  uses  the  refractory arch  split  flow configuration  rather  than a
refractory kiln.   The majority of the combustion gases  pass  above the  furnace
arch and are mixed with gases  from the burnout grate.   The units  are equipped
with  waste  heat  boilers.  ESPs.  and  automatic  combustion controls which
regulate furnace  temperatures  and  steam production  rates.

      The  emissions  testing  performed  at Nykoping  included  CDD/CDF stack
sampling during start-up, normal operation, and  variable boiler loads.   Flue
gas oxygen  concentrations  were  maintained between 7.4  and  9.7 percent,  and
average furnace temperatures were approximately  940°C (1724°F).   Temperatures
were measured  above the  transverse  arch  where the flow streams converge  and
mix.   Although the data are  not  tabulated for  all runs,  a typical  CDD/CDF
emission level was reported to  be 246.5 ng/Nm3 (sum of all  CDD/CDF  corrected
for spike recoveries).20  Graphical presentations of CO emissions  are included
in the  test  report,  but  no values are tabulated for specific  sampling  runs.
It appears from the graphs that  the units  operate  at CO levels  between 50 and
200 ppmv.  The authors of the test report  concluded from the emission  results
that  mixing  in the  furnace has  an  important  impact   on  the  destruction  of
CDD/CDF. and that concentrations of  CO  in the  flue  gases  at  well designed
plants  can be used  as a  parameter  for monitoring and control.   There  is
insufficient information available to assess the design and operation of the
Nykoping  unit  with the  good  combustion practice  criteria,  but  the  furnace
temperatures  and oxygen levels  reported  are indicative  of good combustion
conditions.  The  ESP  operating temperature was not reported at  Nykoping.

3.2.2       Model Plant Baseline Emissions

      Based  on the limited data  available from the McKay  Bay and Nykoping
MWCs. a baseline emission level  of 300 ng/dscm CDD/CDF  was  established  for the
model  plant.   Although all four  of  the  combustors  at  McKay Bay achieved  CO
emissions  lower  than  50  ppmv, a  graphical  presentation  of CO  data  from
Nykoping  indicates  slightly  higher  levels  during optimum  combustion

                                     3-18

-------
conditions.  Therefore,  baseline  CO  emissions  were established at 100 ppmv.
The limited data available from the McKay Bay units supports an uncontrolled
particulate emission  level  of 2 gr/dscf (4600 mg/dscm).

3.3         Rotary  Waterwall MWCs

      The O'Connor  Combustor  Corporation was  purchased by  Westinghouse in
1986.   The Westinghouse/O'Connor system design is unique;  it  includes a  rotary
waterwall cylinder consisting of alternating watertubes and perforated steel
webs (i.e. a cylindrical, perforated membrane waterwall).  Waste is  fed  to the
combustor by a  dual  ram feeder,  and  preheated combustion  air is delivered
through  the perforated  webs  by way  of  six windboxes  located beneath  the
barrel.  The rotary section terminates within a  waterwall boiler where  bottom
ash is  discharged  and combustion  gases  pass  through the boiler  to produce
steam.

       The first O'Connor  MWC  in  the  U.S.  commenced  operation in 1980  in
Gallatin, TN.21   Since Westinghouse purchased the O'Connor  system, they have
started  up  two  new  facilities  (Bay County.  FL,  and Dutchess County, NY).
Several  more  plants  are in planning,  permitting, or  construction stages.
Parametric testing results  obtained from Bay County and Gallatin have  influ-
enced  some  aspects  of Westinghouse's approach  to  designing new facilities.
For example,  the  Gallatin facility  originally included  rows of overfire
(tertiary) air  ports in  the radiant section of  the boiler  above the rear of
the rotary  portion.   In  addition, an afterburning  grate was  located   at the
discharge of the rotary section.  Following field testing  in  1984,  the testing
engineers recommended that  combustion  air be eliminated from these locations
in the  system.   These modifications  were made,  but the air  supplies were
reinstated after Westinghouse purchased O'Connor.  Particulate,  metals,  and CO
emissions data  are available from  Gallatin, but  they are not included in this
analysis   because   the   facility   is   not   representative   of  new
Westinghouse/O'Connor technology.

      At Bay County  the  rotary portion of the  combustor  was designed  with a
tapered  end that protrudes  several  feet  into the  radiant section of  the
boiler.   The new Westinghouse/O'Connor  plants   are  designed with  a constant
diameter  barrel; the end of the barrel   is flush with  the  waterwalls   rather
than extending  into the radiant  section of the  boiler.    In  addition,  the
                                     3-19

-------
afterburning grate  is  a water cooled Detroit  Stoker  vibrating grate  rather
than a stationary design.

3.3.1       Emissions  Data  for  Existing Facilities

      Initial  continuous CO measurements  made at  Bay County  indicated average
emissions of 100-200 ppmv.   Westinghouse  concluded  that  these  relatively  high
CO levels were due to  (1)  a low temperature zone below  the  protruding  barrel
where mixing was not completed and (2) smoldering  of ash on the  afterburning
grate.22   Modifications were made to the combustion air distribution  system,
including the addition of  rows of tertiary air nozzles  in the  front and  rear
boiler walls above the rotary  combustor  (similar  to those originally in place
at Gallatin) and a small percentage of total air supplied beneath  the  after-
burning grate.   These  modifications  reduced  CO emissions to below 100 ppmv.
Results of continuous  CO monitoring data from Bay County are  reported to be  57
ppmv (3-hour average).  64 ppmv (7-hour  average),  and 83  ppmv (9-hour average)
during  three  separate testing  periods.23     Westinghouse  has  gathered
uncontrolled and stack  CDD/CDF data  at  Bay County, but the results have not
yet been reported.

      The available Bay County emissions data and  an assessment  of combustor
performance are  presented  in  Table  3-3.   The  good combustion practices for
rotary  waterwall  combustors  require  technology-specific application.   For
example, the requirement for four separately adjustable air plenums includes
the  3x2  arrangement of  windboxes  in the  rotary section of the  unit  and  a
source  of  combustion  air  under  the  afterburning  grate below the combustor
discharge.   In  addition,  the O'Connor  design typically operates  at lower
excess  air levels  (40-80  percent)   than  conventional  mass burners  (40-130
percent).  However, the  basic  approach to  combustion control of  emissions  is
the  same:   good  mixing is required  at  sufficient temperatures to destroy
organic emissions, and the potential  for  downstream formation  of  CDD/CDF  must
be minimized.

3.3.2       Model Plant Baseline  Emissions

      The Bay County.  FL CDD/CDF emission results have not yet  been reported;
thus,  no  measured  data are currently available  to support  baseline emission
estimates  from   Westinghouse/O'Connor  combustors.    Therefore,  baseline
uncontrolled CDD/CDF emissions of 300 ng/dscm  were established  for the  lll(b)

                                     3-20

-------
      TABLE 3-3.   MASS  BURN ROTARY  WATERWALL MWCS  -  PERFORMANCE ASSESSMENT
FACILITY
NUMBER OF UNITS - FGC
UNIT SIZE, tpd (Mg/day)

UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)

CONTROLLED EMISSIONS
CDD/COF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
GOOD COMBUSTION
PRACTICE RECOMMENDATIONS
                                Bay County. FL
                                2 - ESP
                                255 (232)
                                Not Available (NA)
                                60-80
                                NA
NA
60-80

FACILITY DESIGN
AND OPERATING CONDITIONS
Temperature at fully
mixed height

Underfire air
Overfire air capacity



Tertiary air design


Auxiliary fuel  capacity



Exit gas temperature

OPERATION
Excess air

Turndown

Tertiary air


Start-up procedures


Auxiliary fuel  use


VERIFICATION
02 levels

CO

temperature

Air distribution

Exit gas temperature
1800°F (982°C) average
4 plenums, including
one at burnout grate

Sum of secondary and
tertiary air designed to
supply 40% of total  air

Complete coverage and
penetration

That required to achieve
temperature limits
during start-up

<450°F (232°C)
3-9% 02 in flue gas (dry)

80-110% design load

Complete coverage and
penetration

Auxiliary fuel to
design temperature

High CO. low temp;
start-up/shutdown


Monitor

Monitor «100 ppmv at 7% 02)

Monitor

Monitor

Monitor

           3-21
1400°F (760°C) at inlet
to convective section

4 plenums (one at
afterburning grate)

Confidential
Confidential


Oil - 40% load



450°F (232°C)


5-57% 02 (wet)

30% minimum

Not achieved
Use steam preheat from
adjacent combustor

NA
Yes

Yes

Yes

UF. OF. tertiary

Yes

-------
model plant  based  on engineering judgement.   Based  on the results  reported
from  Bay  County,   baseline  CO emissions  were  established  at  100  ppmv.
Uncontrolled  PM emissions  are assumed  to  be  2  gr/dscf  (4600  mg/dscm).
consistent  with uncontrolled  PM  measurements  at  conventional  mass  burn
waterwall facilities.

3.4         Modular Excess  Air MWr.s

      The population of planned and projected modular excess air MWCs consists
of several distinctly  different designs.   The three design types  identified
with facilities in  planning,  permitting, or construction stages include:

      •     Vicon/Enercon  (7  known projects)
      •     Cadoux  (3)
      •     Basic (1)

All three of these  designs  utilize multiple combustion chambers; Vicon/Enercon
and Basic also employ flue  gas recirculation (FGR).  One key difference in the
physical designs is  that  the Basic  primary chamber is a membrane  waterwall,
while Vicon/Enercon  and  Cadoux use  refractory wall combustors with  separate
waste heat boilers.

3.4.1       Existing Facilities Emissions Data

3.4.1.1     Pittsfield. Massachusetts

      There are three  sets of CDD/CDF data available from  modular  excess air
MWCs.  The first data set  includes the parametric test results obtained from a
research program conducted at the Vicon/Enercon  facility  in Pittsfield. MA.6
A  facility equipment schematic is  shown in Figure 3-4.  The  plant comprises
three 120  tpd (109  Mg/day)  units  and  two waste  heat  boilers.  Testing was
performed  with two  of the  three  units in  operation, which  is  the normal
operating condition  for the facility.   Each boiler exhausts to an electrified
granular bed  (EGB)  filter  for removal  of PM.   The EGBs typically  operate at
475°F (246°C).  Organic emissions, including CDD/CDF,  PCBs,  chlorophenols.  and
cnlorobenzenes, were measured over a large range  of  operating  conditions and
while firing various fuels (MSW. PVC spiked MSW, PVC free waste).
                                     3-22

-------
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-------
      Table  3-4  presents  a  summary  of average  CDO/CDF  and CO  emissions
reported for  each  operating  condition investigated  in  the parametric test.
The temperature specified for each test condition  is measured at the exit of
the  secondary combustion  chamber.    Each  test condition  consisted  of  two
individual  sampling runs, with the  exception  of the 1400°F condition,  which
included only one  run.   Sampling for CDD/CDF was  performed at  the boiler
outlet for each  operating  condition.   CDD/CDF stack  sampling was performed
during two conditions (1800°F-MSW  and  1800°F-MSW + PVC). and  CDD/CDF  samples
were gathered at the  tertiary  duct  (just  upstream  of the  boiler) during the
eight other conditions.   Carbon monoxide emission levels were measured in the
tertiary duct  and  at the boiler  outlet  during all   runs.   Fairly extensive
process  monitoring  was  performed  during  this   test program,  including
measurement of airflows and temperatures at various locations in the system.
Testing  was  performed  for  the  suspected  precursors  of  CDD/CDF  (PCBs,
chlorobenzenes,  chlorophenols).   Continuous  monitors were maintained  to
measure Og,  CC"2,  CO.  SOg, NOX,  HC1.  and  THC at  various  locations  in  the
system.  Control of  combustion temperatures was maintained by modulation of
feed rates  and recirculated flue gas and. to a  lesser extent,  fresh airflows.

      One of the main conclusions made in the data analysis was that CDD/CDF
emission levels were not generally affected by  the different waste character-
istics evaluated  in the program.   However,  as  expected, emissions of  HC1 were
noticeably affected  by PVC  content  in the waste.   In most  cases.  CDD/CDF
concentrations increased at  each  sampling  location  as  the  flue gases passed
through the system.  The temperatures at the tertiary duct sampling  location
are  nearly  equivalent  to  the target  values  specified   in  each  sampling
condition.    The  sampling point was  upstream  of the  flue  gas recirculation
injection point (see Figure 3-4).   The amount  of recirculated  (tempering) air
injected into the  tertiary duct controls the  boiler  inlet gas temperature,
which varied from approximately 1100°F (593°C) during the 1300°F-MSW condition
to approximately 1400°F (760°C) during normal   operating conditions  (1800°F-
MSW).  The  average  boiler outlet gas temperature varied from 460 to 540°F (255
to  282°C).    Therefore,  the  flue gases  pass   through  the  critical  CDD/CDF
formation temperature (approximately 300°C) in the boiler.   This is reflected
by the  increases  in CDD/CDF concentrations between  the tertiary and boiler
outlet sampling locations.   This result was observed during six of the eight
conditions.   The formation  rate  appears  to  be higher than  actually may be
occurring,  because the gas  stream  at the boiler outlet location contains gases
recirculated  from  ahead of the APCD.   Increased  concentrations  of  COD were

                                     3-24

-------
TABLE 3-4.  PITTSFIELD,  MA MODULAR EXCESS AIR MWC
               EMISSIONS TEST DATA
TESTING CONDITION
1300°F - MSW
1400°F - MSW
1550°F - MSW
1550°F - MSW + H20
1800°F - MSW
1800°F - MSW. low 02
1800°F - MSW + PVC
1800°F - PVC free
1800°F - PVC free + PVC
1800°F - PVC free + H20
TERTIARY DUCT
CDD/CDF
(ng/dscm)
112
18
15
57
-
76
-
31
14
48
CO
(ppmv)
201
44
9
17
4
7
6
1
6
8
BOILER OUTLET
CDD/CDF
(ng/dscm)
403
40
57
21
94
165
148
71
87
28
CO
(ppmv)
148
22
15
14
12
9
7
9
13
7
STACK
CDD/CDF
(ng/dscm)
-
-
-
-
154
-
261
-
-
-
                      3-25

-------
measured between the two  sampling points during all  but two conditions  (1550°F-
MSW + H20.  and 1800°F-PVC free + H20).   The  influence  of water  on  the  CDD/CDF
formation mechanism must  be investigated further  in  order  to draw  conclusions
related  to  this observation  at  Pittsfield.   No PM  sampling  was performed
during any  of the test  runs.   However, waste moisture content may have  reduced
the  amount   of  PM  that  was  entrained  in  the  fly  ash  and   available for
downstream  catalytic reactions to  occur.   A normal  sootblowing cycle was
reportedly  performed  for the boiler during each 4-hour  sampling run.   The
facility was reportedly scheduled for an annual maintenance shutdown  2  weeks
after the completion  of  testing;  the condition  of  the  plant  was considered
normal  during  testing  (no  special  maintenance   was  performed prior  to
initiating  the program).

      Paired runs  gathered during  normal operating  conditions (1800°F-MSW)
provided an average CDD/CDF emission rate of  94 ng/dscm at the boiler outlet
(154  ng/dscm at the  stack).   At the  1500°F-MSW  test condition,  the  total
CDD/CDF emissions averaged  57  ng/dscm at the boiler  outlet (no  stack measure-
ments available).  As secondary chamber temperatures  were decreased to  1300°F.
the  average CDD/CDF emission  rate  increased  to 403  ng/dscm  at  the boiler
outlet.   The low temperature runs were performed for  experimental  purposes and
are not expected to be  encountered during normal operating  conditions.

      Stack  testing  was  performed  at  Pittsfield  during   two  operating
conditions  (1800°F-MSW  and 1800°F-MSW  + PVC).  Concentrations  of  CDD/CDF
increased by 64 and 76 percent,  respectively,  from the boiler outlet location
to the stack.  Average  boiler  outlet gas temperatures ranged from 472 to  536°F
(250 to 280°C)  during these four sampling runs.

      During all the aforementioned  testing  runs, CO emissions  were measured,
and  average  emission levels at the  boiler  outlet did not exceed  22 ppmv (4-
hour average) except when operating at 1300°F,  when 148 ppmv was measured.

      The  extensive  emissions  and  process  data  generated  at  Pittsfield
demonstrate that sufficiently  high temperatures and adequate mixing conditions
are  present  to  minimize  CDD/CDF  and  CO  emissions  at normal  operating
conditions.  The  low emission levels measured  at Pittsfield confirm that the
units have good combustion  practices in  place.
                                     3-26

-------
3.4.1.2     Piaeon Point.  Delaware

      A second data  set available for the  Vicon/Enercon facility  is  Pigeon
Point. DE.  This  plant  comprises five 120 tpd  (109 Mg/day)  units  that  fire a
mixture of  MSW  and RDF, with  ESP  controls.   The  compliance test  at  Pigeon
Point was conducted in two phases.   Phase I  consisted of HC1. $03, CO.  and PM
measurements made in  the stack.   Particulate testing was also performed at the
ESP inlet location for  all four  units.   Phase  II  involved  stack  sampling for
CDD/CDF and heavy metals (Pb. Hg. Be. Ni, As. Cd. Cr).

      The three-run average uncontrolled  PM  levels  for  each  of  the four flues
tested were  1.03 gr/dscf (2370  mg/dscm), 1.03 gr/dscf (2370 mg/dscm).  0.90
gr/dscf (2070 mg/dscm),  and  0.43 gr/dscf (990  mg/dscm).24   One of  the flues
discharges gases from two combustors.   Average  flue gas temperatures entering
the ESP ranged from 393 to 433°F (200 to 223°C).   Due to the low particulate
concentrations   and  the  low operating  temperature,   it  is  doubtful  that
substantial  CDD/CDF formation would occur in the ESP.

      Three CDD/CDF sampling  runs were performed in the stack of unit #2.  The
average  emissions were  reported to  be  105 ng/dscm.24   The  average  stack
temperature was  reported to  be  374°F (190°C).   The CO  data  included in this
test were measured by  ORSAT  analysis  and were  reported to  be 0.0  percent  by
volume.  The CDD/CDF concentrations in the  ESP fly ash  are  also  reported for
each  sampling run.    Very limited  process data  are  available  to use  in
characterizing the operation  of  the Pigeon Point facility during testing.  The
plant  attempts to feed a mixture  of  5  pounds  RDF per  pound of MSW.  and  it
appears  that this  ratio was  maintained during  the  tests.   Based on  the
assumption  that  the  combustor  design  and  operation are  similar  to that  at
Pittsfield.  it can be concluded  that good combustion practices are in place at
Pigeon Point.  The measured emission levels from  Pigeon  Point  and Pittsfield
confirm the good performance of the Vicon/Enercon  design.   The  consistency  of
the CDD/CDF data with  that measured at Pittsfield  also  indicate  that CDD/CDF
emission levels  are more dependent on combustion technology than on waste feed
characteristics.

3.4.1.3     Alexandria. Minnesota

      A third data set  is  available from a  facility  using  the  Cadoux design.
Emissions testing was  performed  at the  Pope/Douglas  Waste-to-Energy Facility

                                     3-27

-------
in Alexandria.  MN.  in  July  1987.  This plant began operating in May 1987 using
two 38 tpd (35 Mg/day) Cadoux modular excess air combustors.   Both  units  are
equipped with an  ESP.   Average CDD/CDF emissions at the stack were reported to
be 446 ng/dscm.25   The  continuous monitoring results indicated that average CO
emissions were 24 ppmv (1-hour  average).   The average flue gas temperature at
the ESP  inlet sampling  location  ranged  from  490 to  503°F  (254 to  262°C).
These values are in the  temperature window where CDD/CDF formation  has been
observed.  Therefore,  it is  assumed that  CDD/CDF at the  ESP  inlet  was  lower
than the concentrations  in the  stack.   The CDD/CDF and CO  measurements were
made on Unit  #2.   Particulate sampling was also performed in the stack of both
units.

      Thermocouples were  installed  in Unit #1  at  two locations in the primary
combustion chamber.   The  first  was located on  the side wall  at  the  grate
level, and the second  was in  the top of the chamber.   The  average temperature
at the grate varied from  1300 to 1650°F (704 to 899°C) and the temperature in
the upper furnace  ranged from  1770  to 1990°F  (965  to 1088°C).   Charge rates
were measured during the  testing program and both units were operating between
100 and  145  percent rated  capacity.  Oxygen levels were  also measured  in  an
eight-point traverse at the combustor outlet,  and average  concentrations were
14.8 percent at Unit #1 and  12.8 percent  at Unit #2.   These  values  equate to
approximately 245 percent and 160 percent  excess air. respectively.

3.4.2       Model  Plant Baseline  Emissions

      Baseline  emissions  for  the  model  plant  are  based  largely  on  the
performance of the  two Vicon/Enercon MWCs  at Pittsfield and Pigeon Point.   The
emissions  data  from these systems  and the  Cadoux facility  at  Pope/Douglas
County are plotted  together  in  Figure 3-5.   The only  data  included from  the
Pittsfield  parametric test  are those  runs which took  place under  normal
operation, firing 100  percent MSW.   The off  spec, low temperature runs are not
expected  to  be  encountered  in  normal  operation.    Baseline emissions  are
assumed to be 200  ng/dscm  CDD/CDF and 50  ppmv  CO.   Uncontrolled  PM emissions
are assumed to be 2 gr/dscf (4600 mg/dscm), which is an average value for mass
burn systems.
                                     3-28

-------
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                                    3-29

-------
3.5         Mass Burn  Modular  Starved Air MWCs

      There are at least four manufacturers of starved air modular MWCs with
units  in  planning,  permitting, and/or  construction  stages (Consumat.  Clean
Air. Joy.  and  John  Zink).   Although modular starved air facilities  comprise
the largest  category  of existing MWCs  in  total  facility numbers, there  are
very few identified in the planned and  projected  population.  This may  be  due
to  the  short amount of  time  required  to  construct  a  modular facility;  the
current  list of  planned and  projected plants  may  represent  shorter term
projections for this population.

      Generic descriptions of modular starved air MWCs are included  in  EPA's
MWC Report to Congress.   Refinements in  combustor design and controls  continue
to  be  made  in  the  new  starved  air MWC  population.   Consumat  Systems  has
increased the volume of the secondary  combustion  chamber  in their  more  recent
designs.26   This modification  is  intended  to increase  residence  time  of gases
for better mixing.    A  second change  in  the Consumat design  is  related  to
control of the  charging  rate.   Originally, the charging  rate was based on  a
pre-established interval  which  was  adjusted manually.   The loader operator  was
given a signal  every  5-10  minutes  to  add  another charge  to the loader.   The
size of the  charge  (heavy,  normal,  or  light) was also indicated by  a  signal
which was based on the primary  chamber  temperature.  The operator adjusted  the
size of  individual  charges based on the  signal,  increasing  the size  if  the
temperature was below the  setpoint and  decreasing the charge if the  setpoint
temperature  was  exceeded.   In the newer  Consumat designs,  the time between
charges  is  automatically  adjusted based on  a feedback  signal  from  the
temperature controller.   The operator does  not have to adjust the size of each
charge manually: instead the controller  will  automatically lengthen or shorten
the time between  charges,  eliminating  dependency  on operator judgment.  This
feature may contribute to lower organic emissions, because  it  is hypothesized
that CDD/CDF  levels correlate  with the number of CO spikes.   The adjustable
feed control  sequence may provide less frequent  spikes  in CO  emissions  and
lower uncontrolled trace organic  emissions.

      The Joy design is similar to Consumat in that  transfer  rams  are used to
move waste through  the  primary combustion chamber.   Some unique  features in
the Joy system are an  underflre air and steam  injection system for temperature
control, and a modulating  temperature  controller which  automatically adjusts

                                     3-30

-------
the induced  draft  (ID) fan damper.   The air/steam  injection  system in the
primary chamber is designed to  reduce  high  localized hearth temperatures to
minimize clinker formation and minimize vaporization of  inorganics  (metals).
In addition,  alternating the  exposure of  the  waste  to underfire  air  and  steam
reportedly maximizes the conversion of fixed  carbon  content of the waste to
C0£.   The  automatic  control  of the  ID  fan  damper results  in  fewer furnace
upsets  due  to pressure  imbalances,  changes  in  draft,  or  changes  in  total
combustion gas flow.   When these upsets occur  and temperatures increase,  a
thermocouple  in  the dumpstack  senses  the increase  in  temperature  and the
controller drives  the  ID fan damper to  a  more  open position,  resulting in
improved system stability.   If the thermocouple senses an immediate decrease
in temperature the ID  fan  damper  is driven  to a more closed position,  which
reduces air flows and boosts operating temperatures.

3.5.1        Existing  Facilities Emissions Data

      CDD/CDF emissions data are  available  from several  modular starved air
MWCs.   The most recent  data has  been gathered  by Environment Canada at Prince
Edward Island (PEI)  and by  New York DEC at the Oswego, Oneida, and  Cattaraugus
County MWCs.    Uncontrolled data  are  available from  PEI,  Cattaraugus County.
and Oswego.   The available  emissions data are included in  Table  3-5  along  with
a comparison  of individual  plant performance relative to the good combustion
practice recommendations  for modular starved  air MWCs.

3.5.1.1     Prince  Edward Island

      Emissions testing  was  performed  at PEI at  four operating  conditions
(normal,  long  feed  cycle,  high  secondary  chamber temperature,  and  low
secondary chamber  temperature).   The facility consists of three Consumat CS-
1600 combustors,  each  rated at 36  tpd (33 Mg/day).  The combustors exhaust to
a  common  waste heat  recovery  boiler  and  then  to a stack  without further
emissions control.   A process  schematic of the facility is provided  in Figure
3-6.   Sampling was performed at  the  boiler  inlet location and  in the stack.
The primary  operating  variables were  primary  and  secondary  combustion
temperatures and feed  cycle.   Three sampling runs  were  performed  for  each
condition.   The average  CDD/CDF  and  CO data  are presented  in  Table 3-6 for
each operating  condition.&
                                     3-31

-------
         TABLE  3-5.  MODULAR STARVED AIR  MWCS - PERFORMANCE ASSESSMENT
                                    PAGE  1  OF 2
FACILITY
NUMBER OF UNITS -  FGC
UNIT SIZE, tpd (Mg/day)

UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)

CONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
                               Prince Edward Island
                               3 -  None
                               36 (33)
                               409
                               62
                               225
GOOD COMBUSTION
PRACTICE RECOMMENDATIONS
FACILITY DESIGN
AND OPERATING
CONDITIONS
Temperature at fully
mixed height

Secondary air capacity
(not an operating
requirement)

Secondary air injector
design

Auxiliary fuel capacity
Exit gas temperature


OPERATION
Excess air

Turndown

Secondary air

Start-up procedures


Auxiliary fuel  use


VERIFICATION
02  levels

 CO

 Temperature


 Air distribution

 Exit gas  temperature
1800°F (982°C) average
80% total  air
As required to achieve
temperature limits
during start-up

<450°F (232°C) at PM
control device inlet
6-12% 02 (dry)

80-110% design load

80% total air

On auxiliary fuel to
design temperature

High CO. low temp;
start-up/shutdown


Monitor

Monitor  (<50 ppm at 7% 02)

Monitor


Monitor

Monitor
1832°F (1000°C)
(secondary chamber)

NA
That required for penetration  NA
and coverage
NA



363°F (184°C)



12% 02

NA

NA

NA


NA



No

No

Primary  and
secondary  chamber

No

No
                                         3-32

-------
          TABLE 3-5.   MODULAR STARVED  AIR MWCS  -  PERFORMANCE ASSESSMENT
                                      PAGE 2 OF  2
FACILITY
NUMBER OF UNITS - FGC
UNIT SIZE, tpd (Mg/day)

UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)

CONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
Cattaraugus County,  NY
3 - None
38 (35)
345
NA
Onelda County, NY
4 - ESP
50 (45)
FACILITY DESIGN
AND OPERATING CONDITIONS
                                462
FACILITY DESIGN
AND OPERATING CONDITIONS
DESIGN
Temperature at fully
mixed height

Secondary air capacity
(not an operating
requirement)

Secondary air injector
design

Auxiliary fuel capacity

Exit gas temperature


OPERATION
Excess air

Turndown

Secondary air

Start-up procedures


Auxiliary fuel use
1800-2000°F  (983-1093°C)
(secondary exit)

At least 40% total  air
NA


Gas - 30% load

502°F (216°C)  (stack)



NA

NA

40% of total air

On gas to 1800°F (983°C)
in secondary

Start-up
1800°F (983°C)
(secondary exit)

NA
NA
Gas - 100% (not used)

400-450°F (204-232°C)
(boiler outlet)
NA

NA

NA

Not used


None
VERIFICATION
02 levels

CO

Temperature


Air distribution

Exit gas temperature
No

No

Primary and secondary
chamber

Primary air

Yes
No

No

Primary and secondary
chamber

No

Yes
                                         3-33

-------
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3-34

-------
TABLE 3-6.  PERFORMANCE TEST DATA
     PRINCE  EDWARD  ISLAND MWC

CONDITION
Normal
Long Cycle
High Secondary
Low Secondary
BOILER INLET
CDD/CDF
(ng/dscm)
NA
0
1
42
TEMPERATURE
op oC
1544 840
1544 840
1922 1050
1364 740
STACK
CDD/CDF
(ng/dscm)
409
441
198
424
CO
(ppmv)
62
39
38
53
TEMPERATURE
op oC
363 184
363 184
361 183
266 130
               3-35

-------
      The data in  Table  3-6  indicate that COD/CDF emission levels in the stack
are partially due to formation that occurs in the lower  temperature  portions
of  the  system.    With  the  exception  of  the  low  secondary temperature
conditions. CDD/CDF emissions are near zero at the boiler inlet.   The  higher
emission levels during the  low secondary temperature condition  likely  result
from  insufficient  temperatures to  provide  destruction   of  CDD/CDF  and
precursors.   Secondly,  the  operating variable that  had  the most  noticeable
effect on CDD/CDF stack emissions was  the high  secondary  chamber temperature.
These data provide support for the combustion temperature requirements  in  the
MWC recommendations.

3.5.1.2     Cattaraugus  County. New York

      The second set of CDD/CDF  emissions data was gathered  at  the Clear  Air
facility in Cuba  (Cattaraugus  County), NY.  The plant consists of three  38  tpd
(35 Mg/day) units that began  operating in 1983.  The plant  has  heat  recovery
but uses no flue  gas  cleaning  device.  Two CDD/CDF sampling runs are available
from testing performed by New York State in  1984, and  average  emissions were
reported to be 345 ng/dscm.27  There  are no  CO data available  with  the test
results.   Primary chamber temperatures were  approximately 2200-2300°F  (1204-
1260°C)  and  secondary  chamber  temperatures  were  maintained  near 2000°F
(1093°C)  during testing.

3.5.1.3     Oneida County. New York

      Oneida County is another Clear Air facility which  comprises  four  units
at  50  tpd (45 Mg/day)  each.   The plant  has heat recovery  in place and  is
equipped with an  ESP.   Stack testing  was performed  by New York  State  DEC  in
1985.    Average  CDD/CDF  emissions  at  Unit #1  were 462   ng/dscm.15    The
temperature at the ESP inlet was  458°F  (237°C).  Primary chamber temperatures
were approximately 1600-1800°F (871-982°C) and secondary chamber temperatures
were 1700-2000°F  (927-1093°C) during testing.

3.5.1.4     Additional  Data

      Uncontrolled PM emissions  data are available from  Tuscaloosa.  AL [0.07
gr/dscf  (160 mg/dscm)]^,  PEI [0.098 gr/dscf  (225 mg/dscm)]*. and Windham. CT
[0.07  gr/dscf  (160  mg/dscm)].28   CO  emissions  are available from  PEI  (38-62
ppmv)5 and from Red Wing,  MN (2 pprnv).™

                                     3-36

-------
      The  available emissions  data  provide  evidence  that  relatively  low
CDD/CDF concentrations can be achieved by modular starved  air  MWCs.   The key
conditions that  lead to low  emissions  are the  same  as specified for  other
technologies:  achieve  good  mixing at adequate temperature and minimize the
conditions that lead to  downstream  formation of CDD/CDF.   Starved air  MWCs can
achieve adequate secondary  chamber  temperatures by control  of  air  flows.   The
fully mixed location in a modular  starved air  MWC can be defined  at  the  exit
of the secondary  combustion  chamber.   The available data  also  indicate  that
total elimination of downstream formation  of CDD/CDF  may not be feasible.
However,  systems  should be designed and operated in a manner  which minimizes
the potential  for these  occurrences.

3.5.2       Model  Plant  Baseline Emissions

      Figure 3-7  presents  the available  CDD/CDF emissions data in graphical
form.  Based  on  the available emissions  data  and  on judgements  that  design
improvements made  to new  systems   (as discussed  above)  will  result  in  lower
emission  levels,  baseline uncontrolled CDD/CDF emissions were  established at
300 ng/dscm.   Based on available  data  from several existing facilities,  newer
facilities are also  expected  to  be able to achieve uncontrolled  particulate
matter emissions  of 0.1  gr/dscf (230 mg/dscm) and CO emissions  of 50 ppmv.

3.6         Model  Plant  Performance Estimates - RDF Combustors

      Refuse-derived-fuel  (RDF)  combustion  technology  includes  the use  of
conventional  RDF  spreader stokers,  fluidized bed combustors (FBC).  and RDF co-
firing in coal fired boilers.  The RDF model plants in  this analysis include
two spreader stokers and two  FBC facilities.  One of the spreader stoker model
plants burns  100  percent  RDF and one burns  a  50/50  mixture  of RDF  and  wood
waste.  Based  on  projections  of  the  new population  of  FBCs.  one  circulating
fluidized bed  (CFB)  model  plant  and  one  bubbling fluidized  bed  model  plant
were  developed.   Both of the  fluidized  bed models  are  assumed to  burn  100
percent RDF.

3.6.1       RDF Spreader Stokers

      The  population of planned   and projected RDF  fired spreader  stoker
boilers is anticipated  to  include  two major manufacturers--Babcock  &  Wilcox

                                     3-37

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(B&W)  and  Combustion  Engineering  (CE).   Both of  these  manufacturers  have
developed new RDF combustors  with unique design features.

      Figure 3-8  shows  the configuration of the  new  B&W  design.   The lower
portion of the boiler is pinched to provide arches in  the  front and rear wall
and a row of  overfire  air  nozzles  is located at each arch.  Overfire  air  is
also injected below  the  arches.   The configuration is designed  to provide a
well mixed region in the lower furnace above the  traveling  grate.   The first
facility to use this design is the Maine Energy Recovery Company (MERC) plant
at Biddeford, ME.  Another design  feature which  is  characteristic  of  new RDF
fired MWCs  is a metered feeding  system.   A  Detroit  Stoker metered  feeding
system (shown in Figure 3-9)  is also  used at MERC.  The metered feeding system
consists of two RDF  hoppers,  a  ram  feeder, and a variable speed conveyor which
transports RDF to air swept distributors at a constant rate, thus providing a
consistent fuel feed rate  and uniform distribution  of waste on  the traveling
grate.

      A second new RDF boiler design  being  supplied  by Combustion Engineering
includes multiple, separately  controllable  underfire  air  plenums  (Figure  3-
10).  This design provides  the  operator with the ability to vary underfire air
distribution to each  region of  the  waste bed based on the distribution  of fuel
on  the  grate.   A second  unique  design  feature in  the  CE boilers   is the
overfire air system.   There  are  tangential  overfire air jets  located  in the
furnace  corners,  each  of  which  includes  three  levels  of  separately
controllable nozzle  banks.   There are also  three rows  of overfire air  nozzles
on  the  furnace walls  (one row  on  the front  wall  and two  rows on the  rear
wall).   Although  the wall  fired  air  is normally operated when  burning coal.
the tangential  and wall  overfire air  systems can be fired simultaneously.

      Metered feeding and segmented  underfire air supplies  are  both designed
to accomplish the same objective:  to provide  uniform stoichiometries  in the
grate/fuel bed  region  of the furnace.  This  is a necessary requirement for
achieving  good  combustion.   The  objective can  be accomplished  either  by
biasing the  supply of  combustion  air to the  portion  of the grate where the
waste is concentrated,  or by distributing the waste evenly  on  the  grate with
underfire air delivered  from  a single plenum.
                                     3-39

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                               Overfire Air

                       Undergrate Air
Figure 3-8.   MERC - B&W Boiler Design
                 3-40

-------
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3-41

-------
RDF
Distributors
                                                                               Tangential
                                                                               Overflre Air
Crate Surface
Drive Shaft
Undergrate
Air Compartment
                                                                              Sifting Screw
                                                                              Conveyor
                   Figure 3-10.   Mid-Connecticut CE  RDF Fired  MWC
                                          3-42

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3.6.2       Existing Facilities  Emissions  Data

      A summary of emissions  test  data  is  presented  in Table 3-7 for RDF fired
facilities that are judged to be  representative  of  the  planned and projected
population.

3.6.2.1     Biddeford.  Maine

      The Biddeford. ME. MWC was  tested for  CDD/CDF by  EPA in December 1987.
The  plant  comprises two  boilers, each  rated  at 350  tpd (318  Mg/day)  RDF.
Emissions control  on each unit is  achieved by a cyclone,  a spray dryer, and a
baghouse.  Emissions were measured at the  spray dryer inlet (downstream of the
cyclone) in conjunction with compliance testing  performed  in  the  stack.   The
unit that was tested was operating at full load during  the test.  Although an
RDF/wood mixture is fired during normal operating conditions.  100 percent RDF
was  burned during  the  test.   Three CDD/CDF  sampling runs  were performed and
average  unabated  emissions were 903 ng/dscm.29   Inlet  particulate emissions
were 3.56 gr/dscf (8190 mg/dscm).  and average CO  emissions were 81 ppmv.   The
boiler was operated at approximately 65-70 percent excess air  during the  test
with  an overfi re/underfi re  ratio  of  56/44.    Each test run  was 4  hours'
duration.  The average temperature at the  spray dryer inlet location was 374°F
(190°C).

3.6.2.2     Red Wind.  Minnesota

      The  Red  Wing facility  comprises two  35-year-old coal-fired  spreader
stoker  boilers  that have been  retrofitted  to burn 100 percent  RDF.30   The
boilers  were enlarged  by extending  the furnace  down  into  the  basement.
removing the coal  bottom ash hoppers,  lowering the  stokers,  and adding a 14-
foot  (4.3  m)  waterwall  extension  fabricated from membrane panels with  high
nickel  alloy  weld overlay.   The  existing  tube   and tile upper  furnace  was
connected to  the new membrane walls by  installation  of a transition header.  A
new multilevel,  multipoint, heated overfire air system was  installed to ensure
good mixing.

      The facility was  tested for  CDD/CDF  in  1987.   Emissions at the ESP inlet
were  reported to be 60 ng/dscm and average stack  emissions were 28 ng/dscm.31
Inlet  particulate  emissions were  reported to be  2.13 gr/dscf  (4900  mg/dscm)

                                     3-43

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        TABLE 3-7.   RDF FIRED  SPREADER  STOKERS  -  PERFORMANCE ASSESSMENT
                                     PAGE  1  of 2
FACILITY
NUMBER OF UNITS - FGC
UNIT SIZE, tpd (Mg/day)

UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)

CONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
GOOD COMBUSTION
PRACTICE RECOMMENDATIONS
                                Red Wing,  MN
                                2 - ESP
                                360 (318)
                                NA
                                127
                                4900
28
99

FACILITY DESIGN
AND OPERATING CONDITIONS
DESIGN
Temperature at fully
mixed height
Underfire air control
Overfire air capacity

Overfire air injector
design

Auxiliary fuel capacity
Exit gas temperature


OPERATION
Excess air

Turndown

Overfire air


Start-up procedures

Auxiliary fuel use


VERIFICATION
02 levels

CO

Temperature

Air distribution

Exit  gas  temperature
1800°F  (982°C) mean



As required for uniform
bed stoichiometry

40% total air

Penetration and coverage
As required to achieve
temperature limits
during start-up

<450°F (232°C)  at  PM
control device inlet
3-9% 02 (dry)

80-110* of design

Coverage and
penetration

Auxiliary fuel

High CO. low temp;
start-up/shutdown


Monitor

Monitor (100 ppm at 7% 02)

Monitor

Monitor

Monitor
>1800°F (982°C)  inlet
to first convective
section

2 plenums
50* total air




100% load



260-450°F (127-232°C)



7-11% 02

40% minimum

50% at full load
20% at minimum load

Gas

Start-up



Yes

Yes

Yes

Yes

Yes
                                         3-44

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        TABLE 3-7.   RDF FIRED SPREADER STOKERS  -  PERFORMANCE ASSESSMENT
                                     PAGE 2 of 2
FACILITY
NUMBER OF UNITS - FGC
UNIT SIZE, tpd (Mg/day)
UNCONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
PM (mg/dscm)
CONTROLLED EMISSIONS
CDD/CDF (ng/dscm)
CO (ppmv)
COMBUSTION PARAMETERS
Biddeford. ME
2 -
300 (272)
903
81
8190
FACILITY DESIGN
AND OPERATING CONDITIONS
DESIGN
Temperature at fully
mixed height
Underfire air control
Overfire air capacity
Overfire air injector
design
Auxiliary fuel capacity
Exit gas temperature

OPERATION
Excess air
Turndown
Overfire air
Start-up procedures
Auxiliary fuel use
VERIFICATION
02 levels
CO
Temperature
Air distribution
Exit gas temperature
Not Available (NA)

Metered fuel  feeding
60% total  air
Gas - 40% load
374°F (190°C) at PM control
device inlet
7% 02
40% minimum (on gas)
60% total  air
Gas to 1800°F (982°C)
Routinely co-fire,  start-up,  shutdown

Yes
No
Not currently measured
NA
Yes
                                         3-45

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and average CO levels were  127  ppmv  (5-hour  average).  The Red Wing units are
designed to operate at 65 percent excess air with a 50/50 overfire/underfire
air  ratio.    The  average  excess  air  level  was  62  percent  during  CDD/CDF
testing, and  the  air distribution  was not specified.   The  design ESP  inlet
temperature  is 420°F  (216°C)  and   the  average  operating  value  was 425°F
(218°C).

      After the data  were subjected  to an  EPA QA/QC  review, the  inlet CDD/CDF
data were invalidated.   Therefore,  only the data measured  in the stack were
included in this analysis.

3.6.3       Model  Plant Baseline Emissions

      Based on the measured data from  Biddeford, the baseline  CDD/CDF  emission
levels for new RDF units have been  established  at 1000 ng/dscm.  Baseline CO
values of 100  ppmv are established  for  the  model  plants.   This CO emissions
level is expected to  be achievable  by  new  RDF fired units in  a short term (4-
hour) test.   Average uncontrolled   PM emissions  of  4  gr/dscf (9200 mg/dscm)
were assumed for the  model  plants based on  the Biddeford  data.

3.7         RDF/Wood  Co-Fired MWCs

      At this time there are no data  available to establish  baseline CDD/CDF
emissions  for RDF boilers  that fire mixtures of  RDF  and  wood.   Although
untreated wood will  probably have lower chlorine contents than RDF, the ring
structure  organics  emitted  from   the  combustion  of  wood   could  possibly
contribute  to CDD/CDF formation.   Due to  the absence of data to  indicate
otherwise, the same baseline  emission  levels are  assumed for  spreader stokers
firing mixtures  of wood  and  RDF:    1000 ng/dscm  CDD/CDF. 100 ppmv CO,  and 4
gr/dscf (9200 mg/dscm) PM.

3.8         Fluidized Bed Combustors

      There  are two  FBC model plants;  one bubbling  bed  facility  and one
circulating  fluidized bed  (CFB)   plant.    The  actual  growth  rate  of CFB
combustion   units  in  the U.S.  is  questionable at  this  time.   Several
communities  reportedly  have plans  for new CFB  units,  but  very  few are  in
construction or permitting  stages.32
                                     3-46

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3.8.1       Existing  Facilities  Emissions Data

      The two fluidized  bed  MWCs  in the U.S. (Duluth. MN and Lacrosse,  WI)  are
both  bubbling  bed  designs.    Each  plant  has  been  tested  for CDD/CDF.
Discussion of test  results is provided below.

3.8.1.1     Duluth. Minnesota

      The Duluth  facility normally combusts a mixture of RDF and sewage sludge
[120 tpd (109 Mg/day) fluff  RDF  and  345  tpd (314  Mg/day)  sludge at  18  percent
solids].   Emissions  are  controlled  by a  venturi  scrubber.    Testing was
performed at full operating load.  Total tetra-octa  CDD/CDF were measured  in
the stack downstream of the control  device.   The average  emission  levels  of
CDD/CDF  over  three  runs were  approximately 7.7  ng/dscm at 7 percent 02-33
Sixty-two 15-minute averages of  the CO emissions from the Duluth FBC indicated
levels between 1 and 31 ppm.   Controlled  particulate emissions levels were
0.0048 gr/dscf (11  mg/dscm).

3.8.1.2     LaCrosse. Wisconsin

      Diagnostic  and  compliance  tests were conducted at the Northern  States
Power French Island Facility Unit #1 at Lacrosse.  WI in May 1988.  All  testing
was conducted at  the  stack,  downstream of the electrified granular bed  filter.
The unit combusts a mixture  of fluff RDF [185 tpd (168 Mg/day)]  and  wood chips
[175 tpd (159 Mg/day)].  The average CDD/CDF emissions level observed in three
runs was  14.3  ng/dscm.34    CO emissions  at NSP averaged  275  ppm over  three
runs.   The  total  particulate  concentration  at  the stack  averaged   0.0184
gr/dscf  (42  mg/dscm) over   three  runs.   The gravel  bed scrubber  reportedly
operates at 325°F (163°C).

3.8.1.3     Sundsvall . Sweden

      Stack emissions test  data  are  reported by Gotaverken  for  a CFB facility
in  Sundsvall.  Sweden co-firing  peat.  wood, and  tires  with  RDF.35   Weight
percentages of each of the  fuels are not specified  in the  test  reports.  The
average  reported CDD/CDF  concentration was  392  ng/Nm3.    Carbon monoxide
emission  data   from Sundsvall  indicate that   the  units  can  maintain
concentrations below  100 ppmv.

                                     3-47

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3.8.2       Model  Plant Baseline Emissions

      The data  from  the Duluth and  the  LaCrosse FBCs are  used to establish
baseline CDD/CDF emissions for the bubbling  bed model  plant  (20  ng/dscm).  The
emissions data  from  Sundsvall  are used to  estimate  baseline emission for the
CFB models (400 ng/dscm).   Both models were  assumed  to have  CO emissions of  50
ppm.  Uncontrolled PM  emissions  are  assumed to  be equivalent to PM emissions
from RDF spreader stokers  [4 gr/dscf  (9200 mg/dscm)].
                                      3-48

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4.0         REFERENCES


1.    Radian  Corporation.     "Municipal  Waste  Combustors  -  Background
      Information for Proposed Standards:   lll(b)  Model  Plant  Description  and
      Cost of Control."   EPA-450/3-89-27c.  August 1989.

2.    Assessment of Municipal  Waste  Combustor  Emissions Under the Clean  Air
      Act. U.S.  EPA Advance Notice of Proposed Rulemaking. 52 FR 25399. July
      7.  1987.

3.    "Municipal  Waste Combustion Study:  Report to Congress."  EPA/530-SW-87-
      021a.   May 1987.

4.    "Municipal  Waste Combustion Study:  Combustion  Control  of MSW  Combustors
      to  Minimize Emission of  Trace Organics."  EPA/530-SW-87-021c.  May  1987.

5.    Environment  Canada.    NITEP.    "Two  Stage  Combustion."   EPS  3/UP/l.
      September  1986.

6.    New York State Energy Research and Development Authority.  "Results of
      the Combustion and Emissions Research Project  at  the Vicon Incinerator
      Facility  in Pittsfield.  MA."  June 1987.

7.    Radian Corporation.  "Municipal  Waste Combustion  Multipollutant  Study  -
      Summary Report."   North  Andover  RESCO,  North  Andover,  MA.  EMB Report
      No. 86-MIN-02A.  March 1988.

8.    Entropy  Environmentalists.    "Stationary  Source  Sampling  Report  -
      Pinellas  County  Resource  Recovery  Facility."   St.  Petersburg,  FL.
      February  and March 1987.

9.    Stieglitz, Vogg.   "New  Aspects of PCDD/PCDF  Formation in Incinerator
      Processes."    Presented at   NITEP   Conference  on  Municipal  Waste
      Incineration.  Montreal,  Quebec.  October 1-2, 1987.

10.   Hagenmaier.   et   al .    "Catalytic  Effects  of   Fly  Ash  from  Waste
      Incineration   Facilities  on  the  Formation  and   Decomposition  of
      Polychlorinated Dibenzo-p-dioxins  and Polychlorinated  Dibenzofurans."
      Environmental  Science  and Technology.  November 11. 1987, Vol. 21. 1080-
      1084.

11.   New York  State Energy  Research and Development  Authority.   "Results from
      the Analysis of MSW Incinerator Testing  at  Peekskill. NY."  DCN:88-233-
      012-21.  August  1988.

12.   Radian Corporation,  "lll(b) MWC  Profile Memorandum."   Submitted to  EPA
      September  9.  1988.

13.   Entropy Environmentalists.   "Emissions  Test  Report,  Municipal  Waste
      Combustion Study,   Wheelabrator Millbury.  Inc."   Prepared for the U.S.
      Environmental  Protection  Agency, Research Triangle Park,  North Carolina.
      EPA/EMB  Report No. 88-MIN-07. July 1988.

14.   "Municipal  Waste Combustion Study:  Emissions Data Base."   EPA/530-SW-87-
      021b.   May 1987.
                                     4-1

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15.   Radian Corporation.   "Emission  Test  Report - Marion County Solid Waste-
      to-Energy  Facility."   Brooks.  Oregon.   EMB  Report  No.  86-MIN-03.
      September 1987.

16.   "Emissions Test Results for  the  PCDD/PCOF  Internal  Standards Recovery
      Study Field Test;  Runs  1.  2, 3, 4.  5.  13.  and 14."   Memorandum from
      Michael  A. Vancil.  Radian  Corporation,  to  C.E. Riley.  EPA.   July 24.
      1987.

17.   Ogden  Martin.    "Environmental  Test  Report  -  Alexandria/Arlington
      Resource Recovery  Facility Units 1,  2. and 3."   March  9.  1988.

18.   Wheless. E.   "Air Emission  Testing  at  the  Commerce  Refuse  to  Energy
      Facility."    Presented  at  NITEP  Conference  on   Municipal   Waste
      Incineration. Montreal.  Quebec.  October 1-2,  1987.

19.   Linz. D., Gas  Research  Institute; Fleming. D..  Khinkis. M.. Abbasi, H.,
      Institute of Gas  Technology:  Penterson,  C.,  Riley Stoker Corporation.
      "Emissions Reduction  From  MSW Combustion Systems  Using Natural  Gas."
      Paper  presented  at  International  Conference  on   Municipal   Waste
      Combustion. Hollywood. FL, April 11-14.  1989.

20.   Rasmussen. M.   "Emission  Test at  a Danish  Energy From Waste  Plant."
      Provided to EER  Corporation by Volund USA Ltd.  on May  19.  1988.

21.   EER Corporation and Radian Corporation.   "Municipal  Waste Combustors -
      Background  and  Information  for  Proposed   Guidelines  for  Existing
      Facilities."   EPA-450/3-89-27e.  August 1989.

22.   Radian.  Minutes  from  December  10,  1987 meeting between Westinghouse,
      EPA.  EER. and  Radian  at  N.C.  Mutual  Building,  Durham.  NC.

23.   Beachler. D.,  Pompelia.  D.M.. and Weldon. J.   "Bay  County.  Florida  Waste-
      to-Energy Facility Air  Emission Tests."  Presented at NITEP Conference
      on Municipal  Waste Incinerator, Montreal, Quebec.   October  1-2, 1987.

24.   Roy F. Weston,  Inc.   "Compliance  Test Results  -  Pigeon  Point,  DE Energy
      Generating Facility."  January 1988.

25.   Response  to   Clean  Air Act  Section  114  Information  Questionnaire.
      Results  of  Non-criteria Pollutant  Testing  Performed  at  Pope-Douglas
      Waste to Energy  Facility.  July 1987.  Provided to  EPA on May  9,  1988.

26.   Telecon.  D.  Scales.  Consumat Systems and P.  Schindler, EER Corporation.
      June 1.  1988.

27.   New  York  DEC.    "Phase   I  Resource  Recovery  Facility  Emission
      Characterization Study  - Overview Report."  May 1987.

28.   Response  to  Clean Air Act  Section  114  Information  Questionnaire.
      Results  of  Compliance  Testing  Performed at  Windham Energy  facility.
      Willamantic.  CT.  May  18-19,  1982.  Provided  to EPA on July 11. 1988.
                                     4-2

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29.   "Municipal  Waste  Combustion,  Multi-Pollutant  Study,  Emission  Test
      Report, Maine  Energy Recovery  Company,  Refuse-Derived Fuel  Facility,
      Biddeford, Maine.  Volume I,  Summary  of Results."   EPA-600/8-89-064a.
      July 1989.

30.   Barsin, J.A., Bloomer, T.M.,  Gonyeau. J.A., and  P.K.  Graika.   "Initial
      Operating  Results of  Coal-Fired Steam  Generators  Converted to  100%
      Refuse-Derived-Fuel."   Presented  at  the  American Flame  Research
      Committee  1987  International  Symposium of Hazardous.  Municipal,  and
      Other Wastes.  Palm Springs,  CA.  November 2-4. 1987.

31.   Interpoll  Laboratories.   "NSP Red Wing RDF Plant - Results of March 1988
      Compliance Test  on Boiler No.  2."  May 10. 1988.

32.   Nelson, L.P., Energy  and  Environmental Research Corporation.  "Municipal
      Waste Combustion Assessment:   Fluidized  Bed Combustion."   EPA-600/8-89-
      061.  July 1989.

33.   Interpoll  Laboratories.   "Results of the November 3-6, 1987 Performance
      Test on the  No.  2  RDF  and  Sludge  Incinerator at  the  WLSSD Plant  in
      Duluth. Minnesota."  Interpoll  Report No. 7-2443.  April  25. 1988.

34.   Clean Air  Engineering.  "Results  of  Diagnostic and Compliance Testing at
      NSP French Island Generating  Facility  Conducted  May  17-19.  1988."   July
      1988.

35.   Kullendorf, A.,  Oscarsson,  B.,  and  Rollan, C.   "Gotaverken CFB  Boiler:
      An Environmentally Safe Solution to  Our  Waste  Disposal  Crisis."   Fourth
      Solid  Waste  Management and  Materials  Conference.  New  York.   January
      1988.
                                     4-3

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                                 TECHNICAL REPORT DATA
                               rrad JntiniCtiom on "><• rrtrnr bf/fr (
    EPA-600/8-89_i057
  T IT L I ANt< Vt-l' T i » i. I
                     —i
    Municipal Waste Combustion Assessment: Combustion   ' .,»•<"•>
    Control at New Facilities
                                                                August 1989
                                                        .fc »•' f **' O H »v . t* i, (  *- (, (• f
    P.J. Schindler
9 PS ff O«MING OKGANIjATlOK *AM€ AMD AOO"CSS

    Energy and Environmental Research Corporation
    3622 Lyckan Parkway, Suite 5006
    Durham. NC  27707
68-03-3365
1 3. S»-ONSO«ING AGtNCY NAUC Af
-------