BACKGROUND INFORMATION
                          FOR
       PROPOSED NEW-SOURCE
                 PERFORMANCE
                  STANDARDS:

                    0 • • • e
              Steam Generators
                    Incinerators
          Portland Cement Plants
               Nitric Acid Plants
             Su If uric Acid Plants
U. S. ENVIRONMENTAL PROTECTION AGENCY

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      BACKGROUND INFORMATION
              FOR PROPOSED
NEW-SOURCE PERFORMANCE STANDARDS:

              Steam Generators
                 Incinerators
           Portland Cement Plants
              Nitric Acid Plants
             Sulfuric Acid Plants
            ENVIRONMENTAL PROTECTION AGENCY
               Office of Air Programs
         Research Triangle Park, North Carolina
                  August 1971

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Office of Air Programs Technical  Report No.  APTD-0711

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                             CONTENTS
                                                                         Page
INTRODUCTION	    .1
TECHNICAL REPORT NO.  1  -  STEAM  GENERATORS  	    3
    Summary of Proposed Standards  	    3
        Particulate Matter   	    3
        Sulfur Dioxide     	    4
        Nitrogen Oxides 	    4
    Emissions  from Steam  Generators  	    5
    Justification of Proposed Standards  	    8
        Particulate Matter   	    9
        Sulfur Dioxide   	   10
        Nitrogen Oxides 	   13
    Economic Impact of  Proposed Standards  	   14
        Particulate Matter	   15
        Sulfur Dioxide   	   16
        Nitrogen Oxides 	   16
    References	   17
TECHNICAL REPORT NO. 2  -  INCINERATORS  	   19
    Summary of Proposed Standards  	  '19
    Emissions from Incinerators 	   20
    Justification of Proposed Standards  	  ....   21
    Economic Impact of Proposed Standards  	   23
    References	   25
TECHNICAL REPORT NO. 3 -  PORTLAND  CEMENT PLANTS	'.  .  .  .   27
    Summary of Proposed Standards  	   27

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        Particulate Matter from Kilns 	  27
        Participate Matter from Clinker Coolers	27
        Participate Matter from Other Equipment 	  28
    Emissions from Portland Cement Plants 	  28
    Justification of Proposed Standards 	  30
        Particulate Matter from Kilns and Clinker Coolers 	  30
        Particulate Matter from Other Equipment 	  31
    Economic Impact of Proposed Standards 	  32
    References	34
TECHNICAL REPORT NO. 4 - NITRIC ACID PLANTS	37
    Summary of Proposed Standards ... 	  37
    Emissions from Nitric Acid Plants 	  38
    Justification of Proposed Standards 	  39
    Economic Impact of Proposed Standards 	  41
    References  	   ^
TECHNICAL REPORT NO. 5 - SULFURIC ACID PLANTS	43
    Summary of Proposed Standards 	  43
        Sulfur Dioxide  	  43
        Acid Mist	43
    Emissions from Sulfuric Acid Plants 	  44
    Justification of Proposed Standards 	  45
        Sulfur Dioxide	45
        Acid Mist	47
    Economic Impact of Proposed Standards 	  49
    References	50
                                         IV

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                             INTRODUCTION

This document provides  background  information on the derivation of the
proposed new-source performance  standards and their economic impact
on the construction and operation  of  new steam  generators, municipal
incinerators, sulfuric  and  nitric  acid manufacturing facilities, and
Portland cement plants.   The  proposed standards, published in the
Federal Register under  Title  42  CFR Part 466, are being distributed
concurrently with this  document.   The information presented herein was
prepared for the purpose of facilitating review and comment prior to
promulgation of the standards.

The performance standards were developed after  consultation with plant
owners and operators, appropriate  advisory committees, equipment
designers, independent  experts,  and Federal departments and agencies.
Review meetings were held, with the Federal Agency Liaison Committee
and the National  Air Pollution Control Techniques Advisory Committee.
The proposed standards  reflect consideration of comments provided by
these committees and by other individuals having knowledge regarding
the control  of pollution from the  specific source categories.

The National Air Pollution  Control Techniques Advisory Committee is
made up of 16 persons who are knowledgeable concerning air quality, air
pollution sources, and  technology  for the control of air pollutants.
The membership includes state and  local  control officials, industrial
representatives, university professors,  and engineering consultants.

                                         1

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Members are appointed by the EPA Administrator pursuant  to  Section
117 (d), (e),  and (f) of the Clean Air Amendments  of 1970,  Public
Law 91-604.  In addition, persons with specific expertise in the
respective source categories participated in the meeting of the Advisory
Commi ttee.

The Federal Agency Liaison Committee includes persons knowledgeable
concerning air pollution control practices as they affect Federal
facilities and the nation's commerce.  The committee is  made up of
representatives of 19 Federal agencies.

The promulgation of standards of performance for new stationary
sources under  Section 111  of the Clean Air Act does  not  prevent
state or local  jurisdictions from adopting more stringent emission
limitations for these same sources.   In heavily polluted areas, more
restrictive standards, including a complete ban on construction, may
be necessary in order to achieve National  Ambient  Air Quality Standards.
Section 116 of the Act provides specific authorization to states and
other political subdivisions to enact such standards and limitations.

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               TECHNICAL REPORT  NO. 1 -
                    STEAM  GENERATORS
SUMMARY  OF PROPOSED STANDARDS

Standards of performance are being proposed for new fossil-fuel-fired
steam-generating units with a capacity  greater than 250 million Btu
per hour heat input.  The proposed standards include emission limitations
for particulates (including visible emissions), sulfur dioxide, and
nitrogen oxides.  The particulate limits are. based on the EPA sampling
procedure, which employs a dry filter as well as wet  impingement  collectors,


The proposed standards would limit emissions to the atmosphere as follows:


Particulate Matter

    1.  No more than 0.2 pound of particulates per million  Btu heat input,
       or 0.36 gram per million calories.

    2.  Visible emissions shall not be darker in shade than that  designated
       as No.  1 on the Ringelmann Scale or 20 percent equivalent opacity,
       except  for 2 minutes in any one hour when emissions may be as
       great as No. 2 on the Ringelmann Scale or 40 percent equivalent
       opacity.

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Sulfur Dioxide





    1.  No more than 0.8 pound  of sulfur  dioxide  per million  Btu  heat



        input,  or 1.4 grams  per million calories, when  liquid fossil



        fuel  is fired.





    2.  No more than 1.2 pounds of sulfur dioxide per million Btu heat  input,



        or 2.1  grams per million calories, when.sol id fossil  fuel is fired.







Nitrogen Oxides





    1.  No more than 0.20 pound of nitrogen oxides (measured as N02)



        per million Btu heat input, or 0.36  gram  per  million  calories,



        when gaseous fossil  fuel is fired.





    2.  No more than 0.30 pound of nitrogen  oxides  (measured  as  N02)



        per million Btu heat input, or 0.54  gram  per  million  calories,



        when.liquid fossil fuel is fired.





    3.  No more than 0.70 pound of nitrogen  oxides  (measured  as  N02)



        per million Btu heat input, or 1.26  grams per million calories,



        when solid  fossil fuel   is fired.







The proposed particulate standard is equivalent to  a  stack concentration



level of 0.12  to 0.13 grain per standard  cubic foot corrected to 15



percent excess air.  To burn most fuel oils  (less than  0.10 percent ash),



no particulate controls would be required.   Coal-fired  steam  generators



would, however, require high-efficiency particulate collectors.   The



visible emissions standard is compatible  with  the mass  emission  limit;



if particulates are at or below 0.20 pound per million  Btu, visible emissions



normally will  be less than 20 percent opacity.

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The proposed SCL limits  can  be  achieved  by  the  use of low-sulfur fuels,
stack-gas cleaning systems,  or  combinations of  the two.  No stack-gas
cleaning would be required for  high-grade coal  of 0.7 percent sulfur or
less, or for fuel  oil  of 0.8 percent  sulfur or  less.  The corresponding
stack-gas concentration  for  coal  is 620  ppm and for oil, 440 ppm, both
referenced to 15 percent excess  air.
The proposed nitrogen  oxides standards correspond to 165 ppm for burning
natural gas, 227 ppm for fuel oil,  and 525  ppm  for high-grade coal, all
referenced to 15 percent excess  air.

EMISSIONS  FROM STEAM GENERATORS
Particulate collectors are common to  coal-fired boilers and are sometimes
used with oil-fired units.   Coal-fired steam  generators tend to use
mechanical collectors  and electrostatic  precipitators of varying efficiencies.
If coal-fired operations were completely uncontrolled, particulate emissions
would range from 6 to  10 pounds  per million Btu.  At most existing in-
stallations, emissions range from 1 to 4 pounds per million Btu.  Partic-
ulates from oil-fired  steam  generators are  seldom controlled except for
mechanical collectors, which are used chiefly during periods of soot
blowing.  Particulate  emissions  from  uncontrolled oil-fired steam
generators normally range from  0.04 to 0.06 pound per million Btu, with
most of the particulates traceable to inorganic ash in the oil.  Unless
the ash content of the oil  is excessive  (greater than  0.4  percent by
weight), or unless there is  poor combustion,  particulate emissions are
well below the limits  of the standard.

Most state and local regulations limit particulate emissions from coal-
fired steam generators to a  level between 0.10  and 0.80 pound per million

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Btu heat input.   A few jurisdictions' have more stringent restrictions
for oil-fired equipment.   One local  agency has established  limits  for
all three pollutants (particulates,  S02, and NOX) from new steam genera-
tors at such a low level  that solid  and liquid fuel  utilization is
precluded.  In most instances, particulate limits that are  more restrictive
than the performance standard of 0.20 pound per million Btu heat input
are based on American Society of Mechanical Engineers  (ASME)  testing
procedures that are different from the specified EPA test method.

Although no definite correlation between these methods has been
established, it appears that the proposed new-source standard is
consistent with a level of about 0.07 pound per million Btu if the
ASME test procedure is used as the reference test method.  Despite
the  numerical  difference, both standards require about the same
degree of control.

With existing fuel  sulfur  levels, uncontrolled  S02  emissions range
from 1 to 7 pounds  per million Btu.   Few existing steam generators
have stack-gas desulfurization  except  for  the  demonstration
installations on which these standards are based.  Several  state and
local  regulations limit S0? emissions from combustion sources by
restricting sulfur  in fuels.  Stack-gas desulfurization usually can
be utilized at the  option of the operator.  Fuel sulfur limits of
0.50 to 1.0 percent (0.5 to 1.4 pounds per million Btu) have been
established in a number of areas of the country.

Most of  the  steam generators  in the United States were  not designed
specifically  to  reduce nitrogen oxides emissions.   Nitrogen oxides
emissions tend to vary with  boiler  design, and  range  from  0.3  to  2.0

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pounds per million Btu.   Only a few states and local  jurisdictions



restrict NO  emissions.   Limits range from 0.15 to 0.60 pound per
           A


million Btu heat input for gaseous fuels, and from 0.13 to 0.60 pound



per million Btu for liquid fuels.   These regulations  have only recently



been promulgated, and there has been little experience with their enforce-



ment.  The performance standards for gaseous and liquid fuels are



slightly higher than the minimum levels for local  agencies.  Regulations



for oxides of nitrogen produced by solid-fuel combustion have not as



yet been adopted by states or local jurisdictions.







In developing performance standards for steam generators, consideration



was given to the availability and cost of fuels and control techniques



and to effects on the economics of producing electric power.  The major



considerations were:





     The necessity of making use of all the principal fossil fuels - coal.,.



     oil, and natural gas.  The cleanest fuels are in limited supply.   It



     is estimated that the use of coal will increase at a much greater



     rate over the next 30 years than will  that of residual oil and natural



     gas.








     The desirability of setting standards  that would allow the use of



     combination control systems to collect both  particulates and sulfur



     dioxide.  It does not appear that the  particulate/S02 systems under



     study  are capable -of collecting nitrogen oxides.







     The desirability of setting sulfur dioxide standards  that would allow



      the use of  low-sulfur fuels as well  as  fuel  cleaning, stack-nas



     cleaning, and equipment modifications.

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    The fact that most low-sulfur fuel  oil  or crude oil  will  have  to  be
    imported from Alaska or from foreign countries.   Substantial quantities
    of desulfurized fuel oil  will  be available from Caribbean facilities,
    several of which will go on-stream in 1971 and  1972.

    The fact that naturally occurring low-sulfur coal  is  restricted for
    the most part to the Rocky Mountain area, so that shipping costs  to
    eastern and midwestern power stations can be appreciable.  Coal-
    cleaning techniques can be used to remove substantial  portions of
    sulfur and ash from some coals, but the processes are  highly dependent
    on the make-up of the coal.

    The fact that stack-gas desulfurization processes have only recently
    been developed to the point at which they can be applied  to steam
    generators.  The first new steam generators to  be affected by  the
    standards will be put into operation in 1975 and 1976.  In many
    cases owners and operators can delay decisions  on air pollution control
    equipment for a year or longer after the steam  generator  has been
    designed.  At that time there should be a greater number  of options
    for sulfur dioxide control schemes from which to choose.

JUSTIFICATION OF PROPOSED STANDARDS

The proposed performance standards  are. based on  inspections and tests of
prototype and full-scale control  systems, on consultations with state and
local  officials and operators  and  designers  of steam generators and control
systems,  on EPA surveys of available combustion  fuels, and on  review  of the
literature.  Essentially all  of the technology applicable  to  the subject
was developed in the United States.

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The adequately demonstrated techniques  include the use of electrostatic
precipitators for particulate removal,  low-sulfur fuels and  flue-gas
cleaning for sulfur dioxide removal,  and combustion modifications  for
nitrogen oxides abatement.   For the most part, these systems have  been
developed independently for each pollutant.   The best systems for  sulfur
dioxide and particulate removal have  not necessarily been operated on
the same coal-fired steam generators.   Many  of the nitrogen  oxides control
techniques have been developed on units fired with low-sulfur fuel oil
and natural gas, which had  no requirements for sulfur dioxide or particulate
control.

Particulate Matter
The particulate limits are  based primarily on EPA tests of existing
electrostatic precipitators that were reported to have high  collection
efficiencies.  Seven precipitator-equipped steam generators  were tested
during coal burning using- the EPA test method.  Two of the installations
were shown to meet the particulate limit, and two more barely exceeded
the limit at 0.21 pound per million Btu.  At the most effective precinitators
only a trace of the emissions was visible.

Tests of the one :>crubber showed particulate emissions of 0.32 pound per
million Btu.   The marble-bed scrubber, however, was designed principally
for S02 removal rather than high-efficiency particulate control.  Infor-
mation obtained from various pilot-scale test programs indicates  that
advanced scrubber designs can  achieve the particulate standard of perfor-
mance.  Full-scale scrubbers are now being installed at large steam
generators.  They have been designed to meet particulate levels that  are
consistent with the standard.

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To date no full-scale fabric filters have been demonstrated on coal-fired
steam generators, although two such units are scheduled to be installed at
a New Mexico power station.  Experience with industrial operations would
indicate that baghouses could be employed to meet the particulate limit of
the standards.
The results cited are based on the EPA sampling method, which utilizes a
dry filter and wet impingement collectors.  Most of the data available
in the literature are based on the American Society of Mechanical Engineers
(ASME) test method, which generally reflects lower particulate loadings than
the EPA method.  Reported values with the ASME method range bel.ow 0.05
pound per million Btu for high-efficiency electrostatic precipitators.

Visible emissions were recorded at the seven coal-fired installations
where particulates were measured.  At the two plants that met the proposed
standard, as well as at the two steam generators that barely exceeded the
standard, visible emissions were less than 20 percent opacity.  No black
smoke was observed at any of the tested installations.

Sulfur Dioxide
The standards for sulfur dioxide are based on limited demonstrations
of stack-gas desulfurization processes and on the availability of low-
sulfur fuels.  At this time only the lime-slurry scrubbing system is
considered adequately demonstrated on large steam generators.  Three other
processes have been shown capable of continuous operation at smaller
installations.

A lime-slurry scrubbing system, demonstrated for 6 months on two coal-
fired units of 125 and 140 mW capacity, approached the S02 emission limit
10

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of 1.2 pounds per million Btu.   This operation represents 73 percent re-


moval of S0? from fuel  gases in instances where the bituminous coal  con-


tains 3.0 percent sulfur by weight.   One of the units was selected for


the EPA test program, resulting in a verification of the S02 removal


performance reported by the control  system manufacturer and facility


operator.  These lime-slurry systems have been operated at greater S02


removal efficiency, but only for limited periods, so that sustained


operation at this level is not considered to have been adequately demon-


strated.   A prototype unit, however, employing a dual-bed design, has


achieved emission levels as low as 1.0 pound per million Btu heat input


for an extended period of time.2 This system is also applicable to steam


generators burning fuel oil.  The demonstrated removal efficiency (76


percent), applied to a typical  fuel  oil of 2.5 percent sulfur content,


results in an emission level of 0.7 pound per million Btu heat input,


which  is below  the standard of performance.   Lims-scrubbing systems are


essentially  throwaway  processes that produce  significant quantities of


solid  waste.  For a  3.0-percent-sulfur  coal,  the additional wastes  are


roughly  equal to the ash  generated  from burning  coal.



Some other processes have  been utilized  on pilot or  prototype  installations


to  the  point that there  is  reasonable assurance  of  successful  operation, but


they are not deemed  adequately demonstrated for  the  purposes  of  these


standards.   In  Sweden, another lime-slurry system,  utilizing  a different         ^
                                                 I A KT                        •"* r\ C'l^f

scrubber design, has been  demonstrated  on a 70,JS|f>-Btu-per-hour  oil-fired       3^


unit at  emission values  of  0.25 pound per million  Btu  heat  input (95 percent


S02  removal) without interruption of steam generator operation over the

             3
past 3 years.   An integrated  catalytic-oxidation  system has  been operated


at  an  emission  level of  0.5 pound per million Btu  heat  input  during a nrogram


that accumulated some  7000  hours of operation on coal-generated  flue gases
                                                                              11

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with a volumetric flow rate equivalent to a 120 JS8-Btu-per-hour steam- tj
electric unit.    Sodium sulfite/bisulfite scrubbing has  been continuously
operated at sulfur dioxide removal  efficiencies in excess  of 90 percent
on a sulfuric acid plant with a tail-gas volume flow rate  equivalent to a
    vM^                                 5
220;S3&-Btu-per-hour steam-electric unit.   This  system  has  been installed
at a^p?000,000-Btu-per-hour oil-fired power plant in Japan, which is scheduled
for operation in late 1971.  To date, magnesium oxide-slurry scrubbing has
been demonstrated only on pilot-scale tests.   A full-scale maanesium
oxide scrubbing system is being installed to serve a 4^LiIJU jUiitfJ-Btu-per-
hour steam-electric generator and is scheduled for operation in October
1971.

Coal and fuel oil of low sulfur content and natural gas can be used to
satisfy the standards at many new steam generators.  It is not expected,
however, that there will be enough low-sulfur fuel to supply all new steam
generators as well as existing sources requiring S02 control under state
implementation plans.  In addition, transportation costs in many areas
may make these fuels more expensive than stack-gas desulfurization.

Principal sources of low-sulfur crude oil are Africa, Indonesia, Canada,
and Alaska.  Because South American crudes are generally high in sulfur,
several desulfurization plants have recently been put into operation in
Central America to satisfy fuel specifications of the eastern United States.
To ensure reasonable supplies of 0.8-percent-sulfur oil to meet the new-
source performance standard, some increases in desulfurization capacity
will be required, as well as growth of low-sulfur imports and extensive
use of blending.
Host of the naturally occurring United States coal of 0.7 nercent sulfur
or less is  located in the Rocky Mountain area.  Shipping costs have thus

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far precluded widespread  use  in  the  midwest  and  on  the  east  coast.   In

the eastern United States,  some  coals  could  be upgraded to meet  the  standard.

In other areas that are remote  from  low-sulfur-coal  production sites, however,

stack-gas cleaning probably will  be  the  least expensive method for many

operators to meet the standard.



Nitrogen Oxides


Nitrogen oxides standards of  performance for liquid  and gaseous  fuels

were based on tests on units  having  modifications to the combustion

process.  Combustion modifications of  primary importance include  flue-

gas recirculation, off-stoichiometric  combustion techniques,  low  excess

combustion air, and reduced combustion air preheat.   Flexibility  in

application of these methods  will  be required for compliance  with the

standards of performance.  Flue-gas  recirculation and offrstoichiometric

combustion individually have  the potential  of meeting the standards  for

liquid and gaseous fuels.
Published test data from six tangentially  fired  units  of^.DOOTWTO1 to
 ?.3*f^
IgggggSISL Btu per hour (320 to 330 mW)  capacity  utilizing  flue-gas

recirculation, and from seven units of  capacities  ranqing  from
-k *r.rv/0*
r^f-"1 rftftfffl n n P t u per hour (125 to 750 mW)  with off-stoichiometric

combustion techniques, indicate routine operations at  or below the required

emission  level of 0.2 pound per million Btu for  gaseous  fuels. '    An  EPA

test on one of the six tangentially fired  units  utilizing  flue-gas recircu-

lation verified the published data for  these units burning natural  gas  and

fuel oil.  Off-stoichiometric combustion is generally  utilized to  limit

emissions of nitrogen oxides from steam generators burning liquid  fuels.

Emissions from eight oil-fired units ranging in  capacity from
   ssons  r
   7, S ~n ( 0 •
to ^jf.QfiBaaa. Btu per hour (132 to 480 mW) were reported in various
                                                                             13

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publications  at levels  below  the  standard of performance for liquid



fuels.  '    Combined  methods show  promise of much  lower emission levels,



although  these techniques  have  not  been adequately demonstrated.







The NO  standard for solid fuels  is based on results  from  tangentially
      A


fired units burning  coal.   Four tangentially fired units burning  bituminous



coal, which were tested by EPA, had emissions  of  nitrogen  oxides  that were



well below the required level  of 0.7 pound  per million Btu.  Published data



from numerous sources,  and other test results  from steam-generator manufac-



turers, indicate comparable results for tangential firing, and considerably



higher levels for wall-fired  units.?>8   Combustion modifications have not



as yet been applied  to  solid-fuel units to  any extent.   The  fact  that



tangential firing alone reduces NO  emissions  in  units burning coal, however,
                                  A


indicates that combustion  modifications that have been incorporated  in units



burning natural gas  and fuel  oil  will produce  similar reductions  with solid



fuels.  In addition, experience gained from gas-  and  oil-fired units shows



that there is little difference in NO  production between  tangentially
                                     A


fired and wall<-.fired steam generators when  combustion modifications are



employed.  Emission  levels are anticipated  to  be  considerably  lower  than  the



standard after combined modifications have  been instituted.  Fuel-constituent



nitrogen appears to  be  of secondary importance in the emission of NO  when
                                                                    /\


combustion modifications are  utilized.
ECONOMIC IMPACT  OF PROPOSED STANDARDS




Approximately 35 steam-electric generation units  and 40 industrial  steam



generators are oresently being installed in the United States  annually.



Some 96 percent of the total capacity of new units greater than  250



million Btu heat per hour input will be utilized  by the electrical  utility




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industry.   Since construction of steam generators  requires  from  3  to



5 years, a substantial  portion of the economic  impact  will  be  delayed.






The economics involved  with controlling particulate,  S02,  and  NOX



emissions  will  vary, depending on the (1)  availability of  low-sulfur



fuels in the geographical  location,  (2) fuel,  and  (3)  control  techniques



selected.   The capital  investment required to  control  these three



pollutants will  seldom  exceed 25 percent of the total  installed  cost



of a steam-electric generation unit.   Since units  burning  gaseous  fuels



need only  control  NO ,  the capital  investment  will  amount  to only  5  percent
                    J\


of the installed cost.   The corresponding increases in operating costs



for electrical  production  will range  from 15 to 40 percent for solid- and



liquid-fuel units, and  only 4 percent for gaseous  fuels.   More stringent



requirements  to meet ambient air quality standards as specified by  state



implementation plans (Section 110 of  the Clean Air Act) will force control



costs much higher in some  areas.






Particulate Matter





The present trend involves the installation of high-efficiency electrostatic



precipitators of near the  same size as those necessary to  meet the standard



of performance.   Hence, there is a marginal additional cost resulting from



the particulate standard.   The total  costs, however,  reflect an  allotment



for an increase of 6 percent in the total  capital  investment and 4 percent



in operating costs.  These costs exceed those  for  precipitators  alone and



are high enough to include installation of scrubber systems and  baghouses.





The standard of performance is sensitive to cost/benefit analysis.  The



standard is based on high-efficiency  electrostatic precipitators,  scrubbers,



and baghouse collectors.  The use of  less efficient precipitators  and scrubbers
                                                                             1!

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would require that the standard be relaxed by a factor of 2  with  a
savings of up to 3 percent of the total  plant initial  investment.

Sulfur Dioxide

Control costs for SCL are by far the highest of the three pollutants,  with
increases of about 10 percent in capital  investment and 7 to 30 percent in
operating costs.  Sulfur dioxide control  is not normally practiced  by  the
steam-generation industry and will result in a direct additional  cost  in
most areas.  The reimbursements for salable by-products, such as  elemental
sulfur and sulfuric acid, were not included as credits in the cost
estimates because of the market variabilities involved.  In  addition,  the
cost for disposal of spent reagents incurred by some processes was  not con-
sidered in any depth.

The standards of performance are insensitive to cost/benefit analysis  when
stack-gas cleaning is employed in that it is the only control system
available.   Since the availability of low-sulfur fuel varies with the location
of  the plant, it  is  not  possible  to analyze  the cost of this control strategy.
The decision to use  low-sulfur fuels instead of flue-gas cleaning may force the
opening of new mines to  meet demand.

Nitrogen Oxides

Nitrogen oxides combustion-modification economics are similar to those
for electrostatic precipitators, with capital .investment increases  approach-
ing 7  percent as  a maximum,  and  elevation  in operating  costs  reaching 4  percent.
The capital  investment  should  decline to  0  percent, however,  as combustion-
modification becomes common practice and  not a special  modification.   A few
 coal-fired steam generator designs  inherently  produce  high  levels  of  NOX,  and  it
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is unlikely that some of these  can  be modified to meet the standards.  Three



of the four major steam-generator manufacturers would have to modify their



coal-fired designs in order  to  realize  the  NO  limits of the standard.
                                            A


The fourth manufacturer's design can meet the standards with no  increase



in cost, however.  This manufacturer presently accounts for 40 percent of



the coal-fired steam-generator  market.   All  four firms sell boilers  that



can meet the limits proposed for gas and oil burning.








REFERENCES





1.  Martin, J. L., W. C. Taylor, and A. L.  Plumley.   The C-E Air Pollution



    Control System.  Combustion Engineering, Inc.  Presented at  1970  Industrial



    Coal Conference, University of  Kentucky, Lexington, April 8-9,  1970.




2.  Communication from Combustion Engineering,  Inc.   Windsor, Conn.,



    April 30, 1971.



3.  Bahco Lime Addition - Wet Scrubbing Process.   Office of Air  Programs



    (internal briefing document), Division of Control  Systems, Environmental



    Protection Agency, 1971.



4.  Sites,  J. G.,  Jr. et al.  Removing S02 from Flue Gas.   Chemical  Engineering



    Progress, 65J10):74-79,  October 1969.



5.  Communication  from Wellman-Power Gas, Lakeland,  Fla.,  April  5,  1971.



6.  Bagwell,  F.  A.,  et al.  Boiler  Operation for Reduced  Nitric  Oxide



    Emissions.   Presented at the 64th  Annual Meeting of  the  Air  Pollution



    Control Association, Atlantic City, New Jersey,  June  27  -  July  1, 1971.



7.  Supporting Document on NO  Emissions and Their Control  for  Steam-Electric



    Boilers.  Linden, New Jersey, ESSO Research and  Engineering  Co., April  1971,



8.  Communication  from Combustion Engineering,  Inc., Windsor,  Conn.,



    April  30, 1971.
                                                                             17

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                                                       .2  -
SUMMARY OF PROPOSED STANDARDS

Standards of performance  are being proposed that will  limit participate
emissions from new municipal incinerators with a capacity greater than
50 tons per day (24-hour).  The particulate limits are based on the EPA
sampling procedure, which employs a dry filter as well as wet impingement
collectors.

The standards of performance would apply only to those incinerators used
to burn predominantly municipal solid wastes, e.g., household and commercial
paper, cardboard, garbage,  and yard wastes.  The standards will not apply
to incinerators used exclusively to burn sewage sludge, pathological  wastes,
sawdust, or other specialized trade wastes.
The proposed standard would limit particulate emissions to the atmosphere
as follows:
     No more than 0.10 grain of particulates per standard cubic foot (scf)
     of dry flue gases, corrected to 12 percent carbon dioxide (C02).

For burning of typical solid wastes in  the United States, the limit of 0.10
grain per scf, corrected  to 12 percent  C0£, corresponds to the production
of 1.9 pounds of particulates per ton of solid wastes charged to the

                                         19

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incinerator,  and about 0.17  pound  of  particulates per 1000 pounds of flue
gas, corrected to 50 percent excess air.
EMISSIONS FROM INCINERATORS
An uncontrolled incinerator will  emit  considerably more particulates than
the standard allows.   Available data indicate  that, on the average, uncon-
trolled furnace gases contain about  1  grain  of particulates  per scf
dry gas at 12 percent C02.1>2  For average domestic solid waste,  this
corresponds to about 19 pounds of particulates per ton of wastes  burned.
In most cases, these data were obtained  using  sampling methods different
from the EPA method that is to be used to  determine compliance.   Gases
from existing furnaces, therefore, may contain somewhat more than 1
grain of particulate matter per scf.   The  range of 15 to 30  pounds of
particulates per ton of waste charged  probably covers most existing
incinerators of conventional design.   The  average particulate collection
efficiency required to meet the standard is  about 90 to 95 percent, based
on the above uncontrolled emission rate.

State and local regulations are, in  some cases, more stringent than the
proposed standard.  Typical standards  range  from 0.03 to 0.3 grain per
scf, corrected to 12 percent C02-  Several state and local standards are
based on particulate test methods that differ  from the  EPA technique.
Although no definite correlation between these methods  has been established,
it appears that the proposed standard  is not inconsistent with the most
stringent state- standards  in existence,  which  are  based  on  the  test  pro-
cedure of the American Society of Mechanical Engineers.  Despite  the numerical
difference, both standards will require  approximately the same degree of
particulate control.

20

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Some state and local  standards  are corrected to a reference base of 50
percent excess air rather  than  12 percent COp.  Others are given in terms
of mass emissions  per unit weight of solid waste charged to the incinerator.
All of these units can be  interrelated  if suitable gas and solid waste
analyses are available.
JUSTIFICATION OF PROPOSED STANDARDS

The proposed performance  standards  are  based  on a study of incinerators in
the United States  and  Europe.   Information was obtained by inspections
and stack tests of operating  plants and by consultation with designers,.
plant operators, and state and local  control  officials.  The Systems Study
of Air Pollution from  Municipal  IncinerationJ performed under contract by
Arthur D. Little,  Inc.,  provided a  comprehensive review of American
operations and incinerator technology.   The study showed that almost all
existing municipal  incinerators  release excessive amounts of particulates
and that, until recently, none were equipped  with high-efficiency particulate
collectors.

Investigations by  EPA  engineers  show that electrostatic precipitators,
fabric filters, and high-energy  scrubbers are being utilized to control
particulates from  municipal incinerators.  Tests using the EPA method show
that particulate emissions from  precipitators are within the limits of the
proposed standard.   European  tests  and  pilot  studies in this country also
indicate that fabric filters  will  provide sufficient particulate control
to meet the standard.   On one recent installation of a venturi scrubber,
the designer guaranteed  particulate emission  levels consistent with the
proposed standard.
                                                                             21

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Of the approximately 250 municipal  incinerators in the United States, only 6
are equipped with high-efficiency particulate collectors.   Five plants have
electrostatic precipitators, and one is controlled with a high-energy
venturi scrubber.  Two of the domestic precipitators were tested by EPA
and EPA contractors.  Particulate emissions ranged from 0.07 to 0.09 grain
                                                    i
per scf dry gas, corrected to 12 percent CO*-  These values were the average
of three 2-hour sampling runs at each plant.  One of the values was con-
firmed in an independent test in which the EPA sampling method was used.
At one of the plants, previous tests with a similar sampling method indicated
much higher values.  Even though the discrepancy has not been explained,
the EPA results are considered valid.

Several incinerators in Europe and Japan are equipped with electrostatic
precipitators designed to achieve an efficiency of better than 99.0 per-
cent in removing particulates.  Two European plants, one in Germany
(with an efficiency of 99 percent) and one in Sweden (with an efficiency
of 98 percent), were tested by EPA personnel.  Emissions averaged,
respectively, 0.05 and 0.07 grain per scf of dry gas at 12 percent C02-
The German plant was tested by European methods both before and during
the EPA tests.  Results of all tests -  by both European and EPA methods -
are in approximate agreement.

The U.S. plants tested are of both refractory and water-wall design,
and capacities range from 300 to 400 tons of municipal refuse per day.
The European incinerators were of water-wall design, with capacities
ranging from 220 to 400 tons of municipal refuse per day.

The  few existing data on municipal incinerators equipped with  baghouses
indicate  that  these devices also could  be used to meet the  standard.   One
 22

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small Swiss unit (36 tons per day)   with  a  fabric filter was tested with
European sampling procedures; measured  values  averaged 0.04 grain per scf,
                            3
corrected to 12 percent CO .    Lower emissions  of particulates are  re-
ported for a small  pilot installation operated  by the City of Pasadena
(California) in 1960.    The first  large municipal incinerators (greater
than 50 tons per day)  equipped with  baghouses will be put into service
in late 1971 in the United States  and Switzerland.

Test data are not yet  available for  the one  high-energy scrubber in use.
The venturi scrubber is operated with a 12-inch  (water column) pressure
drop, and it serves a  240-ton-per-day incinerator.  The designer has guaranteed
an emission level consistent  with  the performance standard.

ECONOMIC  IMPACT OF  PROPOSED STANDARDS
Over the next few years it is estimated that 20  to 25 new municipal
incinerator furnaces will be  constructed annually in the United States.
The actual rate of construction may  vary considerably from this
estimate depending on  the availability  of  alternative solid waste disposal
methods.

In order to meet the limits of the performance  standards; new incinerators
of conventional design will have to  be  equipped with high-efficiency
particulate collectors.  In addition the incinerators themselves may
cost more than many existing  units because of  the need to provide optimum
combustion of particulates.  Very  few existing  furnaces are expected to
be modified to the degree that they  will have  to comply with the new source
standard.

Information on the cost of incinerators and  control equipment is derived
primarily from the cited Arthur D. Little  study.  Reported costs are
                                                                            23

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based on extensive review of manufacturers'  quotations,  estimated by
Little to have an accuracy of plus  or minus  20 percent.   Both  total
installed costs and annual  operating costs  are presented.   Installed
costs include the incinerator, excavation,  foundations,  dump  pits,
buildings, and access roads.   Annual  operating costs  include  amortization,
interest, utilities, maintenance,  and wages.

The standard of performance is sensitive to cost/benefit analysis based on
the use of electrostatic precipitators, scrubbers, or baghouse collectors.
If the standard were relaxed by a  factor of 2, capital  and  operating costs
of necessary precipitators or scrubbers would be reduced 30 percent.
Baghouse costs and collection efficiencies  are the same  regardless  of the
standard.  The use of a mechanical  collector would require  that the
standard be relaxed by a factor of 4,  This would halve  capital  costs and
savey.$.50 per capita.  The benefit of increased particulate control
warrants the additional expenditure.

Installed costs for a 100-ton-per-day refractory furnace are  about  $1,000:000
for the incinerator, including about $150,000 for high-efficiency control
equipment.  Installed costs of control equipment are  therefore about  15
percent of the entire plant costs.   For plants with a capacity of 300 tons  per
day, costs decrease to 13 percent  of the incinerator  cost.

For a 100-tpn-per-day water-wall furnace, incinerator costs are about
$4^l^^8 installed,  including about $105,000 for the cost of high-efficiency
control equipment.  Control equipment costs are therefore about 9 percent
of installed costs for the 100-ton-per-day  plant.  This  decreases to about
5 percent for a  300-ton-per-day plant.

-------
The cost of operating the control  equipment  at  the  refractory  furnace
plant ranges from $29,000 (100 tons  per day)  to $65,000  (300 tons  per  day)
per year.  For the water-wall  plant, these costs are  $13,000 (100  tons
per day) and $23,000 (300 tons per day) per  year.

Refuse generation rates as determined by the Office of Solid Wastes
Management, and equipment costs  determined by Arthur  D.  Little, Inc., were used to
calculate per capita control  costs.    Per  capita cost varies with  incinerator
design and capacity and with  the pollution control  equipment employed.
For the examples developed above,  per capita  cost is  less  than about
1 dollar per year, decreasing as furnace capacity increases.


REFERENCES

1.  Systems Study of Air Pollution from Municipal Incineration.   Performed
    under Contract No. CPA-22-69-23  by Arthur D. Little, Inc.  U.  S. DHEW,
    CPEHS, National Air Pollution Control  Administration.   Raleigh, N.C.
    March 1970.

2.  Duprey, R.L.  Compilation of Air Pollutant  Emission  Factors.   U.S. DREW,
    PHS.  National Center for Air Pollution Control.   Durham,  N.C. PHS
    Publication No. AP-42.  1968.   67 p.

3.  Private communication  with the  European Office of American Air Filter
    Co., Amsterdam, Holland.  June 1971.

4.  O'Conner, C., and G. Swinehart.   Baghouse Cures Stack  Effluent.  Power
    Engineering 65(5):58-59,  1961.
                                                                             25

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                  TECHNICAL REPORT NO.  3  -
                  PORTLAND CEMENT PLANTS

SUMMARY OF PROPOSED STANDARDS
Standards of performance are being proposed for all  new wet- and dry-
process  portland cement production facilities.  The  proposed standards
would limit particulate releases.   The  limits are  based on the EPA
particulate sampling procedure, which  includes a dry filter as well  as
wet impingment collectors.

The emission limitations are summarized as follows:

Particulate Matter from Kilns
    1.   No more than 0.30 pound of particulates per  ton of solids fed
        to the kiln, or 0.15 kilogram  of particulates per metric ton of
        solids fed to the kiln.  The feed rate to the kiln is to be
        expressed on a dry basis.

    2.   Visible emissions shall not be  darker in shade than that designated
        as No. 1/2 on the Ringelmann Scale or 10 percent equivalent
        opacity.

Particulate  Matter  from Clinker Coolers
    1.   No more than 0.10 pound of particulates per ton of  solids fed

                                       27

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        to the kiln,  or  0.05  kilogram of particulates per metric ton of
        solids fed  to the  kiln.  The feed rate to the kiln is to be
        expressed on  a dry basis.

    2.  Visible emissions  shall  not be  released to the atmosphere.

Particulate  Matter from Other  Equipment
    Visible  emissions shall not  be released to the atmosphere from any
    other areas of  the plant,  including the raw-material  and finished-
    product  grinding-mill  systems-, raw material, clinker, and finished
    product  storage facilities;  conveyors; transfer points; bagging
    operations; and bulk loading and unloading facilities.  For the
    purposes of this  standard, visible emissions are considered to be
    any emission of greater than 5 percent opacity, or No. 1/4 Ringelmann.
    This limit is only slightly  above the level detectable with the
    human eye.

The proposed visible  emission  standards are compatible with the mass
emission limits for the  kiln  and clinker cooler; observations have
shown that if mass  emissions  are at or  below  the respective limits,
visible emissions will be  at  or  below 10 percent opacity from the kiln
and no emissions will be visible from the clinker cooler.  Obser-
vations of the other  process  equipment  - mills, conveyors, etc. - have
shown that no visible emissions  occur if common dust collection equipment
is installed and properly  maintained.

EMISSIONS FROM PORTLAND  CEMENT PLANTS

Poorly controlled kilns  can release as much as 45 pounds  of particulates
to the atmosphere per ton  of  raw material processed, and  poorly controlled

23

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clinker coolers can release as much as  30 pounds  of particulates  per  ton
                1 S2,3
of raw material.  '  '    Such installations are likely to be equipped only with
centrifugal  dust collectors.   The proposed standards would require  owners
and operators of new facilities to reduce the level of particulate
emissions to 99.3 percent below that of a very poorly controlled  kiln
and 99.7 percent below that of a very poorly controlled clinker cooler.
At many modern cement plants either electrostatic precipitators or
baghouses are used to collect dust from the kiln.  The kiln is the most
difficult item in a cement plant to control properly and thus is the
most likely to be controlled inadequately.   Baghouses, electrostatic
precipitators, and centrifugal collectors are used for control of the
other process equipment.  Baghouses are the most commonly employed
control devices for mills, conveyors, transfer points, storage silos,
etc.  Many of the dust collectors serve to recover product from exhaust
gas streams and to increase product yields.  Their function as air
pollution control devices may, therefore, be secondary.
Many state and local regulations, unlike the proposed standards, allow
particul ate emissions to vary with the rate of input of raw materials.
For a typical kiln-feed rate of 100 tons per hour, existing state and
local limits range from 0.32 to 0.90 pound per ton for kilns and from
0.19 to 0.64 pound per ton for clinker coolers, all of which are higher
than the proposed standards.  A few agencies have adopted stack-gas
concentration limits comparable to the proposed standards.  Because
some agencies use particulate sampling methods other than the EPA
method, the limits are not directly comparable.
                                                                             29

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JUSTIFICATION FOR PROPOSED STANDARDS

The proposed performance  standards  are based on inspections and stack
tests of existing facilities;  consultation with plant operators and
designers, control  equipment manufacturers, and state and local control
officials; and review of  the literature.  A principal literature source
was a government publication,  resulting from a cooperative study
conducted with representatives  of companies manufacturing port!and
cement, entitled Atmospheric Emissions from the Manufacture of Portland
Cement.

Preliminary investigations  revealed the locations of the 12 reportedly
best-controlled plants in the  United States.  No information obtained
indicated that foreign plants  were  using better technology than the United
States.  Consequently, no foreign plants were inspected.  Twelve United
States plants were visited  and information was obtained on the process
and control equipment; judgment was also made as to the feasibility of
conducting stack tests.   Five  locations were unsatisfactory because
control equipment was inadequate or the physical, layout of the equipment
made it impossible to conduct  tests (e.g., a pressure baghouse that does
not have a stack).   Stack tests were conducted at seven locations and
covered four kilns, three clinker coolers, and four raw-material and
finished-product mills.

Participate Matter from  Kilns and Clinker Coolers
Four kilns, as stated, were tested  by EPA; corroborative test data were
obtained from a local air pollution control agency on one of thefEPA
tested kilns.  Results of only three tests were available at the time
the standards were proposed.   Neither of the two wet-process kilns controlled
30

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with electrostatic precipitators  was  able to  meet  the  proposed  standards.
A test of a dry-process kiln controlled with  a  baghouse,  however,  showed
participate emissions of 0.20 pound per ton of  feed, which  is below the
proposed standard.  Inspections were  made of  three additional kilns
controlled with baghouses.   No visible emissions were  produced  from the
latter three kilns, although one  wet-process  kiln  showed  a  moisture-
condensation plume during cold weather.  These  kilns were not tested
because of the physical layout of the equipment.

Three clinker coolers were tested by EPA.  The  cooler  with  an electro-
static precipitator and one of the two units  with  baghouses were shown
to meet the proposed standard.  No visible emissions were observed from
two additional clinker coolers with baghouses,  although they were not
tested due to the physical  layout of the equipment.

Investigations confirmed that fabric-filter collectors can  be applied to
both kilns and clinker coolers in conventional  wet- and dry-process portland
cement production facilities to reduce particulate emissions to the limits
of the proposed standards.  It is possible that electrostatic precipitators
also can be used  to meet the proposed standard for kilns, but such precipi-
tators would have to be more efficient and probably larger than units presently
installed  in existing plants, since tests of the two kilns with electro-
static precipitators showed that neither was able to meet the proposed
standards.  No other particulate abatement schemes have  been demonstrated  to
be  capable of  achieving  the  standards,  although investigations  of  high-energy
scrubbing  are  under way.

 Particulate Matter from Other  Equipment

No emission standards  other than visible emission limits have been proposed

                                                                             31

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for other equipment in  cement  plants,  such as raw-material mill systems;
finished-product mill systems,  raw-material and finished-product storage
facilities, conveyors,  bagging  operations equipment, and bulk loading
and unloading facilities.   The  normal  industrial practice is to control
dust from these sources by  the  use  of  baghouses, although precipitators
sometimes are used on finish mills.  These devices prevent loss of material
from the process and reduce air pollution.  In most instances, the
economics of material recovery  are  sufficient to justify the abatement
devices without regard  to air  pollution  control regulations.  Inspections
by EPA engineers show that  no  visible  emissions occur from these devices
when they are properly  maintained:   Where visible emissions are encountered,
                                               4
they are likely to be  the result of bag  failure.

ECONOMIC IMPACT OF PROPOSED STANDARDS
It is estimated that three  new Portland  cement kilns and associated
equipment will be constructed  in the U.  S. each year and that three
existing systems will  be modified to the extent that they will come
under the proposed standards.

Many state and local agencies  presently  have regulations for cement
plants that require the same types  of dust-control equipment mandated
by the proposed standards.  These standards will not result, then, in
an appreciable increase in  the cost of a new cement plant.  The only
significant increase in cost would  be to a company that would otherwise
have constructed a poorly controlled plant in an area not covered by
adequate state or local regulations.  In any case, the installed
investment and operating costs of baghouse collectors and electro-
static precipitators cannot be attributed entirely to air pollution
control because many of the devices are  used for product recovery and
32

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are economically justifiable on that basis.   Thus,  investment costs
cannot be computed for air pollution control  alone.
The standard of performance for the kiln is sensitive to cost/benefit
analysis.  The standard is based on a baghouse collector; electrostatic
precipitators are alternative control devices.  The use of electrostatic
precipitators of efficiencies consistent with existing installations
would require that the standard be relaxed by a factor of 3 with a
saving of only about 1 percent of total  plant investment.  More
efficient precipitators could be installed, but the cost would be about
1.1 times that of baghouses.   The trend  in the cement industry is toward
the use of baghouse collectors, and this trend should be encouraged.
For a new wet-process plant with a capacity of 2.5 million barrels
per year (90 tons of feed per hour to the kiln), the total investment
for all installed air pollution control equipment will  represent
approximately 12 percent of the investment for the total  facility.
The cost of control equipment for the clinker cooler will be
approximately 10 percent of the cost of all air pollution equipment.
An electrostatic precipitator or baghouse for the kiln represents
approximately 60 percent of the cost of all air pollution equipment.
The remaining 30 percent of the costs will cover dust control for
the finished-product mill grinding system, conveyors, transfer points,
storage silos, etc.  Annual operating costs for the control equipment
will be approximately 7 percent of the total plant operating costs  if
a baghouse is used for the kiln, and 5 percent if an electrostatic
precipitator is used. '
                                                                              33

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For a new plant of 2.5 million barrels per year,  using the dry process,
the total installed investment cost of all  air pollution control  equipment
will be slightly higher than 13 percent of the total  facility investment
because additional control  equipment will  be required for the raw
material mill grinding system.   The operating costs  for dry-process  control
will be approximately the same as those for the wet process.
The impact of the proposed standards on control-equipment manufacturers
will be small.  Because the major manufacturers  of  control  equipment
offer a complete line (electrostatic precipitators,  baghouses,  and
scrubbers), the possible reduction in sales of electrostatic precipitators
will have little economic impact on manufacturers because the sale  of
baghouses will increase.

REFERENCES

1.  Kreichelt, T.  E., D.  A. Kemnitz, and S.  T. Cuffe.   Atmospheric
    Emissions  from the Manufacture of Portland Cement.   U.S. DHEW,  PHS.
    National  Center for Air Pollution Control.   Cincinnati,  Ohio.
    PHS Publication No. 999-AP-17.  47 p.
2.  McGraw, M. J.  and R.  L. Duprey.  Compilation of  Air Pollutant Emissions
    Factors.   Preliminary Document.  Environmental  Protection Agency.
    Research  Triangle P ark, N.  C.  April  1971.
3.  Guidelines for Control  of Emissions from Cement  Plants.  Internal
    Document.   Environmental Protection Agency.  Raleigh, N. C.  1970.
4.  Personal  communication from  R. E. Frey,  Vice President,  Mikro Pul,
    Summit, N. J.   June 4, 1971.
5.  Eli as, Jv.R. and J. M.  Dement.  The Financial Impact of Air Pollution
34

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    Control  Upon the Cement Industry.   Internal  Document.  Environmental
    Protection Agency.    Raleigh,  N.  C.   February  1971.
6.  Personal  communication from D.  Stinner,  Design Engineer,  Fuller  Company,
    Catasauqua, Pa.   July 9,  1971.
                                                                             35

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                   TECHNICAL  REPORT NO.  4  -
                        NITRIC ACID PLANTS

SUMMARY OF PROPOSED STANDARDS
Standards  of performance are being proposed for new facilities producing
so-called  "weak nitric acid" (defined as 50 to 70  percent strength).   The
standards  will not apply to the various processes  used to produce strong
acid by extraction or evaporation of weak acid, or by the direct strong-
acid process.
The standards of performance are being proposed for total oxides of
nitrogen and for attendant visible emissions, which are a function of
nitrogen dioxide concentration.
The standards would limit emissions to the atmosphere as follows:

     1.   No more than 3.0 pounds of nitrogen oxides (NOX) per ton
         of acid produced or 1.5 kilograms NO  per metric ton,
                                           J\
         averaged over a 2-hour period.  Acid produced is expressed
         in tons of equivalent 100-percent-strength nitric acid.

     2.   Visible air pollutants shall not be released to the atmosphere.

For a typical weak-nitric acid production facility, the standard of 3.0
pounds per ton of acid is equivalent to an undiluted stack-gas concentra-
tion of 209 parts per million (ppm) by volume.  This assumes an exhaust
volume of 122,000 standard cubic feet  (scf) per ton of acid produced.
           i
                                        37

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EMISSIONS FROM  NITRIC ACID PLANTS



Without control  equipment, nitric  acid  production  facilities will


release about 43 pounds of NOX per ton  of acid  produced  at  a concen-


tration of about 3000 ppm NOX (by  volume) in the exit gas stream.


Approximately 50 percent of this emission will  be  in  the form  of


nitrogen dioxide (N02)> an opaque  reddish-brown gas;  the remainder will


be colorless nitric oxide (NO).  The  standards  would  require owners


and operators of new facilities to reduce NOX emissions  to  a level 93


percent below the emissions produced  by an uncontrolled  facility.



Of the existing 194 weak-nitric acid  production facilities  operated


by government and commercial  operators  .in the United  States in 1971,


only 10 were specifically designed to include NOX  abatement, which is


accomplished by means of decomposition  of NOX to elemental  nitrogen and


oxygen.  An additional  52 plants,  however, were designed to use catalytic


combustion devices for decolorization and, subsequently, heat  recovery.


The so-called "decolorizers"  convert  visible N02 to colorless  NO with


the concurrent generation of  appreciable heat.  -Energy recovered from


the exhaust gases is used primarily to  power the air-compressor turbine


in the acid process.



There are no state or local NO  emission regulations  in  the United States
                              A

that apply specifically to nitric  acid  production.  Ventura County,


California, has enacted a limitation  of 250 ppm NO that governs nitric
                                                  /\
                                                         2
acid plants as well as steam  generators and other  sources.




Visible-emission regulations  with  equivalent opacity  provisions also


restrict nitric acid manufacturing operations in many areas.   Never-*


theless, operators can meet these  requirements  through the  use of



33

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decolorizer devices, which have little  effect  on  total NOX emissions.

JUSTIFICATION OF PROPOSED STANDARDS
The proposed performance  standards  are  based on inspections and stack
tests of existing  facilities;  consultations with  operators, designers,
and state and local  control  officials,  and review of the literature.

In 1962, a cooperative project was  initiated by the Manufacturing
Chemists' Association  and the  U.S.  Public Health  Service to study
emissions from selected chemical  manufacturing processes.  A goal of
that program was  to  publish  relevant  information  in a form helpful to
control  agencies  and to the  chemical  industry.  The results of the
study were subsequently published as  Atmospheric  Emissions from
Nitric Acid Manufacturing Processes.

Investigations of current nitric  acid control  technology by EPA engineers
showed that catalytic  decomposition systems can be applied to conventional
nitric acid production facilities to  reduce NOX emissions to levels within
the limits of the  proposed standard.  Although alternate techniques are
under development, no  other  NOX abatement schemes have been demonstrated
capable of achieving the  standard.

The catalytic systems  are installed downstream of the absorption  tower
at conventional acid-production facilities utilizing the ammonia-
oxidation process.  Natural  gas or  hydrogen-rich  fuel is burned in the
gas stream to raise  the temperature and to remove excess oxygen prior
to catalysis.  Nitrogen oxides are  destroyed in a stepwise process.   Initially,
N02 is converted  to  NO; then the  NO is  decomposed to nitrogen and oxygen.
The reactions are  exothermic,  and reaction products leave the system
at temperatures as high as 1500°F.  Operators  recover heat from the
                                                                            39

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tail gases.





A survey of the ten plants in the United States that are equipped with



these systems indicated that five were consistently achieving low NOX



emission levels.  Testing and inspection confirmed that three of the plants



could be operated well within the performance standard.  The other two were



found to exceed the standard during EPA tests; their emissions were 4.8 and



8.4 pounds of NOX per ton of acid produced.  Both were found to be operating



with partially deactivated catalyst.  Company tests using accepted test



procedures indicated that one of the facilities had been achieving an



average of 2.0 pounds NOX per ton of acid a few months prior to the test.



At each installation, testing was conducted for about 6 hours on each of



3 consecutive days.





Two of the three facilities found to meet the standard burned hydrogen-



rich purge gas from an adjacent ammonium nitrate plant.  The third plant



.burned natural gas.  During the EPA tests, NOY emissions from each of
                                             ^\


the three  facilities were consistently lower than the maximum levels of



the performance standards.  Measurements were conducted with continuous-



NO -monitoring devices, and values were confirmed by the phenoldisulfonic
  A


acid method specified in the regulation.







The nitric acid production facilities on which the tests were conducted



were of the conventional ammonia-oxidation type of design.  They ranged



in  size from  55 to 350 tons per day (24-hour).





All five of the facilities with catalytic abatement devices were found



to  operate with no visible emissions, which indicated that even the two



systems with  partially spent catalyst were serving as effective decolorizers,



Although no separate N02 analyses were performed, it appears that most of





40

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the NC>2 was converted to colorless  NO.   Thus,  any  facility meeting the
mass NOX limit will produce no visible  emissions from  the stack.

ECONOMIC IMPACT OF PROPOSED STANDARDS

Based on projections made by nitric  acid plant builders and operators, it is
estimated that construction of new  plants will average five facilities per year.

In considering costs for NOX control, the assumption was made that any new
nitric acid facility would be equipped  with a  catalytic decomposition system
for heat recovery and possible NOX  abatement even  if NOX limits were not
imposed.  In the absence of any regulation on  NOX  emissions, this unit would
be operated as a decolorizer and would  produce the heat recovery needed to
drive a process-air compressor.   Abatement of  NOX  requires that all oxygen
be burned from the tail-gas stream;  this is not a  requirement for heat
recovery.  Consequently, the fuel used  for decolorization and partial abate-
ment is less that that  necessary for meeting the proposed standards.
Furthermore, typical catalysts will  become inactive for NOX abatement
purposes long before they lose their ability to decolorize.

The standard of performance represents  full control and is insensitive
to cost/benefit analysis.   The alternative is essentially no control.  The
standard of performance  does not represent a significant increase in the
capital cost for a new  plant, although  operating costs will increase as
the result of increased  fuel use and decreased  catalyst life.

Estimates of both capital  investment and operating costs for catalytic
decomposition systems vary widely because of differences in
design philosophy and choices of heat and power recovery among different
construction firms.  Also,  reported  catalyst life varies from several

                                                                            41

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months to several  years.   Cost estimates  for a  modern  plant with  a  capacity
of 300 tons per day show that full  control  adds 1  percent  to  the  cost
of the most typical product,  ammonium nitrate,  and represents 4 to  8
percent of the total  capital  investment for the facility.

REFERENCES
1.  Private communication from Joseph Povey, Product Specialist,
    Matthey Bishop, Inc., Philadelphia, Pa.   July  8, 1971.

2.  Rule No.  59, Rules and Regulations.  Air Pollution Control District,
    County of Ventura, California.
3.  Gerstle,  R. W. and R. F.  Peterson,  Atmospheric Emissions  from
    Nitric Acid Manufacturing Processes.  U.S.  DHEW, PHS.  Division  of
    Air Pollution.  Cincinnati, Ohio.   PHS  Publication Number 999-AP-27.
    1966.  89p.
42

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                  TECHNICAL REPORT  NO.  5  -


                     SULFURIC  ACID  PLANTS




SUMMARY  OF PROPOSED STANDARDS



Standards of performance are being  proposed for new contact-process  sulfuric


acid and oleum facilities that burn elemental  sulfur, alkylation acid,


hydrogen sulfide,  organic sulfides, mercaptans, or acid sludge.   They


do not  apply to metallurgical  plants that use acid plants as SC>2 control


systems, or  to chamber process plants or acid concentrators.
                                                          i


The proposed standards establish limitations on sulfur dioxide and  acid


mist emissions, and attendant visible emissions.



The emission limitations being proposed are summarized as follows:



Sulfur  Dioxide



    No  more  than 4.0 pounds of sulfur dioxide  ($02)  per ton of acid


    (100 percent H^SO.) produced or 2.0 kilograms S02 per metric ton.



Acid Mist



    1.  No more than 0.15 pound of acid mist  (measured as ^SO*) per ton


       of acid (100 percent H-SOJ produced or 0.075 kilogram acid mist


       per  metric ton.



    2.  No visible air pollutants shall be  released  to the  atmosphere.



                                       43

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The standard allows about 0.3 percent of the feedstock sulfur to
be released to the atmosphere as  SO,,.   For  a typical  plant,  the  sulfur
dioxide standard is equivalent to an exit-gas concentration  of 280  ppm.
Where rich S02 streams (greater than 8.0 percent)  are processed, the
equivalent concentration will be  greater than 280  ppm.   Conversely,
where weak SOp streams are handled,  permissible  concentrations will be
lower and more restrictive.   The  range 180  to 350  ppm will cover emissions
from most contact acid plants.

The acid mist standard of 0.15 pound per ton of  acid  is  equivalent  to
a concentration of 0.8 rug of sulfuric acid  per standard  cubic foot
of.effluent for a typical sulfur-burning system.   Volumetric equivalent
concentrations in milligrams per  standard cubic  foot  (mg/scf) will  vary
from plant to plant because  they  are dependent on  the inlet  sulfur  dioxide
concentration.

EMISSIONS FROM SULFURIC ACID  PLANTS
Almost all existing domestic contact-process sulfuric acid plants are
of the single-absorption design and  have no sulfur dioxide emission
controls.  Emissions from these plants range from  1500 to 6000 ppm  SO-
by volume, or 21.5 to 85 pounds of S02 per  ton of  acid produced.  Several
state and local agencies limit SOp emissions to  500 ppm  from new sulfuric
acid plants, but few such facilities have been put into  operation.

Many sulfuric acid plants utilize some type of acid mist control device,
but a significant number have no  controls whatever.   Uncontrolled acid
mist emissions vary between  2 and 50 milligrams  per standard cubic
foot (mg/scf), or 0.4 to 9 pounds of HpSO.  per ton of acid produced.

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The lower figure represents  emissions  from  a  plant burning high-purity
sulfur.   State and local  regulatory  agencies  have only  recently made
limits on acid mist emissions more stringent; some agencies,  for  example,
have adopted limits of 1  and 2 mg/scf, respectively,  for new  and  existing
plants.

JUSTIFICATION OF PROPOSED STANDARDS

The proposed performance standard for S02 is  based on inspections and
stack tests of existing facilities; consultations with  operators,
designers, and state and local control officials;  and review  of the
literature.  Appreciable information concerning existing single-absorption
plants was derived from a cooperative study initiated in 1962 by  the
Manufacturing Chemists' Association, Inc.,  and one of EPA's predecessor
organizations, the National  Air Pollution Control Administration.  Results
of the   study were published in a Public Health Service document, Atmospheric
Emissions from Sulfuric Acid Manufacturing  Processes.

Much reliance necessarily had to be placed  on the  two demonstrated SC>
removal  processes and on the single domestic  application of each  process
to full-scale acid production facilities.  Tests of  the two plants for
both acid mist and SCL emissions were conducted in  1971 by EPA personnel,
using test methods presented in the regulations.

Sulfur Dioxide
The two  plants tested and evaluated by EPA engineers  were:  (1)  a plant
of typical dual-absorption design and (2) a conventional single-absorption
spent-acid-burning plant that uses a sodium sulfite-bisulfite  scrubbing
process  to recover SCL from tail gas.  The dual-absorption plant keeps
                                                                             45

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SOp emissions low by converting more of the feedstock sulfur to sulfuric
acid.   Other processes in use can control  SCL to the levels  set by the
proposed standards; however, they are considered suitable for special
situations only since they produce either a weak acid or a by-product
that has limited marketability.

Over 20 dual-absorption plants that have been operating success-
fully in Europe for several  years use both elemental  sulfur  and roaster
gas as feed.  The literature reveals that three of these plants produce
maximum emissions ranging from 1.2 to 3.1  pounds of SO,, per  ton of acid
produced, or 91 to 260 ppm SOp by volume.

The first U. S. dual-absorption plant was put into operation in 1970
and has been in continuous operation since then.  Stack tests conducted
by both EPA and company personnel show that SOp emissions normally do
not exceed the limits of the performance standards.  During  EPA tests,
the facility was being operated at only 52 percent of rated  production
and S02 emissions were correspondingly lower than normal, ranging from
1.5 to 1.9 pounds per ton of acid produced.  These values were corroborated
by company tests.  Testing by the operator showed full-load  SOp emissions
to be consistently less than 4.0 pounds of SOp per ton of acid, with
emissions below 3.0 pounds per ton much of the time.

It has been demonstrated that sulfur dioxide can be removed  from tail
gases of single-stage acid plants by means of a sodium sulfite-bisulfite
scrubbing process.  In this system, SOp is thermally recovered from the
scrubbing solution and fed back to the acid-manufacturing process.  The
only full-scale sulfite-bisulfite system was installed on an existing
spent-acid plant in 1970.  Since January of 1971, it has been in continuous
46

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operation.   Tests of this plant by EPA personnel  have shown emissions
of 2.6 to 2.9 pounds of SCL per ton of acid produced.  The tests represent
some 18 hours of testing over a 3-day period.   Similar tests conducted
by company personnel indicate that the plant is capable of sustained
operation at this level of SC   collection.
Sulfite-bisulfite scrubbing processes produce waste liquor that contains
sodium sulfate and sodium thiosulfate.  Methods for disposing of these
products will have to be considered by plant operators.   The process
designers are investigating several means of handling these wastes.
Continuous stack monitoring at the plants tested indicates that at full
load the plant can be consistently operated so that emissions are kept
within the limits of the performance standard.  Emissions exceed these
values only during abnormal operation, and on these occasions the values
are seldom more than 6.5 pounds of SCL per ton of acid produced, or about
500 ppm.  As operators obtain more experience with these systems,
abnormal operating conditions are expected to occur less frequently.
Acid Mist
Review  of  the  literature and  investigations by EPA engineers showed that
many existing  plants  have already  installed high-efficiency acid-mist
eliminators, including  both fiber  demisters and wire and tube electro-
static  precipitato.rs.   Fiber  demisters are more commonly employed in
the  industry.

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The standard for new sources is based principally on stack tests con-
ducted at the two plants that use sulfur dioxide control  systems.   EPA
tests of the dual-absorption plant and the plant using the sulfite
scrubber system show that acid-mist emissions can be held below the
standard.  The lowest levels, 0.02 pound per ton of acid produced,
were recorded at the dual-absorption plant during periods when the
plant was operating at about one-half load.  At other times, the acid
mist emissions from the two plants ranged from 0.04 to 0.15 pound per
ton of acid produced.

It must be emphasized that the acid mist standard is based on results
obtained with the EPA method published in the regulations.  Measurements
with other test methods may give greater or lesser values, depending on
whether the method measures sulfur trioxide (SO-,) and acid vapor.   (The
latter two materials are sometimes considered under the collective
term "acid mist.") Acid vapor and S03 are converted to acid mist on
cooling and/or moisture absorption.

Inasmuch as new plants will be required to install either the dual-
absorption process or a tail-gas scrubbing system, it would appear
that emissions from the plants tested are representative of emissions
from new plants.  It is uncertain whether the dual absorption or the
sulfite scrubbing process inherently reduces acid mist levels below those
that would normally be encountered from a single-absorption plant.  In
any case, the literature indicates that both high-efficiency fiber
demisters and electrostatic precipitators can reduce acid mist emissions
                                       2
to 0.10 pound per ton of acid produced.   The most severe conditions
possibly are encountered at spent-acid plants that process oleum (fuming
43

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sulfuric acid).   The best-controlled  plants of  this type produce no
visible emissions.

ECONOMIC IMPACT OF PROPOSED  STANDARDS
It is estimated that over the next  few years  two new sulfuric acid plants
will be constructed annually in  the United States.

Sulfur dioxide control  systems represent  a significantly greater capital
investment than acid mist collectors.  Nevertheless, SOp control systems
provide a dividend to the operator  in the form  of increased acid yields.
Elevated sulfur costs provided part of the  incentive  for the  development  of
the  dual-absorption process.  The economics  of high-yield  processes  such
as dual absorption and sulfite scrubbing will continue to  be  dependent  on
the  price of sulfur, with higher prices  favoring greater S02  control.

The  standard of performance for  sulfur dioxide is  insensitive to cost/..
benefit analysis because no other control systems are  available.  The
alternative would be a single-stage plant with  no S02  control.

The  costs of control vary with location.  Nevertheless, new plants would
be expected to use the dual-absorption  process, whereas modified existing
plants would probably use an  SC^-scrubbing  system,  such as the  sulfite-
bisulfite process.  A dual-absorption plant with a 700- to 750-ton-per-
day  capacity may cost 22 percent more than  an uncontrolled single-absorption
plant; however, the operating costs are  essentially the same.  Full  control
adds 3 to 5 percent to the  cost of sulfuric acid,  not including return  on
investment.

A new single-absorption  plant, of the same  capacity,  with a sodium
sulfite-bisulfite  scrubbing  process attached may cost 35 percent

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more than an uncontrolled plant.   The S02-control  cost  is  about
5.5 percent of the sulfuric acid  list price,  without return  on
investment.

Acid mist control equipment is relatively less  costly,  representing
from 1 to 2 percent of the capital  investment of a 700- to 750-ton-
per-day plant.  The additional operating costs,  including  amortization,
represent 0.1 to 0.7 percent of the current sulfuric acid  list  price,
depending on the type of control  equipment used.   Again, return  on
investment is not included.

REFERENCES

1.  Atmospheric Emissions from Sulfuric Acid Manufacturing Processes.
    Cooperative Study Project:Manufacturing Chemists'  Association,  Inc.,
    and Public Health Service.  U.S.  DHEW, PHS.  Division  of Air Pollution.
    Cincinnati, Ohio.  PHS Publication No. 999-AP-13.   1965.   127 p.

2.  Chemico Construction Corporation.  Engineering Analysis  of Emissions
    Control Technology for Sulfuric Acid Manufacturing Processes.  Final
    Report under Contract No. CPA 22-69-81, Public Health  Service.   U.S.
    DHEW, PHS.  National Air Pollution Control  Administration.   Durham,
    N.C.  Publication No. PB-190-393.  March 1970.

3.  Economic evaluation is based on process and equipment  costs  obtained
    from manufacturers of various sulfur dioxide and acid  mist control
    equipment, from sulfuric acid plant operators, and from Reference  2.
50

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