United States	Industrial Environmental Research EPA-600/7-78-164a
Environmental Protection Laboratory	August 1978
Agency	Research Triangle Park NC 27711
Environmental
Assessment of Coal-
and Oil-firing
in a Controlled
Industrial Boiler;
Volume I. Executive
Summary
i
f
4
Interagency
Energy/Environment
R&D Program Report

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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1.	Environmental Health Effects Research
2.	Environmental Protection Technology
3.	Ecological Research
4.	Environmental Monitoring
5.	Socioeconomic Environmental Studies
6.	Scientific and Technical Assessment Reports (STAR)
7.	Interagency Energy-Environment Research and Development
8.	"Special" Reports
9.	Miscellaneous Reports
This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
RESEARCH AND DEVELOPMENT series. Reports in this series result from the
effort funded under the 17-agency Federal Energy/Environment Research and
Development Program. These studies relate to EPA's mission to protect the public
health and welfare from adverse effects of pollutants associated with energy sys-
tems. The goal of the Program is to assure the rapid development of domestic
energy supplies in an environmentally-compatible manner by providing the nec-
essary environmental data and control technology. Investigations include analy-
ses of the transport of energy-related pollutants and their health and ecological
effects; assessments of, and development of, control technologies for energy
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This report has been reviewed by the participating Federal Agencies, and approved
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This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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EPA-600/7-78-164a
August 1978
Environmental Assessment of Coal-
and Oil-firing in a Controlled
Industrial Boiler;
Volume I. Executive Summary
by
C. Leawitt, K. Arledge, C. Shih,
R. Orsini, W. Hamersma, R. Maddalone,
R. Beimer, G. Richard, and M. Yamada
TRW, Inc.
One Space Park
Redondo Beach, California 90278
Contract No. 68-02-2613
Task No. 8
Program Element No. EHE624A
EPA Project Officer: Wade H. Ponder
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460

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DISCLAIMER
This report has been reviewed by the Industrial Environmental
Research Laboratory, U. S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents necessarily
reflect the views and policies of the U. S. Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
ii

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ABSTRACT
The report gives results of a comparative multimedia assessment of
coal versus oil firing in a controlled industrial boiler. Relative
environmental, energy, economic, and societal impacts were identified.
Comprehensive sampling and analyses of gaseous, liquid, and solid emis-
sions from the boiler and its control equipment were conducted to identify
criteria pollutants and other species. Major conclusions include: (1)
While the quantity of particulates from oil firing is considerably less
than from coal firing, the particles are generally smaller and more
difficult to remove, and the concentration of particulates in the treated
flue gas from oil firing exceeded that from coal firing. (2) NO and CO
A
emissions during coal firing were about triple those during oil firing.
(3) Sulfate emissions from the boiler during coal firing were about
triple those during oil firing; however, at the outlet of the control
equipment, sulfate concentrations were essentially identical. (4) Most
trace element emissions (except vanadium, cadmium, lead, cobalt, nickel,
and copper) were higher during coal firing. (5) Oil firing produces
cadmium burdens in vegetation approaching levels which are injurious to
man; coal firing may produce molybdenum levels which are injurious to
cattle. (6) The assessment generally supports the national energy plan for
Increased use of coal by projecting that the environmental insult from
controlled coal firing is not significantly different from that from oil
firing.
This report was submitted in fulfillment of Contract Number 68-02-2613,
Task 8 by TRW Environmental Engineering Division under the sponsorship of
the U.S. Environmental Protection Agency. This report covers a period from
October 24, 1977 to May 5, 1978, and work was completed as of May 5, 1978.
iii

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LIST OF ABBREVIATIONS
acm/min -
- Actual Cubic Meters Per Minute

ACFM
- Actual Cubic Feet Per Minute

DSCM
- Dry Standard Cubic Meters

ESCA
- Electron Spectroscopy for Chemical
Analyses
FGD
- Flue Gas Desulfurization

ICPOES -
- Inductively Coupled Plasma Optical
Emission Spectroscopy
MATE
- Minimum Acute Toxicity Effluent

NAAQS
- National Ambient Air Quality Standards
NSPS
- New Source Performance Standards

SSMS
- Spark Source Mass Spectrometry

TSP
- Total Suspended Particulate

iv

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ACKNOWLEDGMENTS
The cooperation of the Firestone Tire and Rubber Company and FMC
is gratefully acknowledged. We are particularly indebted to Gary Wamsley
of Firestone and Carl Legatski of FMC, without whose cooperation this
assessment could not have been completed.
v

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EXECUTIVE SUMMARY
The industrial nations of the world are being forced to simul-
taneously deal with two very difficult and contradictory problems. The
relatively cheap and convenient sources of energy are rapidly being
depleted while the need for increasingly stringent control of pollution is
making the environmentally acceptable use of the energy sources that are
available more difficult. One response to these dual needs has been to
use the more abundant high polluting fuels in combustion systems that have
sophisticated pollution controls. The technologies that are used to
control pollution are new relative to combustion technology. Therefore,
the subtle short- and long-term effects of these new technologies are not
yet completely known.
The objective of this program is to conduct a comparative, multi-
media environmental assessment of oil vs. coal firing in controlled
industrial and utility boilers and to draw conclusions about the compara-
tive environmental, energy, and societal impacts of firing oil versus firing
coal. A secondary objective of this program is to recommend the approach
to be used for subsequent assessments of a variety of combustion related
pollution sources.
INTRODUCTION
This report presents the comparative assessment of controlled Indus-
trial boilers. The major technical input for this assessment was feed stream
and emissions characterization data collected as part of the Conventional
Combustion Emission Assessment Program. These data were derived from
rigorous sampling and analysis and specify the types and quantities of
all solid, liquid, and gaseous pollutant species of interest in each of the
inlet and outlet streams of a controlled oil- and coal-fired industrial
boiler. A comprehensive assessment of each fuel type in the controlled
industrial boiler was accomplished to determine:
•	The types and amounts of pollutants that are released during coal
and oil combustion 1n an uncontrolled boiler:
•	The types and amounts of pollutants that are released during the
combustion of each fuel in a controlled boiler;
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•	The effectiveness of the controls with respect to each
controlled pollutant;
•	If the control devices modify pollutants that pass through
the controls;
•	If the controls themselves create pollutants.
The comprehensive assessment results for the oil and coal-fired
industrial boiler were then used in a comparative emission assessment
to determine the differences in the types and quantities of all pollutant
species of interest.
The results of the industrial comparative emission assessments were
then evaluated to determine what conclusions could be drawn about the oil
versus coal firing. The comparative impacts identified were summarized by
environmental, energy, economic, and societal cateqories.
This report is organized in three volumes. Volume I is the Executive
Summary. The comparative assessment of emissions and their impacts is
presented in Volume II. Volume III describes the test site, the sampling
and analysis activities; presents the comprehensive assessments of coal and
oil firing; and provides the appendices which contain detailed test and
analysis results.
There are a number of significant differences in the quantities,
characteristics, and impacts of the emissions resulting from coal and oil
firing in a controlled industrial boiler. In the following paragraphs the
most important of these differences are summarized. It should be kept in
mind, however, that the conclusions are based on tests conducted on only
one Industrial boiler, one type of coal, and one type of oil. It should
not be assumed that these conclusions apply to all industrial boilers under
all circumstances. The results of this program should, perhaps, best be
thought of as a good indication of the impact differences between coal
and oil firing and as a set of guidelines on which future work can be
based.
TEST AND ANALYSIS
The test unit used for this assessment is a dual fuel industrial pro-
cess steam boiler operated by the Firestone Tire and Rubber Company in
Pottstown, Pennsylvania. The 10 megawatt equivalent boiler 1s equipped
2

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with a pilot FMC, Inc. flue gas desulfurization (FGD) unit that is
designed to treat approximately one-third of the flue gas produced by
the boiler when it is operating at full load (3 megawatt equivalent).
The boiler was originally designed to burn coal but was later modified
to burn either high volatile eastern bituminous coal or Number 6 fuel oil.
Table 1 presents a list of the major boiler parameters. The boiler has no
N0X controls.
The boiler produces four liquid waste streams: boiler feed water
pretreatment waste, steam drum blowdown, mud drum blowdown and cooling
water. All liquid waste streams except the cooling water are mixed with
process waste water from elsewhere in the plant. This combined stream is
then pumped directly into the municipal sewerage system. The boiler
cooling water is pumped directly into the municipal sewerage system
without mixing with other plant waste streams.
TABLE 1. SUMMARY OF BOILER PARAMETERS
Manufacturer:
Type of burner:
Number of burners:
Boiler type:
Oil/pulverized coal ;
face fired;
integral furnace;
dry bottom
Babcock and Wilcox, Type P-22 EL
Circular conical
3
Burner arrangement: Triangular, one face
Air preheater:
Fuel :
Number of 6 fuel oil;
High volatile bituminous coal,
Class II, Group 2, of ASTM D388
Yes
Design steam rate: 45,000 kg/hr 000,000 lb/hr);
Use:
Process steam
3

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The pilot FGD unit 1s a double alkali scrubber that produces only a
solid cake as a waste product. The scrubber does not produce a liquid
waste stream. It is designed as a sulfur dioxide (SO2) and particulate
control device, and will operate on either fuel without modification.
Test and Analysis Summary
Sampling and analysis of gaseous, liquid, and solid pollutants were
conducted according to the EPA Level 1/Level 2 criteria, except that both
Level 1 and Level 2 sampling were conducted simultaneously because of pro-
gram time constraints. Level 1/Level 2 analysis procedures were followed
except Level 2 analysis was conducted prior to receiving the results of
Level 1 analysis in those cases where sample degradation was anticipated.
Figure 2 shows the sampling locations. Table 2 summarizes the samples
taken and analyses conducted.
SCRUBBER
FEED
SOLIDS
EXHAUST
GAS TO STACK
EXHAUST GAS
TO STACK
EXHAUST
GAS

SfeL
SCRUBBER
MAI
WATER
FGD
CAKE

LANDFILL

KEUP ^
MULTICLONES
FE6DWATER
FROM
PRETREATMENT
UNIT ~
TO MUNICIPAL
SEWAGE
TREATMENT
FLY ASH
fly ash
STORAGE
EXHAUST
GAS
STEAM
COAL
BOILER
tf GFND
1	- FUEL
2	- BLOWDOWN
3	- FLYASl
A - EXHAUST GAS
FGD INLET
EXHAUST GAS
FGD OUTLET
6	- SCRUBBER CAKE
7	- MAKE UPWATER
8	- SCRUBBER F6EO SOUGS
Figure 2. Diagram of boiler and flue gas desulfurlzatlon
system showing sampling locations.
4

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TABLE 2. PARAMETERS SAMPLED FOR COAL AND OIL FIRING
Location
Parameter
Sampling Method	Analysis
1
FUEL (coal & oil)
C, H, N, S, ash,
moisture,
heating value
Inorganics
Grab
Ultimate (lab)
Level II (lab)
48.5
COMBINED BLOWDOWN
Alkalinity/acidity
pH
conductivity
hardness
TSS
nitrate
sulfate
sul fite
phosphate
aimionla
nitrogen
organics
FLYASH
inorganics
organics
FLUE GAS (inlet & outl
CO
XO,
N0/N05/N0
Ng.Ojj* X
S02
so?/so,
h2so.,hci. hf,
particulate sulfate,
total hydrocarbons
(as CH )
Cj - Cg organics
particulate & vapor
particulate sizing
Composite dipper On-site HACH kit
SCRUBBER CAKE
inorganics
organics
Composite grab
et)
Continuous, Beckman
Model 865
Grab (bag)
Grab (bag)
Continuous, TECO
Model 10A
Grab (bag)
Continuous, TECO
Model 41
Goksoyr-Ross
Continuous, Beckman
Model 400
Grab (bag)
SASS
Method 5
Anderson impactor
SASS
Composite grab
Level 1 & 2 (lab)
Level 1 & 2 (lab)
Level 1 & 2 (lab)
Direct reading
GC (TCD) on site
GC (TCD) on site
Direct reading
GC (TCD) on site
Direct reading
Level 2 (lab)
Direct reading
GC (FID) on site
Level 1 (lab)
Level 2 (lab)
Level 1
Level 2
Level 1 & 2 (lab)
Level 1 & 2 (lab)
BOILER & SCRUBBER
MAKEUP WATER
organics
Inorganics
SCRUBBER MAKEUP
SOLIDS
Top grab
Grab
Level 1 (lab)
Not requi red
Not requi red
5

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EMISSIONS
Table 3 summarizes the annual emissions resulting from coal and
oil firing. The table presents estimates of air emissions both before
(inlet) and after (outlet) the scrubber. Liquid effluent and solid
waste rates are presented for both the controlled and uncontrolled cases.
Outlet emissions were determined on the basis of 100 percent of the
flue gas being treated by the scrubber. It was assumed that additional
scrubber modules, identical to the existing one, could be added such that
all of the flue gas was processed in exactly the same manner as the fraction
that actually passed through the scrubber. In this way, emissions from the
pilot scrubber could be scaled up to represent the total flue gas flow. All
emissions data and conclusions are based on this assumption.
COMPREHENSIVE ASSESSMENT OF COAL FIRING
Criteria Pollutants
Uncontrolled emissions of criteria pollutants generally corresponded
well with values reported in AP-42. Although N0X emissions were slightly
higher than the average AP-42 value, they appear to be within the normal
range for similar Industrial units.
N0X reductions varying from approximately 0 to 24 percent were mea^
sured across the scrubber. However, the magnitude of NO* reductions could
not be correlated to changes in variables monitored during the test
period (I.e., temperature, gas flow rate, liquid/gas ratio, boiler load,
etc.). For this reason, it is considered feasible that observed N0X
reductions are a sampling phenomenon, perhaps related to leaks in the
sample train.
Sulfur dioxide removal data Indicated an average scrubber efficiency
of 97 percent. Controlled SOg emissions were 36.3 ng/J (0.08 pounds/MM
Btu) which 1s less than either existing or proposed NSPS limitations for
utility boilers.
6

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TABLE 3. ANNUAL EMISSIONS





kg/year





Scrubber Inlet


Scrubber Outlet



Coal Firing
Oil Firing
Coal/Oil
Coal Firing
Oil Firing
Coal/Oil
Gaseous
NOx (as NO2)
500,810
164,230
3.05
442,520
157,390
2.81

S02
1 ,127,300
906,202
1.24
36,800
24,453
1.51

S03
6,184
7,249
0.85
4,157
5,183
0.80

S04*
67,214
20,894
3.22
8,110
8,303
0.98

CO
16,119
4,991
3.23
14,497
4,845
2.99

Organics (as CH4)
5,870
2,272
2.58
6,377
2,500
2.55

Cl - c6+
<5,606
<4,164
--
<5,606
<4,164
—

C7 - Cl 6
345
155
2.22
274
18
15.2

C16+
2,311
2,381
0.97
335
392
0.85

Total Particulates
2,991 ,700
53,832
55.6
18,856
13,686
1.38

<1„
—
--
—
11 ,691
11,359
1.03

1 - 3p
—
—
—
5,657
1,642
3.45

3 - 10„
—
—
—
1,320
634
1.93

=>10p
—
—
—
188
0*
—
m3/year
Liquid
Blowdown/Waste Water
^76,000
-v 76,000
Ĥv 1
•v. 76,000
-*.76,000
% 1

Cooling Uater
-*-86,000
-V. 86,000
-*. 1
86,000
t86,000
<*, 1
Solid
Bottom Ash
^ 778,600
% 7,600
-v. 103
•v, 778,600
Ğ>. 7,600
Ĥ*-103

Fly Ash
-v-1 ,800,000
15,000
Ĥv 120
•vl ,800,000
*15,000
•*.120

Scrubber Cake
0
0
—
8,054,100
3,011,000
2.67
^Assuming 100% load, 45 weeks per year (7,560 hrs/year).
These values represent the detection Unit of the Instrument used.
These values represent oil firing particulate with a niniw* of coal ash contanination.

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Mass balance data indicate that the multiclone unit upstream of the
scrubber was removing little or no fly ash during the test period. The
scrubber was found to remove 99.4 percent of the inlet particulate.
Inorganics
Although the removal efficiency for total particulates is high, there
appears to be a net increase 1n emission rates across the scrubber for
particulates less than 3 nm in size. This net increase can be attributed
to the poor removal efficiency of the scrubber for fine particulates, and
to the sodium bisulfate (NaHSO/j) and calcium sulfite hemihydrate (CaS03'
1/2^0) particulates generated by the scrubber. Both NaHS04 and
CaS03*l/2H20 have been identified at the scrubber outlet but not at the
inlet.
The relatively poor removal efficiency (approximately 30%) for S03
across the scrubber is an indication that S03 1s either present as very
fine aerosols 1n the scrubber Inlet, or 1s converted to very fine aerosols
as the flue gas stream is rapidly cooled inside the scrubber.
Analysis has shown that while there may be higher surface con-
centrations of sulfur-conta1n1ng compounds 1n the particulates emitted
from the scrubber, most of the sulfur-containing compounds are probably
present as solid sulfates and sulfites. Thus, 1t 1s conceivable that
sulfuric acid vapor 1s condensed and deposited on the particulates emitted,
whereas sodium bisulfate and calcium sulfite hemihydrate are emitted as
fine, solid particulates.
The overall sulfur balance Indicates that over 92 percent of the fuel
sulfur 1s emitted as SC^, less than 1 percent of the fuel sulfur is emitted
as SOg, and approximately 3 percent of the fuel sulfur is emitted as S0^ .
The overall removal efficiency for trace elements across the scrubber
1s 99.5 percent. Of the 22 major trace elements, 18 exceed their MATE
values at the scrubber inlet and four at the scrubber outlet. The four
trace elements 1n the scrubber flue gas that pose a potential hazard are
arsenic, chromium, Iron, and nickel. In addition, the emission concen-
tration of beryllium at the scrubber outlet 1s equal to Its MATE value.
The relative removal efficiency for trace elements across the scrubber
can be explained by enrichment theory. In general, trace elements that
8

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occur as element vapors or form volatile compounds at furnace temperatures
are more concentrated in the smaller particulates, as a result of subse-
quent condensation and surface adsorption. These are the same trace
elements that are removed less efficiently by the scrubber.
Mass balance closure for most of the trace elements have been found
to be in the 75 to 107 percent range. This closure instills confidence
on the validity of the sampling and analysis data for trace elements.
Organics
Total organic emissions were generally less than 9 ng/J (0.02 pound/
MM Btu) and these emissions appear to be primarily to Cg hydrocarbons
and hydrocarbons heavier than C^g. While uncontrolled emission rates for
C-j to C-jg and higher hydrocarbons are low, emissions of these organics were
further reduced by 21% to 35% in the scrubber unit.
Polycyclic organic material (POM) was not found in the scrubber inlet
3
or outlet at detection limits of 0.3 yg/m . MATE values for most POM's are
greater than this detection limit. However, since the MATE values for at
least two POM compounds - benzo(a)pyrene and dibenz(a,h)anthracene - are less
than 0.3 yg/m , additional GC/MS analyses at higher sensitivity would be
required to conclusively preclude the presence of all POM's at MATE levels.
Liquid Effluents
The combined wastewater stream generated from the boiler operation may
not pose an environmental hazard, since the discharge concentrations of most
inorganics and organics are all well below their MATE values. However,
based on the uncertainty in SSMS analyses, cobalt, cadmium, nickel and copper
may exceed their MATE values based on ecological considerations.
Solid Waste
The scrubber cake produced contains a significant amount of coal fly
ash. With the exception of boron, trace element concentrations in the
scrubber cake far exceeded their MATE values. Because the trace elements
may leach from the disposed scrubber cake, these solid wastes must be
disposed of in specially designed landfills.
9

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COMPREHENSIVE ASSESSMENT OF OIL FIRING
Criteria Pollutants
Uncontrolled emissions of criteria pollutants do not generally
correspond with emission factors from AP-42. NOx emissions were nearly
23% lower than the AP-42 emission factor, although they appear to be
within the normal range for similar industrial units. CO emissions were
nearly 63% lower than the AP-42 emission factor. SO^ and total hydro-
carbons corresponded well with their respective AP-42 emission factors.
Particulate emissions, in the absence of coal ash contamination, are
approximately twice the value tabulated in AP-42.
Sulfur dioxide removal data indicated an average scrubber efficiency
of 97%. Controlled S0£ emissions were 26.8 ng/J (0.06 lb/MM Btu) which
is less than either existing or proposed NSPS limitations for utility
boilers.
Inorganics
Particulate removal data indicate that, on the average, scrubber
efficiency was 84% during the test period. However, based on particulate
catches essentially free of coal ash contamination, the scrubber effi-
ciency was approximately 75% for oil firing particulates.
When emissions are uncontrolled, over 90% of the sulfur in the fuel
feed is emitted as S02> less than 1% as SOg, and 1.5% as S0^~.
SO2 is efficiently removed by the scrubber (97 to 98% efficiency).
The SOg removal efficiency (28 to 29%) suggests that SO3 is associated
with fine particulates or aerosols. S0^~ is about 60% removed by the
scrubber, and so 1s probably associated with the larger particulates.
Of the 22 major trace elements analyzed in the flue gas stream,
11 exceeded their MATE values at the scrubber inlet while only 5 exceeded
MATE values at the scrubber outlet. These 5 elements are arsenic, cadmium,
chromium, nickel and vanadium. With the exception of chromium, elements
exceeding their MATE values at the scrubber outlet were removed from the
flue gas stream with efficiencies lower than the overall average removal
efficiency of 87%.
10

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3
Beryllium emissions were 0.001 mg/m after scrubbing; this corresponds
to half the MATE value for this element. At this emission concentration, the
National Standard for Hazardous Air Pollutants limitation of 10 grams beryl-
lium per day would only be exceeded by boilers of 100 MW capacity or greater.
Mass balance closure for 10 of the 20 trace elements analyzed is between
50 and 136 percent. Poorer mass balance closure was obtained for the remain-
der of the trace elements due to the extremely low concentrations and/or
contamination of the scrubber recycle solution by coal firing components.
Organics
Organic emissions determined by FID analysis were generally less than
5 ng/J (0,01 Ib/MM Btu) and appear to be composed primarily of C] to Cg
hydrocarbons and organics heavier than Ci6. However, gas chromatograph and
gravimetric data indicate that FID values may be low by a factor of 2 to 3.
Approximately 88 and 83% of the C7 to C-jg and higher than C]g organics,
respectively, were removed by the scrubber.
The organic compounds identified in the gas samples were generally not
representative of combustion-generated organic materials, but were compounds
associated with materials used in the sampling equipment and in various analy-
tical procedures. This again confirms the low level of organic emissions.
Polycyclic organic material (POM) was not found in the scrubber inlet
or outlet streams at detection limits of 0.3 Mg/m3. MATE values for most POMs
are greater than this detection limit. However, since the MATE values for at
least two POM compounds - benzo(a)pyrene and dibenz(a,h)anthracene - are less
than 0.3 /ag/m , additional GC/MS analysis at higher sensitivity would be
required to conclusively preclude the presence of all POMs at MATE levels.
Liquid Effluents
The combined wastewater stream from the boiler operation may not pose an
environmental hazard in terms of organic materials since the discharge concen-
trations of organics are all well below their MATE values. A similar
conclusion may be drawn with respect to inorganic materials since inorganics,
with the exception of nickel and copper, did not exceed their MATE values for
liquid streams. Owing to uncertainty associated with SSMS analysis, nickel
and copper may exceed their MATE values although this 1s not necessarily the
case.
11

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Solid Waste
With the exceptions of antimony, boron, molybdenum and zinc, trace
element concentrations in the scrubber cake exceed their MATE values.
Because the trace elements may leach from the disposed scrubber
cake, these solid wastes must be disposed of in specially designed
landfills.
COMPARATIVE EMISSIONS ASSESSMENT
Criteria Pollutants
Uncontrolled emissions of criteria pollutants produced during coal
firing correspond well with emission factors from AP-42. This obser-
vation does not generally hold true for oil fired emissions. Full load
N0X emissions from oil firing were 19% lower than the AP-42 emission
factor, although they appear to be within the normal range for similar
industrial units. CO emissions from oil firing were nearly 63% lower
than the AP-42 emission factor. 011-fired SOg and total hydrocarbons
correspond well with their respective AP-42 emission factors. Particu-
late emissions from oil firing, 1n the absence of coal ash contamination,
are approximately twice the value tabulated in AP-42.
N0X emissions Increased with increasing load for both coal and oil
firing, as expected. Available data indicate that for boiler loadings
between 90 and 100%, N0X emissions from coal firing are approximately
three times greater than from oil firing.
Observed reductions of N0X emissions for coal firing and early oil
firing tests appear to be due, at least in part, to air leakage into the
scrubber outlet sampling line. Data from later oil firing tests, not
known to be subject to leakage problems, indicate that N0X removal across
the scrubber is on the order of 2%.
Uncontrolled CO emissions from coal firing were 15.9 ng/J (0.04 lb/
MM Btu) while those from oil firing were 5.47 ng/J (0.01 lb/MM Btu). This
factor of three difference 1s at variance with AP-42 data indicating that
CO emissions from oil firing are 23% lower than those from coal firing.
Apparent reductions in CO emissions across the scrubber are not considered
12

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significant due to air leakage in the sampling train and the low
sensitivity of analysis at the measured CO concentrations.
Uncontrolled SO^ emission rates during coal and oil firing were
1112 ng/J (2.59 lb/MM Btu) and 993 ng/J (2.31 lb/MM Btu), respectively.
Removal data indicate an average scrubber removal efficiency of 97% during
both coal and oil firing. Controlled S02 emissions for coal and oil fir-
ing were 36.3 ng/J (0.08 lb/MM Btu) and 26.8 ng/J (0.06 lb/MM Btu),
respectively, which are lower than either existing or proposed NSPS
1 imitations.
Particulate loadings prior to scrubbing were 2951 ng/J (6.86 lb/MM
Btu) during coal firing and 59.0 ng/J (0.14 lb/MM Btu) during oil firing,
in the absence of coal ash contamination. Scrubbing removed 99% of the
coal-fired particulates and 75% of the oil-fired particulates. The lower
removal efficiency obtained during oil firing is attributed to the
increased fraction of particles smaller than 3ym; at least 21% of the
uncontrolled oil-fired particulates are less than 3 ym in diameter while
substantially less than 1% of uncontrolled coal-fired particulates are
under 3 urn.
There appeared to be a net increase in emission rates across the
scrubber for coal fired particulates less than 3 ym 1n size. This net
Increase can be attributed to the poor removal efficiency of the scrubber
for fine particulates, and to the sodium blsulfate (NaHSO^ and calcium
sulfite hemihydrate (CaS03 • 1/2H20) particulates generated by the
scrubber. Both NaHSO^ and CaSOg *1/2^0 have been identified at the
scrubber outlet but not at the inlet. Although a very slight increase
in oil-fired particulates in the 1-3 ym range was observed, a net
decrease in particulates less than 3ym was observed during oil firing.
Based on the results of coal firing tests, it appears reasonable that
scrubber generated particulates were present In the scrubber outlet stream
during oil firing but that the high fine particulate loading associated
with oil firing masked detection of these materials.
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Inorganics
Of the 23 major trace elements analyzed in the flue gas stream
during coal firing, 18 exceed their MATE values at the scrubber inlet
and four at the scrubber outlet. Similarly, for oil firing, 11 exceeded
their MATE values at the scrubber inlet while five exceeded their MATE
values at the scrubber outlet. Elements exceeding their MATE values at
the scrubber outlet and which are common to both fuels are arsenic, chro-
mium and nickel. Additionally, iron exceeded its MATE value at the
scrubber outlet during coal firing as did cadmium and vanadium during oil
firing. The overall removal of trace elements across the scrubber is 99%
for coal firing and 87% for oil firing.
Beryllium emissions after scrubbing were less than or equal to the
beryllium MATE value during coal and oil firing. At the measured emis-
sion concentrations, the National Standard for Hazardous Air Pollutants
limitation of 10 grams beryllium per day would only be exceeded by
boilers of 50 MW capacity for coal firing and 100 MW capacity for oil
firing.
The fraction of fuel sulfur converted to S03 during oil firing was
50 to 75% higher than during coal firing. In contrast, the fraction of
fuel sulfur converted to sulfates during coal firing was twice that
during oil firing.
Sulfates are more efficiently removed than SOj (60% removal for oil
firing and 88% for coal firing). This Indicates that S0^~ is probably
associated with the larger particulates, which are more efficiently
removed than smaller particulates. The higher sulfate removal from the
coal flue gases is explained by the higher particulate loading during
coal firing.
Uncontrolled chloride and fluoride loadings were higher during coal
firing (5 and 0.2 ng/J, respectively) than during oil firing (0.2 and
0.02 ng/J, respectively). This was attributed, 1n the case of chlorides,
to a higher fuel chlorine content for coal than for oil. Chlorides were
removed with better than 99% efficiency from coal flue gases and with
about 51% efficiency from oil flue gases. This difference was attributed
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to the higher particulate removal efficiency for coal particulates.
Fluorides were removed with greater than 86% and about 87% efficiency for
coal and oil firing, respectively. Uncontrolled nitrate emissions were
0.08 ng/J during oil firing, and nitrates were removed from oil flue gases
with 57% efficiency.
Orqanics
Polycyclic organic material (POM) was not found in the scrubber inlet
or outlet at detection limits of 0.3 jjg/m3 for either coal or oil firing.
MATE values for most POM's are greater than this detection limit. However,
since the MATE values for at least two POM compounds - benzo(a)pyrene and
dibenz(a ,h)anthracene - are less than 0.3 pg/m3, additional GC/MS analyses
at higher sensitivity would be required to conclusively preclude the
presence of all POM's at MATE levels.
Organic emissions for coal and oil firing were very similar. Total
organic emissions were less than 9 ng/J (0.02 Ib/MM Btu) for both tests,
and these emissions appear to be primarily C] to Cg hydrocarbons and
organics heavier than C-jg. While uncontrolled emission rates for both
coal and oil firing are low, emissions of these organics were further
reduced by about 75% to 85% in the scrubber unit.
The organic compounds identified in the gas	samples from both coal
and oil firing were generally not representative	of combustion-generated
organic materials, but were compounds associated	with materials used in
the sampling equipment and in various analytical	procedures. This again
confirms the low level of organic emissions.
Liquid Waste
The combined waste water stream from the boiler operation may
not pose an environmental hazard in terms of organic materials since
the discharge concentrations of organics are well below their MATE values
for both coal and oil firing. The same conclusion may be drawn for inor-
ganic compounds with the exception of cobalt, nickel, copper and cadmium
for coal firing and nickel and copper for oil firing since these metals
may exceed their MATE values.
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Solid Waste
The scrubber cake produced when either fuel is burned contains
concentrations of trace elements high enough to exceed most MATE values.
Because of these high concentrations the scrubber cake must be disposed
of in specially designed landfills.
COMPARATIVE ENVIRONMENTAL ASSESSMENT
The difference in environmental insult expected to result between coal
and oil combustion emissions from a single controlled 10 MW industrial
boiler is insignificant. This is because: 1) there are only slight differen-
ces in the emissions levels of the pollutants, or 2) the absolute impact of
either fuel use is insignificant. The environmental impacts of emissions from
a cluster of controlled 10 MW industrial boilers are potentially significant.
The impacts include health effects, material damages, and ecological effects
from high levels of SO^, N0X and suspended particulate matter; health effects
and ecological damage due to trace metal accumulation in soils and plants;
and aesthetic degradation from visibility reduction and waste disposal sites.
The risk of environmental damage from emissions of controlled industrial
boilers, whether oil or coal-fired, is considerably less than the risk posed
by emissions from uncontrolled industrial boilers. It should be noted that
this finding is based on an exceptional facility. The reference facility
1s very well run and maintained, and emissions are low.
The environmental acceptability of a cluster of controlled industrial
boilers is more dependent on site specific factors (e.g., background
pollution levels, location and number of other sources) than type of fuel
utilized. Careful control of the site specific factors can avert potential
environmental damages and generally compensate for any differential effects
arising between the use of coal or oil .
With the possible exception of ambient levels of N0xğ the risk of
violating the National Ambient Air Quality Standards (NAAQS) due to the opera-
tion of clusters of controlled Industrial boilers is essentially the same
whether the fuel combusted is coal or oil. Based on tests of the reference
10 MW boiler (which was not controlled for N0X emissions), localized N0X
concentrations produced by coal firing are estimated to be twice the level of
that resulting from oil firing, and greater than the levels permitted by the
NAAQS for 24-hour and one year averaging periods.
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Short term (3 hour and 24 hour averaging times) maximum ambient
concentrations present the most significant air pollution problem result-
ing from operation of controlled industrial boilers. Restrictions
imposed by the NAAQS for short term ambient levels would be most con-
straining to boiler operation in areas where air quality is already only
marginally acceptable. Expected long term concentrations arising from
boiler emissions would not appear to pose a risk for violation of the
NAAQS.
Coal firing appears to produce a greater enrichment of trace elements
in the flue gas desulfurization cake than oil firing produces. However,
the scrubber cake resulting from either coal or oil firing contains
sufficient amounts of heavy metals and toxic substances to pose difficult
waste disposal problems.
The impact categories considered include public health, ecology,
societal, economic, and energy. The specific findings with respect
to the various Impact categories are summarized briefly below.
Health Effects
Based on the Lundy/Grahn Model for health effects associated with
suspended sulfate levels, regional emissions levels from controlled oil
or coal-fired industrial boilers would not be expected to cause a signi-
ficant impact on regional health. Emissions from uncontrolled boilers
would result in substantially greater levels of regional suspended sulfate
levels, and the associated health effects would be an order of magnitude
greater.
Emissions from clusters of controlled industrial boilers are expected
to cause significant adverse health effects in a localized area near the
plant cluster. Oil firing would be expected to result in localized health
effects about one third less severe than those resulting from coal firing.
The increase in mortality attributable to either controlled coal or oil
firing is appreciable less than that associated with uncontrolled industrial
boilers emitting higher levels of particulates and S0X.
The impact of solid waste generation on health is essentially the
same for controlled coal firing and oil firing, provided suitable land
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disposal techniques are employed to assure minimal leaching rates and
migration of trace elements to groundwater and the terrestrial
environment.
Addition of cadmium to a localized environment in the quantities
produced by clustered controlled industrial boilers may result in cadmium
concentrations in living plants approaching levels injurious to man.
Because cigarettes contain significant cadmium levels, smokers are more
apt to achieve thresholds of observable symptoms for cadmium exposure when
consuming additional cadmium via the food chain.
The concentration of metals 1n runoff waters due to controlled oil
firing is predicted to be slightly less than that occurring from controlled
coal firing; in either case, hazard to human health by drinking water is
remote.
Trace element emissions from clusters of controlled industrial
boilers may significantly increase local background levels in drinking
water, plant tissue, soil, and the atmosphere; however, the expected
Increases in the levels of such elements are generally several orders of
magnitude less than allowable exposure levels. Oil firing is estimated
to cause cadmium burdens in plants approaching levels injurious to man,
and coal firing may produce plant concentrations of molybdenum which are
injurious to cattle.
Ecology
The potential for crop damage from either controlled coal firing or
oil firing depends greatly on ambient levels of N0xğ SO2, or trace element
soil concentrations. If such levels are presently high, localized plant
damage would be expected to occur within a 1 to 2 km range from a control-
led boiler cluster. Leaf destruction from SOg exposure would be expected
to be slightly more severe 1n the vicinity of a cluster of controlled
boilers which are coal fired as opposed to oil fired. For boilers uncon-
trolled for N0X emissions, plant damage would be expected to be
significantly greater in the vicinity of the coal-fired cluster, owing to
higher levels of ambient N0X produced. The likelihood of damage occuring
in plants due to emissions of trace elements from either controlled oil or
coal firing is remote, with the possible exception of injury due to elevated
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levels of molybdenum and cadmium 1n plant tissue resulting from coal
firing and oil firing, respectively.
The effect of emissions from industrial boilers on trace element
burdens in plants would be greater via soil uptake than by foliar inter-
ception. This is because soil concentrations are the result of accumu-
lative long term exposure to boiler emissions whereas foliar exposure is
determined by the immediate deposition rate of emissions on the plant
surface and the lifetime of the leaf.
The impact of fossil fuel combustion in controlled oil or coal-
fired boilers on plant damage via acid precipitation would be
insignificant. The levels of suspended sulfate (the origin of acid rain)
would be essentially the same whether the controlled boilers are coal or
oil fired.
Measurement and analyses of leaching rates at experimental waste
disposal sites indicate that landfills of untreated flue gas desulfuri-
zation system scrubber cake can be constructed such that significant
adverse impacts will not occur.
Societal
The impact of boiler emissions on corrosion in the local area near
a cluster of controlled industrial boilers would be significant. The
corrosion rate would be slightly greater when the boilers are coal-fired.
However, the extent of this overall impact (oil or coal) is minor compared
to that which occurs when industrial boilers are uncontrolled.
The increase in annual TSP and soiling damages in the vicinity of a
cluster of controlled industrial boilers would result in additional cleaning
and maintenance costs about 10 to 15% greater than that already experienced
in a typical urban area. The cleaning costs may be slightly greater when
the boilers are coal-fired.
Emissions of particulate matter from controlled Industrial boilers would
result in visibility reduction. This aesthetic degradation would occur
in a localized area near the boiler cluster, and would occur to essentially
the same extent whether the boilers are oil or coal fired.
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Total land disposal requirements for scrubber cake waste generated by
controlled coal firing are three times greater than those for controlled
oil firing. Waste disposal of the scrubber wastes may result in significant
depreciation of property value and aesthetic degredation in the area of the
disposal site. These impacts would be more severe if boilers use coal
rather than oil.
Economic
The differential direct economic impact between emissions from coal
firing and oil firing is generally insignificant with the possible
exception of some differences occurring in a limited localized area near
clusters of boilers. The extent of the incremental direct economic
impacts is proportional to the extent of the incremental environmental
damages.
Differential second order economic impacts, such as changes in
hospital employment, alteration of taxes, or changes in income, are expected
to be insignificant between emissions from controlled oil and coal-fired
industrial boilers.
Energy
At the present time, the comparative assessment of the effects of
emissions from controlled oil and coal-fired industrial boilers tends to
support the national energy plan for intensified utilization of coal. The
fuel choice of oil or coal is a relatively minor issue concerning the
environmental acceptability of controlled industrial boilers; other site
specific and plant design factors exert a greater effect on environmental
damages. While it was shown that fuel choice caused significant dif-
ferences in impacts to occur when the boiler is uncontrolled for N0X
emissions, these differences may be mitigated by the addition of N0X control
technologies with minimal overall cost impact.
As concern for environmental protection increases, the issue may not be
whether coal or oil use is more environmentally acceptable, but whether the
Increasing use of fossil fuels can be continued at the present levels of
control technology without potential long term damages. If it is found
that long term effects of pollution (e.g., trace metals accumulation, lake
acidity from acid rains) from fossil fuel combustion and other sources are
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environmentally unacceptable, it is clear that energy use may be affected.
Energy cost will Increase with increasing control requirements, possibly
to the level where other cleaner forms of energy become more competitive.
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO. 2.
EPA-600/7-78-164a
3. RECIPIENT'S ACCESSION NO.
4. title and subtitle Environmental Assessment of Coal-
and Oil-firing in a Controlled Industrial Boiler;
Volume I. Executive Summary
S. REPORT DATE
August 1978
6. PERFORMING ORGANIZATION CODE
7.author(s) c. Leavitt, K. Arledge, C. Shih, R. Orsini,
W. Hamersma, R. Maddalone, R. Beimer, G. Richard, and
M. Yamada
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
TRW, Inc.
One Space Park
Redondo Beach, California 90278
10. PROGRAM ELEMENT NO.
EHE624A
11. CONTRACT/GRANT NO.
68-02-2613, Task 8
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT AND PERIOD COVERED
Task Final; 5/77-7/78
14. SPONSORING AGENCY CODE
EPA/600/13
15.supplementary NOTES jerl-RTP project officer is Wade H. Ponder, Mail Drop 61, 919/
541-2915.
16. abstract The rep0rt gives results of a comparative multimedia assessment of coal-
versus oil-firing in a controlled industrial boiler, to determine relative environmen-
tal, energy, economic, and societal impacts. Comprehensive sampling and analyses
of gaseous, liquid, and solid emissions from the boiler and its control equipment were
conducted to identify criteria pollutants and other species. Major conclusions include:
(1) While the quantity of particulates from oil-firing is considerably less than from
coal-firing, the particles are generally smaller and more difficult to remove, and the
concentration of particulates in the treated flue gas from oil-firing exceeded that from
coal-firing. (2) NOx and CO emissions during coal-firing were about triple those du-
ring oil-firing. (3) Sulfate emissions from the boiler during coal-firing were about
triple those during oil-firing; however, at the outlet of the control equipment, sulfate
concentrations were essentially identical. (4) Most trace element emissions (except
vanadium, cadmium, lead, cobalt, nickel, and copper) are higher during coal-firing.
(5) Oil-firing produces cadmium burdens in vegetation approaching levels which are
injurious to man; coal-firing may produce molybdenum levels which are injurious to
cattle. (6) The assessment generally supports the national energy plan for increased
use of doal by projecting that the environmental insult from coal-firing is not signif-
icantlv different from that from oil-firing.
17. KEY WORDS AND DOCUMENT ANALYSIS
a. DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Pollution Nitrogen Oxides
Assessments Carbon Monoxide
Boilers Sulfates
Combustion Sulfur Oxides
Fuel Oil Trace Elements
Coal Chemical Analysis
Dust
Pollution Control
Stationary Sources
Environmental Assess-
ment
Industrial Boilers
Particulate
13B 07B
14B
13A
21B
2 ID 06A
07D
11G
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
26
20. SECURITY CLASS /This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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