Tennessee
Valley
Authority
United States
Environmental Protection
Agency
Office of Power
Power Research Staff
Chattanooga, Tennessee 37401
Office of Research and Development
Office of Energy, Minerals, and Industry
IERL, Research Triangle Park, NC 27711
EPA-600/7-77-010
January 1977
CHARACTERIZATION
OFASH FROM
COAL-FIRED POWER PLANTS
Interagency
Energy-Environment
Research and Development
Program Report
-------
RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S.
Environmental Protection Agency, have been grouped into seven series.
These seven broad categories were established to facilitate further
development and application of environmental technology. Elimination
of traditional grouping was consciously planned to foster technology
transfer and a maximum interface in related fields. The seven 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
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 systems. The goal of the Program
is to assure the rapid development of domestic energy supplies in an
environmentally—compatible manner by providing the necessary
environmental data and control technology. Investigations include
analyses of the transport of energy-related pollutants and their health
and ecological effects; assessments of, and development of, control
technologies for energy systems; and integrated assessments of a wide
range of energy-related environmental issues.
This document is available to the public through the National Technical
Information Service, Springfield, Virginia 22161.
-------
EPA-600/7-77-010
January 1977
CHARACTERIZATION OF ASH
FROM COAL-FIRED POWER PLANTS
by
S. S. Ray and F. G. Parker
Tennessee Valley Authority
Power Research Staff
Chattanooga, Tennessee 37401
Interagency Agreement No. D5-E-721
Program Element No. EHB 557
Project Officer
Julian W. Jones
Industrial Environmental Research Laboratory
Office of Energy, Minerals, and Industry
Research Triangle Park, NC 27711
This study was conducted
as part of the Federal
Interagency Energy/Environment
Research and Development Program.
Prepared for
OFFICE OF ENERGY, MINERALS, AND INDUSTRY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, DC 20460
-------
DISCLAIMER
This report was prepared by the Tennessee Valley Authority and has been
reviewed by the Office of Energy, Minerals, and Industry, U. S. Environ-
mental Protection Agency, and approved for publication. Approval does
not signify that the contents necessarily reflect the views and policies
of the Tennessee Valley Authority or the U. S. Environmental Protection
Agency, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
-------
ABSTRACT
This report presents a summary of existing data on the chemical and physical
characteristics of ashes produced by the burning of coal in steam-electric
generating plants. Several recent coal or ash characterization studies are
summarized; emphasis is placed on the elemental chemical composition, partic-
ularly trace inorganic constituents. General agreement among the studies is
found regarding partitioning of trace elements among the bottom ash, fly ash,
and flue gas. Coal and ash analysis methods are examined to aid in evaluation
and comparison of results from studies which do not all use identical analyti-
cal methods. The need for a standard set of analytical procedures for coal
and ash is evident. The physical and chemical characteristics of sulfur
dioxide scrubbing sludges are also summarized because these materials are
becoming a significant portion of total power plant residues.
This report was submitted by the Tennessee Valley Authority Power Research
Staff in partial fulfillment of Energy Accomplishment Plan No. 77BBC under
terms of Interagency Energy Agreement No. D5-E-721 with the Environmental
Protection Agency.
ill
-------
CONTENTS
Abstract ................................ iii
Figures ................................ v
Tables ................................ vi
Conversion Table ............................ ix
1. Introduction .......................... 1
2. Conclusions ........................... 2
3. Recommendations ......................... **•
k. Summary and Discussion ................. .... 5
5. Coal Characterization ...................... 11
General .......................... 11
Origin ...... ......... .... ....... . 11
Characterization ...................... Ik
6. Physical Characterization of Ash ................ 28
General .......................... 28
Comparison of Ash from a Mechanical Collector
and Electrostatic Precipitator .............. 35
7. Chemical Characterization of Ash ................ kz
Chemical Composition by Coal Rank and by Ash Fraction. ... 1+2
Analytical Studies ..................... kZ
Methods for Chemical Analysis of Coal and Fly Ash. ..... 88
8. Modified Ash . . „ . . . ....................
References ............................... 117
Bibliography .............................. 122
iv
-------
FIGURES
Number Page
1 ASOM Classification of Coals by Rank 12
2 Coal Fields of the Counterminous United States 13
3 Pulverized-Coal Firing Methods 29
k Grain Size Distribution Curves for Bottom Ash and Fly Ash .... 32
5 Particle Size Distribution of Fly Ash 33
6 Enrichment Factors of Various Elements on Suspended Particles in
the Stack with Respect to the Concentrations in the Coal 57
7 Sample Points and Flow Rates for Valmont, Unit No. 5 58
8 Sample Points for Allen Steam Plant, Unit No. 2 62
9 Schematic of Sampling Locations for Soil Cores, Fallout, and
Environmental Air Samples 63
10 Temperature History of Flue Gases 87
v
-------
TABLES
Number Page
1 Amounts of Elements Mobilized Into the Atmosphere as a Result of
Weathering Processes and the Combustion of Fossil Fuels 7
2 Partition of Elements by their Tendencies for Distribution in
Coal Combustion Residues 9
3 Variations in Coal Ash Composition with Rank 16
k Concentrations of Trace Elements in Coal 17
5 Trace Elements in Ashes of Coal and in the Earth's Crust .... 2k
6 Enrichment of Elements During Decay of Oak and Beech Humus;
Percent of Ash 25
7 Quantitative Analyses (in ppm) for 13 Trace Elements in Drill-
Core Coal Samples, Powder River Basin 26
8 Comparison of Distribution Between Bottom Ash and Fly Ash by
Type of Boilers and Method of Firing 30
9 Comparison of Particle Size Distribution by Three Methods of
Determination 3U
10 Particle Size Distribution of Ash from a Mechanical Collector . . 36
11 Particle Size Distribution of Ash from an Electrostatic
Precipitator 37
12 Surface Area by Three Methods 38
13 Chemical Analysis 39
lh Phase Composition l^
15 Range in Amount of Trace Elements Present in Coal Ashes 1+3
16 Comparison of Fly Ash and Bottom Ash from Various Utility Plants. k6
17 Concentrations of Trace Elements in Coal Fly Ash and Flue Gas . . 1^.7
vi
-------
TABLES
(continued)
Number Page
18 Elements Showing Pronounced Concentration Trends with
Decreasing Particle Size .................... 53
19 Elements Showing Limited Concentration Trends with
Decreasing Particle Size .................... 5^
20 Elements Showing No Concentration Trends ............ 55
21 Trace Elements in Plant Samples from Valmont Power Station
Unit No. 5 ........................... 59
22 Closure of Mass Balance .................... 60
23 Tabulation of Elemental Concentrations and Mass Balance Results
from Allen Steam Plant ..................... 6k
2k Major Element Data for Soil Samples Collected from a UO-Mile
North-South Transect at the Allen Steam Plant ......... 71
25 Minor Element Data for the Top 1 Cm of Soil Collected from a
North-South Transect at the Allen Steam Plant ..... 72
26 Minor Element Concentrations in Sediments and Water Collected in
the Immediate Vicinity of the Allen Steam Plant ........ 73
27 Mercury Concentrations in Masses Expressed as a Function of
Distance North and South of the Allen Steam Plant ....... 7^
28 Comparison of Elemental Concentrations in Soils Collected in the
Allen Steam Plant Environmental Study with World Averages ... 75
29 Analytical Results of the Station 1 Samples ........... 79
30 Analytical Results of the Station II Samples .......... 80
31 Analytical Results of the Station III Samples ......... 8l
32 Pollutant Concentration in Coal, Ash, and Flue Gas Streams at
Widows Creek Steam Plant .................... 82
33 Volatility of Trace Elements in Coal .............. 89
vii
-------
TABLES
(continued)
Number
3^ Concentration and Size of Trace Metal Particles in Urban Air . . 90
35 Trace Metals in Fly Ash as a Function of Particle Size 91
36 Percent Particle Mass as Function of Size 92
37 Coal Analysis Comparison for Trace Elements by Laboratory and
by Analytical Method 98
38 Fly Ash Analysis Comparison for Trace Elements by Laboratory
and by Analytical Method 100
39 Elemental Concentrations in EBS Coal (SRM 1632) 102
kO Elemental Concentrations in MBS Fly Ash (SRM 1633) 103
hi Chemical Composition of Lime Process Scrubber Sludge on Dry
Solid Basis 105
h2 FGD Systems Sampled as Data Base 107
h3 Phase Composition of FGD Waste Solids in Weight Percent .... 109
hh Dewatered Bulk Densities of FGD Wastes 110
45 Permeability of Untreated and Chemically Fixed FGC Wastes . . . Ill
h6 Identification of APCS Sludge Standards 113
h7 Wet Chemical Analysis of Sludge Standards 114
h8 Chemical Analysis of Lime Process Sludges in Percent on Dry
Solid Bases 116
vn
-------
CONVERSION TABLE
A list of conversion factors for British units used in this report
is as follows:
British
1 inch
1 foot
1 mile
1 pound
1 ton (short)
1 gallon
1 part per million
1 part per billion
1 British thermal unit per pound
Metric
2.54 centimeters
0.3048 meter
1.609 kilometers
0.454 kilogram
0.9072 metric tons
3.785 liters
1 milligram per liter (equivalent)
.001 milligram per liter (equivalent)
2.235 Joules- per gram
IX
-------
SECTION 1
INTRODUCTION
The passage of the Federal Air Quality Act in 1970 necessitated exa-
mination of the impact of steam-electric power plants on the atmospheric
environment. Subsequent passage of the Federal Water Pollution Control
Act of 1972 (PL 92-500) and the resulting requirement that National
Pollutant Discharge Elimination System p ermits be obtained at all
steam plants have made it important to determine the overall impact
a steam-electric power plant will have on the aquatic environment as
well. Thus, it is essential that air emissions and water discharges
from such plants be characterized.
The combustion of coal produces a residue composed of inorganic mineral
constituents and incompletely burned organic matter. During the com-
bustion process potentially hazardous pollutants are released, some
of which are introduced into the environment. As the quantity of coal
utilized increases, the amounts of these potential pollutants produced
grows proportionately. Some trace elements found in coal and ash are
toxic to certain plants and animals at relatively low concentrations.
Therefore, characterization of combustion products is increasingly
important for assessment of the concentrations, the amounts, and the
forms in which pollutants may be released to the environment.
Additionally, characterization of coal ash will later be helpful in
determining new and more extensive uses or inproved disposal methods
for this combustion product. At present a relatively small proportion
(about 14 to 16 percent) of ash is utilized; the remainder presents a
significant disposal problem.
The purpose of this report is to present a sunmary of existing data on
the chemical and physical characteristics of coal ashes produced by
the burning of coal in steam-electric generating plants.
This report addresses the characteristics of the coals from which the
ashes are derived as well as those of the ashes themselves. Several
recent studies concerned with the characteristics of coal, ash, or ash
effluents are examined, with emphasis on the elemental chemical composi-
tion of the coals and their ashes, particularly the trace inorganic con-
stituents. Methods for the chemical analysis of ash and coal matrices
are examined to aid the evaluation and comparison of results from studies
which did not all use the same analytical methods. The physical and
chemical characteristics of sulfur dioxide scrubbing sludges are also
summarized because these materials are becoming a significant portion of
total power plant residues.
-------
SECTION 2
CONCLUSIONS
The use of coal, the most widely distributed fuel in the United States, is
increasing at a rapid rate. In 1974 the utilities industry utilized 390
million tons; it is estimated that by 1984 this industry will use 800 million
tons per year. The coal used in the future may contain greater amounts of
ash, as coal seams with larger ash proportions are increasingly explored and
utilized. The combination of these two factors, greater coal usage and
larger proportions of ash, will result in increasing total amounts of ash
residues.
Many elements are enriched in coal, compared to their abundance in the
earth's crust, and enriched in ash, compared to their concentrations in the
coal.
Analytical studies of coal and its combustion residues generally agree that
elements are partitioned into three main groups with respect to their
distribution in the residues, as follows.
1. Group I - Elements which are approximately equally distributed in
the bottom ash and the flyash.
2. Group II - Elements which are preferentially concentrated in the
flyash as compared to the bottom ash.
3. Group III - Elements which are primarily emitted to the atmosphere
as gaseous species.
The theory for this partitioning effect involves the volatilization of some
elements or their compounds in the furnace. Subsequently, some of these
vaporous phase elements recondense, either partially or completely; others
are discharged through the stack as gases. Elements with volatilization
temperatures higher than that reached in the boiler remain about evenly
distributed in the two ash fractions (Group I). Others are volatilized and
are not cooled sufficiently to condense (Group III). Elements which do con-
dense generally form fine particles or are deposited onto the surface of
small particles (Group II).
The finer particulates in flyash are a particular source of environmental
concern, because three factors combine to make them an especial risk over
that presented by larger particles.
-------
Fine particulates have proportionally higher concentrations of
many potentially hazardous trace elements.
They pass through collection devices and are emitted to the
atmosphere in greater proportions.
They enter more easily into the human respiratory system and are
retained for longer periods.
-------
SECTION 3
RECOMMENDATIONS
In order to better assess the impact of power plant emissions and effluents
and to improve ash disposal and utilization practice, a more complete under-
standing is needed of potentially hazardous pollutants generated by power
plants, including the quantities, and the distributions among various power
plant emissions/effluents. Several studies have been made to determine the
pollutant quantities and distributions but more work in these areas would
better define potential environmental effects.
A problem encountered in previous studies has been the difficulty of obtain-
ing representative samples from the various effluent streams, especially of
the gases and fine particulates in stack emissions. The two-phase flows in
bottom ash and flyash sluicing waters are another example of this problem.
It is suggested that research be continued toward the development of improved
sampling instrumentation and the recommendation of uniform, standardized
techniques.
Results from analytical studies on power plant residues are not always com-
parable, because of differences in analytical methods used to determine
particular elements and in sample preparation and handling. These sources
of error are in addition to the normal interlaboratory data dispersion which
occurs when multiple institutions prepare and analyze the same sample using
identical techniques. It is recommended that standard analytical practices
be developed for general usage for trace elements in the coal and ash
matrices.
As stricter air pollution laws proliferate, new combustion methods, coal
preparation, or residue treatments will be required to comply with these
laws. Most of the concepts proposed to meet these laws (such as flue gas
desulfurization, coal liquefaction and gasification, increased usage of
certain types of coals, and new power plant designs) will result in increased
quantities and/or altered characteristics of power plant residues. Research
is needed into the characteristics of these products, as well as into the
distribution of possibly hazardous trace elements and other pollutants
contained in the residues.
In order to identify the extent of the impact which the ash stored in ash
ponds may have on the environment, it is suggested that studies be conducted
on the leachability of trace elements from the pond into the surrounding
soils and groundwater.
-------
SECTION 4
SUMMARY AND DISCUSSION
Coal, the most widely distributed fuel in the United States, is found in
38 states. The nation's total coal resources have been estimated at about
4 trillion tons, nearly half of which is thought to be recoverable reserves.
The coals from the wide range of locations across the country include fuels
varying significantly with respect to heat content, ash content, and chemical
properties.
Coalification resulted from the subjection of peat (plant debris) swamps to
high temperature and pressure for millions of years. The degree of coali-
fication depends on the degree of heat and pressure. The ash content of
the coal thus formed was influenced by the extent to which overburden mate-
rial was dispersed throughout the coal seam. Trace elements carried by
rainwater, streams, or surface waters were deposited in the peat swamps and
thus incorporated into the coal.
The major elemental components of coal are carbon, hydrogen, oxygen, nitro-
gen, and sulfur. Organic constituents were derived from the decay of plant
material, while inorganic constituents were derived from the earth's crustal
formations which surrounded the peat swamp. Many trace elements have been
shown by the Bureau of Mines to be concentrated in coals with respect to
their concentrations in the earth's crust.
Coal combustion results in a residue consisting of the inorganic mineral
constituents in the coal and the organic matter which is not fully burned.
The inorganic mineral constituents, whose residue is ash, make up from 3 to
30 percent of the coal. During combustion, this ash is distributed into two
parts, bottom ash (collected from the bottom of the boiler unit) and flyash
(most of which is collected by air pollution control equipment through which
the stack gases pass). A third residue, vapors, is that part of the coal
which is volatilized in the furnace. Most of the vapors are emitted to the
atmosphere in the stack gas.
The distribution of ash between the bottom and flyash fractions is a function
of the following:
1. Boiler type (firing method). The type of firing is perhaps the
most important factor in determining ash distribution. Stoker
fired units emit the smallest proportion of flyash. In cyclone
-------
units 80-85 percent of the ash is melted and collected as slag.
Pulverized coal units produce 60 to 85 percent flyash and the
remainder bottom ash.
2. Coal type (ash fusion temperature). Ashes with lower fusion
temperatures tend to melt within the furnace and, therefore, to
be collected as bottom ash.
3. Wet or dry bottom furnace. Wet bottom boilers are designed to
produce and process a much larger proportion of bottom ash than
are dry bottom boilers.
Flyash makes up from 10 percent to 85 percent of the coal ash residue and
occurs as spherical particles, usually ranging in diameter from 0.5 to 100
microns. Color varies from light tan to black, depending on the carbon
content. An interesting portion of flyash is made up of very lightweight
particles called cenospheres, which comprise up to 20 percent by volume of
the flyash. These cenospheres are spheres of silicate glass filled with
nitrogen and carbon dioxide which range from 20u to 200y in diameter. They
are "floaters" which create a suspended solids problem in pond disposal of
ash. The chemical composition of cenospheres is very similar to that of
flyash.
The bottom ash, composed primarily of coarser, heavier particles than the
flyash, ranges from gray to black in color and is generally angular with a
porous surface. If it is collected as a slag, these slag particles usually
are black, angular, and have a glass-like appearance.
Petrographic analysis has shown that glass is the primary component of ash,
constituting 50-90 percent of the total weight. Finer particles generally
contain a higher proportion of the glass constituent than the coarser ones.
Other components of the ash include magnetite, hematite, carbon, mullite,
and quartz.
The chemical characteristics of ash depend largely on the geologic and
geographic factors related to the coal deposit. The major constituents of
ash—primarily silicon, aluminum, iron, and calcium—make up 95 to 99 percent
of the total composition. Minor constituents, such as magnesium, titanium,
sodium, potassium, sulfur, and phosphorus, comprise 0.5 percent to 3.5
percent. Ash also contains trace concentrations of from 20 to 50 elements,
including, for example: antimony, arsenic, barium, beryllium, boron, copper,
fluorine, lead, manganese, mercury, molybdenum, nickel, selenium, tellurium,
thallium, tin, titanium, uranium, vanadium, and zinc.
With the steady growth in coal utilization in this country, the quantities
of potentially hazardous pollutants entering the environment as the result
of coal combustion increase also. Table 1 displays the amounts of elements
mobilized into the atmosphere each year as a result of weathering processes
and the combustion of fossil fuels. Many of these elements are mobilized
into the atmosphere in excess of 1000 tons per year (1 X 109 grams=1100
tons). The full impact of these pollutants is unknown.
6
-------
TABLE i. AMOUNTS OF ELEMENTS MOBILIZED INTO THE ATMOSPHERE AS A RESULT OF
WEATHERING PROCESSES AND THE COMBUSTION OF FOSSIL FUELSa (l)
Element
Beryllium
Boron
Sodium
Aluminum
Chlorine
Calcium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Arsenic
Selenium
Molybdenum
Cadmium
Tin
Barium
Mercury
Lead
Fossil fuel
concentration
(ppm)
Coal
3
75
2,000
10,000
1,000
10,000
500
25
10
50
10,000
5
15
15
50
5
3
5
2
500
0.012
25
Oil
o.oooU
0.002
2
0.5
5
0.1
50
0.3
0.1
2.5
0.2
10
0.1^
0.25
0.01
0.17
10
0.01
0.01
0.1
0.3
Fossil fuel
mobilization
(X 109 g/year)
Coal
O.Ul
10.5
280
1^00
lUo
lUOO
70
3.5
l.H
7
1^00
0.7
2.1
2.1
7
0.7
O.U2
0.7
0.28
70
0.0017
3.5
Oil
0.00006
0.0003
0.33
0.08
0.82
0.02
8.2
0.05
0.02
0.1*1
0.03
1.6
0.023
0.0k
0.002
0.03
1.6
0.002
0.002
0.02
1.6
0.05
Total
O.Ul
10.5
. 280
lUoo
lif-00
70
12
1.5
7
.1^00
0.7
3-7
2.1
7
0.7
O.U5
2.3
0.28
70
1.6
3.6
Weathering
mobilization
(X 109 g/year)
River flow
360
230,000
1^,000
5^0,000
180
32
36
250
2l|,000
7-2
11
250
720
72
7.2
36
360
2.5
110
Sediments
5-6
-
57,000
1^0,000
280,000
70,000
9,000
280
200
2,000
100,000
8
160
80
80
28
0.5
11
500
1.0
21
table is condensed from that of Bertine and Goldberg.
1
-------
Several studies have been made recently to determine the concentrations of
these trace elements in the coal combustion residues. These studies were
conducted on different sizes and types of systems with respect to megawatt
output, collector configuration, boiler type, and operating conditions.
Even the purposes of the studies differed. Yet, they were in fairly close
agreement as to their findings on the distribution of elements among different
fractions of the combustion residues.
Most of these studies agreed that elements were distributed into the frac-
tions of coal combustion residue (bottom ash, flyash, and vapors) according
to definite patterns. The elements appeared to be divided into three main
classes, as follows.
1. Elements which are approximately equally concentrated in the
bottom ash and flyash.
2. Elements which are enriched in the flyash relative to their
concentrations in the bottom ash.
3. Elements which are primarily discharged to the environment as
gases.
Results from an analytical study conducted at the Tennessee Valley
Authority's Allen Steam Plant2 partitioned elements into the above cate-
gories as shown in Table 2. The elements Cr, Cs, Na, Ni, U, and V were
not placed into one of these three groups but were judged to exhibit
behavior intermediate between the first two groups. Lee^ also found Sb,
Pb, Se, and Zn preferentially concentrated in submicron-sized particles
(Group II) but added Cr to this group as well as Ni, which he found con-
centrated in particles in the 5-10 micron range. Natusch1* agreed that As,
Cd, Pb, Sb, Se, Zn, Cr, and Ni fell into this group of elements showing
pronounced concentration in smaller flyash particles. He placed two other
elements, Tl and S, into this group also. Gordon (Chalk Point Station)5
again placed As, Sb, Pb, and Se in this group and labeled iodine as a
member of the group. Jorden (Valmont Station)6 named As, Sb, Cu, Pb, Mo,
and Zn to the group of elements increasingly enriched with downstream
location. Results from a study of three Northern Great Plains plants7"10
showed that As, Sb, Se, V, Pb, Mo, Ni, B, Zn, Cd, Cr, Cu, Co, U, Ag, S, Hg,
Cl, and F were enriched in the flyash plus flue gas samples, with S, Hg,
Cl appearing to be emitted from the plant as gaseous species. Thus, in
examining just one category, i.e., elements preferentially concentrated in
the flyash, the conclusions of several studies are generally consistent.
This agreement of results is notable, considering the differences in the
furnace types, coal types, and sampling and analytical procedures.
Elements named by one or more studies as primarily emitted to the atmosphere
in the vaporous phase include Cl, F, Br, Hg, S, and Se. Most sulfur is
emitted as S0x and the halogens as hydrogen halides, all of which are
scrubbed in an alkaline SO scrubber (CaO, CaCO , or NaSO ).
x 33
Obtaining representative samples for coal and ash characterization is often
difficult because of variations in coals and complications in stack sampling,
particularly for fine particulate. Comparisons in characterization also are'
impeded by differences in the analytical methods chosen.
8
-------
EABLE 2. PARTITION OF ELEMENTS BY THEIR TENDENCIES FOR
DISTRIBUTION IN COAL COMBUSTION RESIDUES (2)
Group I
Elements Concentrated Approximately Equally in Bottom Ash and Flyash
Al
Ba
Ca
Ce
Co
Eu
Fe
Hf
K
La
Mg
Mn
Kb
Sc
Si
Sm
Sr
Ta
Th
Ti
Group II
Elements Preferentially Concentrated in the Flyash
AsGaSb
Cd Mo S
Cu Fb Zn
Group III
Elements Tending to be Discharged to Atmosphere as Vapors
Hg Cl
Br
-------
The methods used for chemical analysis of coal and ash can be separated
generally into two categories. One category includes methods by which multi-
ple element determinations can be easily made on a single sample. These
methods often do not require sample preparation; analysis may be performed
on the sample directly. Examples of these methods are instrumental neutron
activation analysis, instrumental photon activation analysis, X-ray fluo-
rescence, spark source mass spectrometry, and optical emission spectroscopy.
Methods in the second category usually require considerable sample prepa-
ration for the coal and flyash matrices in order to avoid or reduce inter-
ferences. They may require, too, larger quantities of sample if more than
a few elements are to be determined. These methods include atomic absorption
spectroscopy, potentiometry, voltammetry, and absorption spectrophotometry.
Results from studies which used different methods of analysis may not be
strictly comparable because of differences in performance capabilities among
these methods. In comparing determinations on the same samples by different
laboratories each using several methods, reported concentrations for trace
elements were often found to vary by more than an order of magnitude.
However, a study testing nuclear methods,*1 such as instrumental neutron
activation, photon activation, and natural radioactivity, found their accu-
racy and interlaboratory dispersion generally superior to those of other
methods. Standard samples and standard methods of analysis are needed for
comparable determinations of trace element concentrations in power plant
inlet and effluent streams. A committee of the American Society of Testing
and Materials is presently working to develop standard techniques for coal
and ash analyses.
10
-------
SECTION 5
COAL CHARACTERIZATION
GENERAL
The United States' most widely distributed fuel, coal, is found in 38
states.13 The coals from this wide range of locations include fuels with
extensive variations in heat content, ash content, and chemical properties.
It has been estimated that the coal resources of the United States include
3,968 billion tons with approximately 2,000 billion tons reclaimable using
present technology.13 The cumulative total production of coal is 42.3
billion tons with approximately 21 billion tons produced since 1933. The
utilities industry in 1974 utilized 390 million tons and by 1984 the
industry is expected to use 800 million tons a year.llf
The ASTM classification (ranking) of coals which is commonly used in the
United States is based primarily on the percent volatile matter and calo-
rific values. Figure 1 presents the ranking of coals according to these
factors. Geological and.mining research has shown that coal rank can be
correlated with geological structure and geographical location of the coal
deposits. The geographical locations of U.S. coals (by rank) are shown in
Figure 2.
ORIGIN
The coal fields were formed from ancient peat swamps which were subjected
to intense heat and pressure for millions of years. The temperature and
pressure were accomplished by the deposition of rocks and soils from the
area around the swamps as the swamps subsided. The subsidences were formed
at depths of up to 7,000 meters where a temperature of 200°C and a pressure
of 1,500 kg/cm^ can occur.15 The degree of coalification depends on the
temperature and pressure to which the swamp was subjected. Catastrophic
earth movements which formed the mountains probably formed many of the coal
fields.
The ash content and the trace element concentration, however, are influenced
by the manner in which the subsidence occurs, i.e., whether the subsidence
is a single occurrence or a multioccurrence, in which there are alternate
layers of swamps and overburden. The coal produced from a multioccurrence
subsidence will tend to have a greater ash content, especially when the
coal is used "as mined," unless extreme care is exercised during mining to
prevent the inclusion of the overburden material at the top and the foreign
11
-------
2
8
O
"0
s?
J-22
0
E
1 3I
o
Anthracite
Bituminous
Nonweathering
98
I
Anthracite
It
92 86 78
1
Semi-
anthracite
Ij
Nonogglomerating
6<
1
I, - Metaanthracite
Low-volatile
bituminous
nT
Medium-
volatile
bituminous
> Fixed Carbon,
dry basis
High-volatile A
bituminous
High-volatile B
bituminous
ru
High-vola
Variety 1
Weathering
lile C bituminc
Variety 2
Agglomerating
Nonweathering
us Us
Variety 3
Subbituminous
Llgnitic
Weathering
Subbituminous A
m.
Subbituminous B
Subbituminous C
Consoli-
dated
Lignite
IV,
Uncon soli-
dated
Brown coal
IVt
Nonagglomerating
> 14,000 _,-
h-
0
14,000
13,000
11,000
9,500
8,300
<8,300
Figure I- ASTM classification of coals by rank. Courtesy American Society for Testing 8 Materials. (16)
-------
Anthracite and Semianthrac
Low-volatile bituminous coal
1
1
1
J_
1
1
1
1
^™— — ^
Lignite
Medium and high-volatile bituminous coal
Figure 2. Coal fields of the conterminous United States. (13)
-------
matter at the bottom of the seam. Also, in many cases, the overburden
material during subsidence will form thin layers (1/8- to 1/2-in.) through-
out the coal seam which will be reclaimed with the coal, again causing an
increased ash content.15
There are three means whereby trace elements may be incorporated into the
coal. These methods are the following.
1. Syngenetic - Elements are deposited from surface waters by living
plants or in dead organic matter in swamps prior to coalification.
2. Diagenetic - Elements are introduced into the coal during coalifi-
cation by waters bringing the elements from areas marginal to the
coal deposits or from the consolidating enclosing sediments.
3. Epigenetic - Elements are introduced into the coal after coalifi-
cation and after consolidation of the enclosing sediments by ground
water deriving elements from unconformably overlying rocks and
soils.4
The components of peat have a large potential for trapping many elements;
however, the actual concentrations of trace elements in coal are highly
variable and are, in fact, quite low in some parts of a swamp. For example,
suppose the peat swamp was located in a basin surrounded by hills. The
rocks in the hills were eroded over time by natural processes. During this
process, trace elements were released along with chemically altered mineral
grains and washed by rain and streams down into the basin. Heavy inorganic
metals tended to be trapped in the margins of the swamp. The center of the
coal seam formed from that swamp then tended to contain lower concentrations
of trace elements.15
CHARACTERIZATION
The major elemental components of coal are carbon, hydrogen, oxygen,
nitrogen, and sulfur. Empirical formulas have been found to range from
C75H140°56N2S for a low 8rade Peat to C240H90°4NS for a ni§h grade
anthracite coal.5 These formulas exclude the ash content of the coals,
which ranges from 3 percent to 30 percent. The variations in the coal
formulas and in the ash content can be attributed to the conditions under
which the coalification of peat swamps occurred.
Organic constituents of coals are derived from the decay of plant material,
which consists of vitrinite (the wood parts), sporinite (the waxy coating
of spores and pollen), fusinite (charcoal from forest fires), and micrinite
(origin unknown). Inorganic constituents are derived from the earth's
crustal formations which surround the peat swamps.15
Inorganic chemical constituents of coal can be separated into three major
categories with respect to their relative concentrations in the coal. The
grouping includes major constituents (greater than 1 percent), minor con-
stituents (generally, 0.1 percent to 1 percent), and trace constituents
(less than 0.1 percent). The concentration ranges for the major and minor
-------
elements in coal ash are given in Table 3 for the four main types of coals,
while the concentration ranges for the trace elements are given in Table 4.
The elements listed in Table 4 are of primary interest in this report
because they may be potential health or environmental hazards after they
are discharged into the environment. Furthermore, the Bureau of Mines has
shown that many of these trace elements are concentrated in coals with
respect to their abundance in the earth's crust. The enrichment in coal
ash of a few of these elements can be seen in Table 5 and that part of the
enrichment which may come from the decay of peat is shown as a percentage
of coal ash in Table 6. For example, ash from oak humus is enriched over
ash from fresh oak leaves by a factor of 2 for NiO and by a factor of 14
for GeO .
When characterizing the effluent from a power plant, the percentage of the
chemical elements which are volatilized or released to the environment must
be determined experimentally in all streams leaving the plant; even then,
the results must be used with caution. The wide ranges in concentration of
the elements from a given coal seam or basin (see Table 7) are an indica-
tion of the sizeable variability which may be expected in experimental
results from a power plant. The need for caution in interpreting results
is further illustrated by considering the data from a report by Billings
et al.*7 on a mercury balance for a fossil fuel plant. The study which
they conducted was a 3-day sampling program of the incoming coal (from one
seam) and all discharge streams. They reported that the mercury concentra-
tion in the coal for the three days was 0.7 ppm, 0.1 ppm, and 0.2 ppm,
respectively, and that the quantities of coal used during the corresponding
time period were 8,552 tons; 8,428 tons; and 8,548 tons. If the average
concentration of mercury (.33 ppm) were used to characterize the incoming
coal, the respective daily mercury input would have been 5.64 Ib, 5.56 Ib,
and 5.64 Ib. Instead, on an actual day-to-day basis, the input was 11.97
Ibs, 1.69 Ibs, and 3.42 Ibs. Further, the results of the flue gas vapor
tests indicated that on the first day of the test 9.3 Ibs of mercury was
discharged into the atmosphere, while 2.2 Ibs and 0.98 Ibs were discharged
on the following two days. If the difference between the mercury in the
coal and that in the flue gas vapor is taken as the quantity remaining in
the ash, it would appear that 2.7 Ibs, -0.5 Ibs, and 2.4 Ibs, respectively,
of mercury was contained in the ash. The analysis of the various ash
collection points, however, showed that on all three days there was 0.6 Ibs
total mercury in the ash. Thus, it is important that especial care be
exercised in the sampling arid analysis processes in this type of study.
-------
TABLE 3. VARIATIONS IN COAL ASH COMPOSITION WITH RANK (18)
Rank
Anthracite
Bituminous
SubMtuminous
Lignite
% Si02
U8-68
7-68
17-58
6-UO
* A1203
25-1*
U-39
U-35
U-26
% Fe203
2-10
2-1*
3-19
1-3U
$ no2
1.0- 2
0.5- U
0.6- 2
0.0-0.8
^ CaO
0.2- U
0.7-36
2.2-52
12.U-52
f0 MgO
0.2- 1
0.1- U
0.5- 8
2.8-lfc
^Na20
-
0.2- 3
-
0.2-28
^KgO
-
0.2- It-
-
0.1,1.3
% so3
0.1- 1
0.1-32
3.0-16
8.3-32
% Ash
U-19
3-32
3-16
U-19
-------
TABLE 14. CONCENTRATIONS OF TRACE ELEMENTS IN COAL (5)
Element
Antimony
Arsenic
Barium
Beryllium
Boron
Concn in
whole coal
(ppm)
0.6-1.5
0.1-2.0
<1
0.2-8.9
1.2
0.9
<0.2-0.6
-------
TABLE 1+ (continued). CONCENTRATIONS OF TRACE ELEMENTS IN COAL (5)
Element
Cadmium
Chlorine
(wt $)
Chromium
Cobalt
uoncn in
whole coal
(ppm)
<0.6
0.04-0.7
30-<300
O.M+-0.50
<0.l-65
11.0
-------
TABLE h (continued). CONCENTRATIONS OF TRACE ELEMENTS IN COAL (5)
Element
Copper
Fluorine
Lead
Manganese
Concn in
whole coal
(ppm)
1U-17
3-180
11-28
5-20
11
50-100
5-33
61
15-18
15
1-15
10-22
60-180
9.6
50-120
1-19
110
50-125
50-100
30-1U3
65-120
91
60-70
U2-52
8
39-105
<50. 0-220.0
k-lk
k-lQ
2-36
8-lU
7.U
lt-218
102
k
7
7
1-2
k-7
9-55
25-95
6-181
108
88-101
Source
A
A
A
IE
IE
IE
IE
IW
N
N
SW
SW
SW
SW
A
A
A
IE
IE
IW
IW
N
N
SW
SW
SW
A
A
A
IE
IE
IE
IW
IW
N
N
SW
SW
A
A
IE
IE
IE
IW
N
(continued)
Analytical
method
.
SSMS
AAS/OES
-
-
SSMS-ID
AAS/OES
AAS/OES
AAS/OES
-
-
AAS/OES
SSMS
XRF
-
SSMS
ISE
-
ISE
-
ISE
-
ISE
SSMS
ISE
ISE
—
AAS/OES
SSMS
-
SSMS-ID
AAS/OES
AAS/OES
_
AAS/OES
-
SSMS
AAS/OES
SSMS
NAA
INAA
NAA
NAA
NAA
% Ash
_
-
6.15-18.27
6.8-10.9
-
10.9-11.2
3. 28-16. Ok
25.85
11.29-15.83
-
-
6.56-13.65
-
6
-
-
6.15-18.27
-
3 .28-16. 0*4-
-
25.85
-
11.29-15.83
-
6.56-13.68
3.85-29.60
-
6.15-18.27
-
-
10.9-H.2
3. 28-16. OU
25.85
-
11.29-15.83
™
-
6.56-13.65
6.15-18.27
6.8-17.26
10.9-H.2
3. 28-16. 0^
25.85
11.29-15.83
19
-------
TABLE 4 (continued). CONCENTRATIONS OF TRACE ELEMENTS IN COAL (5)
Element
Manganese
(Cont.)
Mercury
Molybdenum
Nickel
Concn in
whole coal
(ppm)
6-22
10-240
5-200
0.12-0.21
"fc.S-O.J
0.08-0.46
0.16-1.91
0.13
0.170-0.063
0.0^-1.60
0.19
0.18
0.07
0.07-0.09
0.11-0.71*
0.02-0.06
<0.3
0.02-1.20
0.07
0.05-0.38
1.5-5.8
1-5
10
1-11
4.3
10-20
-------
TABLE U (continued). CONCENTRATIONS OF TRACE ELEMENTS IN COAL (5)
Element
Selenium
Tellurium
Thallium
Tin
Titanium
(wt $)
Uranium
Concn in
whole coal
(ppm)
o.ok-o.3
1.3-6.6
2.6-3. k-
O.U-7.7
2.9
0.8
0.5-3.9
1.2-2.3
O.Uo-3.90
1.9
<0.l-O.U
*l-3
0.2
<0. 02-0. 10
2-36
o IL_ Q
< 0 20*"1 ^4-0
0.1-0.9
1-^7
<3-8
1-5
20
<10
0.6-1.6
<5-l5
^-35
<2-8
0.02-0.18
0.06-0.15
0.05-0.17
0.07
0.02-0.15
0.08
0.06
0.05-0.09
0.03-0.13
0.3-1.0
0.09-3.70
Source
A
A
IE
IE
IW
N
SW
SW
SW
SW
A
IE
SW
SW
A
IE
SW
A
A
A
IE
IE
IE
IW
IW
N
SW
SW
A
A
IE
IE
IE
IW
N
SW
SW
A
SW
Analytical
method
SSMS
NAA
INAA
NAA
NAA
NAA
-
NAA
XRF
XRF
SSMS
SSMS
SSMS
we
SSMS
INAA
AAS
H
SSMS
OES
-
SSMS
OES
OES
_
OES
SSMS
OES
SSMS
XRF
NAA
XRF
XRF
XRF
SSMS
XRF
SSMS
INAA
% Ash
.
6.15-18.27
10.9-11.2
3. 28-16. Oh
25.85
11.29-15.83
-
6.58-13.68
3.85-29.60
6
_
10.9-11.2
-
3.85-29.60
_
10.9-11.2
3.85-29.60
-
-
6.15-18.27
-
10.9-11.2
3. 28-16. Ok
25.85
-
11.29-15.83
-
6.56-13.68
6.15-18.27
6.8-17.26
10.9
3.28-16.0^
25.85
11.29-15.83
6.56-13.68
3.85-29.60
(continued)
21
-------
TABLE k (continued). CONCENTRATIONS OF TRACE ELEMENTS IN COAL (5)
Concn in
whole coal
Element (ppm)
Vanadium 19-25
3-77
2^-52
35
21-69
16-78
1+0
1^-18
11-26
2-8
10-22.5
17-22
Zinc k.k-12
3-80
21-ltO
118-
-------
TABLE ^ (continued). CONCENTRATIONS OF TRACE ELEMENTS IN COAL (5)
b. Abbreviations for analytical methods
AAS = Atomic Absorption Spectroscopy
AS = Absorption Spectroscopy
FAAS = Flameless Atomic Absorption Spectroscopy
GC-MES = Gas Chromatography with Microwave Emission
Spectroscopic Detection
INAA = Instrumental Neutron Activation Analysis
ISE = Ion-Selective Electrodes
KAA = Neutron Activation with Radiochemical Separation
OES = Optical Emission Spectroscopy-Detection
Method Unspecified
OES-DR = Optical Emission Spectroscopy with Direct
Reading Detection
OES-P = Optical Emission Spectroscopy with
Photographic Detection
PAA = Photon Activation Analysis
PES = Plasma Emission Spectroscopy
SSMS = Spark Source Mass Spectroscopy
SSMS-ID = Spark Source Mass Spectroscopy with
Isotope Dilution
WC = Wet Chemistry
XRF = X-Ray Fluorescence Spectroscopy
23
-------
TABLE 5. TRACE ELEMENTS IN ASHES OF COAL AND IN THE EARTH'S CRUST (19)
Element
Beryllium
Boron. .........
Cobalt
Nickel
Zinc
Gallium. .......
Yttrium
Tin
Silver
Gold
Symbol
Be
B
Sc
Co
Ni
.Zn
Ga
Ge
As
Y
Zr
Mo
Sb
Sn
Pb
Bi
Ag
Au
Rh
Pd
Pt
Maximum Average Percentage in
percentage percentage earth's crust
in coal ashes of "rich" ashes
0.1
0.3
0.0!*
0.15
0.8
1.
O.OU
1.1
0.8
0.08
0.5
0.05
0.1
0.05
0.1
0.003
0.0005 to 0.001
0.00002 to 0.00005
0.000002
0.00002
0.00007
0.03
.06
.006
.03
.07
.01
.05
.05
.01
.02
.02
.02
.0002
0.0002 to 0.001
0 . 0003
0.0003 to 0.0006
O.OOU
0.01
0.02
0.001 to 0.0015
0. 000*4 to 0.0007
0.0005
0.001
0.02
0.0015
0.005
0.0016
0.00001
0.0000005
Factor or enrichment
Maximum in
coal ashes
100 to 500
1,000
70 to 130
1*0
80
50
30 to UO
1,600 to 2,800
1,600
80
25
30
10
70
50 to 100
UO to 100
Average of
"rich" ashes
30 to
200
10 to
8
7
7 to
70 to
100
10
13
U
20
150
20
10
120
-------
to
Ui
TABLE 6. ENRICHMENT OF ELEMENTS DURING DECAY OF OAK AND BEECH HUMUS; PERCENT OF ASH (19)
Mineral soil
Ash
Ash
Ash
from
from
from
(sand)
fresh oak leaves
oak
humus
"beech humus
0
0
0
0
B20-,
.0007
.5 to 1.0
.02
.003
MnO
0.0^
2.00a
0.2k
O.lU
0
0
0
0
NiO
.002
.005
.01
.01
0
0
0
0
Ge02
.0005
.0005
.007
.007
AspOs Ag Au
_
_
0.0001
0.05 0.0005 0.00002
Q
Ash from fresh beech leaves; in weathered leaves from previous year, 0.77 percent MnO.
-------
TA.BLE 7. QUANTITATIVE ANALYSES (in ppm) FOR 13 TRACE ELEMENTS IN DRILL-CORE COAL SAMPLES, POWDER RIVER
BASIN.(Blank space indicates analysis not completed at time of report preparation. (20)
ro
Sample
interval
(ft)
100-109
109-112
240-247
231-232
116-127
127-137
137-140
100-104
60-68
166-176
108-118
216-226
71-72
80-88
88-98
143-150
92-101
101-106
140-147
100-110
110-120
Drill-core
sample
no.
458
459
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
ppm, coal
As
2.
2.
2.
3.
1.
1.
3-
2.
2.
2.
3.
4.
5-
3.
2.
3.
5-
3.
4.
4.
3-
F
4o
30
10
10
30
20
30
30
60
1C
Hg
0.035
0.082
0.037
0.051
0.044
0.030
0.106
0.035
0.049
0.099
0.043
0.065
0.039
0.035
0.021
0.058
0.181
o.o48
0.028
o.o4i
0.035
Sb
0.92
0.62
0.08
0.12
0.04
o.o4
0.06
0.08
o.o4
<0.04
Se
<0.1
0.4
<0.1
<0.1
0.2
<0.1
0.6
<0.1
0.5
0.2
0.6
0.5
0.9
0.5
0.3
1.0
1.5
0.5
0.6
1.2
0.3
Te
0.1
0.1
<0.02
0.02
<0.02
<0.02
<0.02
<0.02
0.1
0.05
T)
aj
a
£
d)
-p
-------
TABLE 7. QUANTITATIVE ANALYSES (in ppm) FOR 13 TRACE ELEMENTS IN DRILL-CORE COAL SAMPLES, POWDER RIVER BASIN
(20) (continued) (Blank space indicates analysis not completed at time of report preparation.)
to
Sample
interval
(ft)
100-109
109-112
2UO-2U7
231-232
116-127
127-137
137-1^0
100 -10U
60-68
166-176
108-118
216-226
71-72
80-88
88-98
1U3-150
92-101
101-106
1UO-1U7
1CD-110
110-120
Drill-core
sample
no.
1*58
1459
k62
1+63
U6U
1*65
U66
46?
M58
U69
k70
U71
*472
1473
U71)-
^75
14-76
U77
U78
1479
U8o
ppm, ash
Cd Cu
335
1.5 385
<1.0 U20
4.
232
22^
Ash
p7
fO
3.20
6.80
3.25
U.56
U.56
3.^3
7.12
6.92
8.16
U.87
8.08
7.30
6.U2
8.2^
5.^0
6.20
11.3
5.67
5.00
111. 8
6.52
-------
SECTION 6
PHYSICAL CHARACTERIZATION OF ASH
GENERAL
The ash residue resulting from the combustion of coal is primarily derived
from the inorganic mineral matter in the coal. As Table 3 shows, different
types (rank) of coal produce different quantities of ash, depending on the
concentration of mineral matter in that type of coal. Generally, ash makes
up from 3 to 30 percent of the coal.
During the combustion of coal, the products formed are partitioned into three
categories—bottom ash, flyash, and vapors. The bottom ash is that part of
the residue which is fused into particles heavy enough to drop out of the
furnace gas stream (air and combustion gases). These particles are collected
in the bottom of the furnace. The flyash is that part of the ash which is
entrained in the combustion gas leaving the boiler. While most of this
flyash is collected in either mechanical collectors and/or electrostatic
precipitators, a small quantity of this material may pass through the col-
lectors and be discharged into the atmosphere. The vapor is that part of
the coal material which is volatilized during combustion. Some of these
vapors are discharged into the atmosphere; others condense onto the surface
of flyash particles and may be collected in one of the flyash collectors.
For the majority of elements found in coal, most of their quantity (95 per-
cent or more) will be found in the ash fractions, while the remainder (5
percent or less) will be discharged into the atmosphere.2 The quantity of
vapors produced depends primarily on the temperature history of the combus-
tion gases and the concentrations and properties of the various elements in
the coal.
The distribution of the ash between the bottom ash and flyash fractions is
a function of the burner type, the type of coal (ash fusion temperature),
and the type of boiler bottom (wet or dry). The first factor, burner type,
is especially significant in determining the distribution. The different
methods of firing pulverized-coal boilers are shown in Figure 3, while
Table 8 presents the relative distribution of bottom ash and flyash by
boiler firing method. Stoker fired units emit the smallest proportion of
flyash, and this flyash is relatively coarse. In a cyclone unit the melt-
ing point for the ash is exceeded, and 80-85 percent of the ash is then
melted and collected as slag. The small quantity of flyash which a cyclone
unit produces is usually composed of very fine particles (90 percent is
smaller than 10 ym in diameter).12 Pulverized coal units usually produce
28
-------
Primary air—| | Tertiary air
and coal
Primary air
and coal
, Second
Fantail
"to\
1\W /
Multiple
tntertube
(A.) VERTICAL FIRING
Primary air
and coal
\ AV ^
nf
v\
Plan View of Furnace
Primary air
and coal
Secondary
air
(B.) TANGENTIAL FIRING
Primary air
and coal
Secondary air
Multiple Intertube
Secondary air
Circular (c.) HORIZONTAL FIRING
Secondary air
Primary air
and coal
Cyclone
(D.) CYCLONE FIRING
Secondary air
Primary air
and coal
(E.) OPPOSED-INCLINED FIRING
Figure 3. Pulverized-coal firing methods. (24)
-------
TABLE 8. COMPARISON OF DISTRIBUTION BETWEEN BOTTOM ASH AND FLYASH
BY TYPE OF BOILERS AND METHOD OF FIRING (21)
Wet (W) or dry (D)
bottom boiler
¥
W
W
D
D
D
-
-
Type of firing^
PCFR
PCOP
PCTA
PCFR
PCOP
PCTA
CYCL
SPRE
%
Bottom Ash
(typical)
35
35
35
15
15
15
90
35
%
Fly Ash
(typical)
65
65
65
85
85
85
10
65
aPCFR - Pulverized coal front firing
PCOP - Pulverized coal opposed firing
PCTA - Pulverized coal tangential firing
CYCL - Cyclone
SPRE - Spreader stoker
30
-------
65 to 80 percent flyash21 and 20 to 35 percent bottom ash. The second
factor, ash fusion temperature, is important in that ashes with lower fusion
temperatures tend to be melted within the boiler and collected as bottom
ash. Finally, wet bottom boilers are designed to produce and process a much
larger proportion of bottom ash than are dry bottom boilers.
The ashes vary in size as they are discharged from the furnace from less
than one y to 4 cm in diameter. The flyash fraction generally consists of
fine spherical particulates usually ranging in diameter from 0.5 y to
100 y.12'22 This fraction spans a color range of light tan to gray to black.
Increased carbon content causes a darker gray-black tone, while increased
iron content tends to produce a tan-colored ash. The pH of flyash contacted
with water may vary from 3 to 12, with the pH for the majority of pulverized
coal-burned flyashes contacted with water ranging from 8 to 12.23
Cenospheres, which are very lightweight particles that float on ash pond
surfaces, are an interesting fraction of the flyash. These are silicate
glass spheres filled with nitrogen and carbon dioxide 'which vary from 20 y
to 200 y in diameter. Particle density ranges from 0.4 g/cc to 0.8 g/cc.
These particles may comprise as much as 5 percent by weight or 20 percent
by volume of the flyash.12
The bottom ash fraction of coal combustion residue is collected in either
the ash or the slag form, depending on whether the boiler is a wet bottom
or dry bottom design. Dry bottom boilers produce ash, which is composed
usually of gray to black, angular particles with porous surfaces. Wet bottom
boilers produce slag, which generally consists of angular black particles
with a glassy appearance. A comparison of the grain size distribution curves
for several bottom ash and flyash samples from pulverized coal units is
given in Figure 4. These samples were taken from Fort Martin Unit 1
(tangentially-fired) and Unit 2 (wall-fired). These bottom ashes range from
about 0.07 mm to 40 mm in diameter and the flyashes from 0.0015 mm to 0.45 mm
in diameter.
For the collected flyash, particle size distribution and total surface area
vary depending on the types of collector employed. A comparison of the par-
ticle size distribution of flyash collected in an electrostatic precipitator
and that collected in a mechanical collector is shown in Figure 5. The ash
collected by electrostatic precipitators contains a much greater percentage
of the very small particles (<1.5y). However, as the size of the particles
approaches the 150 y diameter, the percentages of ash collected by the two
methods are approximately equal.25
The reliability of particle size distribution data also depends on the method
employed to determine particle size. For example, data in Table 9 is a com-
parison between three methods (microscope count, turbidimeter, and hydro-
meter) . Results from both the turbidimeter and the hydrometer indicate that
the flyash contained a much lower percentage of the very fine particles than
do the results of the microscope count method. The apparent low percentage
of fine particles when analyzed by the turbidimeter and hydrometer was due
to large differences in the specific gravity of the particles. The small
31
-------
U.S. Standard Sieve Opening in Inches U.S. Standard Sieve Numbers
Hydrometer
N>
e
«
o
6 4 3 2 11/2 1 3/4 1/2 3/83 46 8 10 14 16 203040 50 70 100 140200
art
-------
100-
90-
80-
70-
60-
S.
0>
>
^ 40- -
30- -
20- -
E.S.P. Ash
Mechanical Collector
I 10
Particle Size, Micron N
Figure 5. Particle size distribution of flyash. (26)
100
1000
-------
IABLE 9 • COMPARISON OF PARTICLE SIZE DISTRIBUTION BY THREE METHODS OF DETERMINATION (26)
Cumulative percentage by weight finer than
Microscope
Size Count
ju MC ESP
2380
1190
590
297
lU9
7U
60
^5
38
30
23
15
10
5
3.
1.5
100.0
99.9
99-5
98.8
97-5
88.0
81.6
72.3
68.2
57.9
51. U
U8.7
37.6
16.9
7.3
2.7
—
100.0
99. ^
98,0
93.7
91.3
87.7
85. k
80.2
79-0
78.3
76.0
67.0
55.6
32.7
Turbidimeter
Size
M MC ESP
60
55
50
^5
to
35
30
25
20
15
10
7.5
80.6
76.1
71.5
67.6
61.6
5^.9
U6.3
36.0
2h.9
ll+.O
U.8
1.1
91.2
89.5
87.9
85.6
82.2
79-3
73.1
6U.9
51.6
33.9
2U.6
15.2
Hydrometer
M.C. ESP
Size u Percent Size u Percent
58 90.0 59 9^-1
U3 8l.O U2 90.0
33 70.5 31 83. U
25 59-0 23 7^.2
15 12.0 lU 13.8
12 3.U 11 10.8
7.5 8.3
—
M3 - Mechanical Collector
ESP - Electrostatic Precipitator
-------
particles with higher specific gravities tended to settle out very fast,
indicating that they were much larger in size.26 The different results
sometimes obtained using different methods, indicate the need for improve-
ment and standardization of methods for determining particle size.
COMPARISON OF ASH FROM A MECHANICAL COLLECTOR AND ELECTROSTATIC PRECIPITATOR
While it is recognized that all flyashes vary to some degree in their
physical properties, the following description of two ashes (one collected
by a mechanical collector and the other by an electrostatic precipitator)
may illustrate the general or typical characteristics. These ashes were
studied26 by dividing the samples roughly into three fractions—coarse,
medium, and fine—through the use of a mechanical air separator. Each of
these fractions was then subjected to both physical and chemical analyses.
The results of the sieve analysis of the samples are given in Tables 10 and
11. The percentage of material finer than the No. 325 sieve is higher for
the ash collected by the electrostatic precipitator than for the mechanic-
ally collected ash in all three size fractions. For the medium and fine
fractions, the percentage of material retained on all sieves is higher for
the mechanically collected ash than for the ash collected by the electro-
static precipitator. This is also true for the coarse fraction, except for
the material retained on sieves No. 270 and 325.
The fineness (by three different methods) and the specific gravity of the
three fractions are given in Table 12. The results of these tests indicate
that coarser materials have higher specific gravities for both types of
collection devices.
Table 13 presents the results of the chemical analysis for the physically
size-differentiated fractions. The major differences noted in this analysis
are as follows.26
1. The lithophile materials (alumino-silicates) were more concentrated
in the finer fractions.
2. The magnetite-hematite materials (iron-bearing) were more concen-
trated in the coarser fractions.
3. The alkalies (Na and K) were generally more concentrated in the
finer fractions. (This occurrence is probably because of their
association with the lithophiles.)
4. The higher loss on ignition occurred in the finer fraction.
Representative samples of the ash were sieved across sieves Nos. 200, 325,
400, and 500. The fraction of each sample of flyash retained on each sieve
was then subjected to petrographic analysis. The results of this analysis
are shown in Table 14.
The glass constituent, which was the most abundant component in both samples,
was more concentrated in the electrostatic precipitator ash. Also, the finer
materials included a higher percentage of glass, with the material passing
35
-------
TABLE -10. PARTICLE SIZE DISTRIBUTION OF ASH FROM A MECHANICAL COLLECTOR (26)
OJ
Particle Size Distribution (Tyler), % by Weight
Classi- Weight
fication Ib %
Coarse 6.5 3.7
Medium 47.5 27.0
Fine 122.0 69.3
Re-
tained
on
No. 48
Sieve
17.8
0
0
Pass-
ing
No. 48
Re-
tained
on
No. 65
6.3
0
0
Pass-
ing
No. 65
Re-
tained
on
No. 100
12.0
0.9
0
Pass-
ing
No. 100
Re-
tained
on
No. 150
17.3
3.8
0.2
Pass-
ing
No. 150
Re-
tained
on
No. 200
24.0
13.0
0.6
Pass-
ing
No. 200
Re-
tained
on
No. 270
13-9
19.6
1.4
Pass-
ing
No. 270
Re-
tained
on
Wo. 325
6.5
27.9
4.4
Finer
than
No.
325
Sieve
2.2
34.8
93.4
-------
TABLE 11. PARTICLE SIZE DISTRIBUTION OF ASH FROM AN ELECTROSTATIC PRECIPITATOR (26)
u>
-vl
Particle Size Distribution (Tyler), % by Weight
Classi-
fication
Coarse
Medium
Fine
Weight
Ib %
11.5 1.9
52.0 8.7
53^.0 89. k
Re-
tained
on
No. If 8
Sieve
7-5
0.3
0
Pass-
ing
No. kQ
Re-
tained
on
No. 65
2.9
0.3
0
Pass-
ing
No. 65
Re-
tained
on
No. 100
7.5
1.2
0
Pass-
ing
No. 100
Re-
tained
on
No. 150
9A
2.8
0.1
Pass-
ing
No. 150
Re-
tained
on
No. 200
23.8
10.0
0.2
Pass-
ing
No. 200
Re-
tained
on
No. 270
16.5
15.1
0.5
Pass-
ing
Wo. 270
Re-
tained
on
No. 325
15.2
19-7
1.2
Finer
than
No.
325
Sieve
17.2
50.6
98.0
-------
TABLE 12. SURFACE AREA BY THREE METHODS (26)
oo
Test Method
Air Permeability
Turbidemeter
Hydrometer
Specific Gravity
Results
Obtained
IN
sq cm/g
sq cm/g
sq cm/g
MECHANICAL
As Re-
ceived
1167
720
1079
Fine
2457
1110
2266
2.47
COLLECTED ASH
Processed
Medium
709
290
790
2.60
Coarse
ta8
90
370
2.92
As Re-
ceived
3480
1570
3126
ESP COLLECTED ASH
Processed
Fine Medium
4215 1150
2010 875
4039 1216
2.53 2.64
Coarse
611
215
848
3.02
-------
TABLE 13. CHEMICAL ANALYSIS (26)
VD
MECHANICAL COLLECTED
FLY ASH
Test Result
si02,?0
A1203,%
Fe203,?0
CaO,f0
MgO,
-------
TABLE 14. PHASE COMPOSITION (26)
ESP COLLECTOR
Percentage Retained
on Sieves*
Constituent
Glass
Magnet ite -hematite
Carbon
Anisotropic material
Aggregates
Total
Wo.
200
32
2
33
27
6
100
No.
325
^9
Ik
8
22
7
100
No.
400
52
13
9
18
8
100
No.
500
56
14
5
15
10
100
Pass-
ing
No.
500
87
5
1
3
4
100
Compo-
sition
of
Whole
Sample
%**
79
6
4
6
5
100
MECHANICAL COLLECTOR
Percentage Retained
on Sieves*
No.
200
35
8
47
3
7
100
No.
325
55
5
29
3
8
100
No.
400
61
20
7
3
9
100
No.
500
58
26
8
3
5
100
Pass-
ing
No.
500
63
16
5
5
11
100
Compo-
sition
of
Whole
Sample
%**
58
16
13
4
9
100
*Percentage is based on count of more than 300 particles in each sieve fraction.
**Percentage is based on gradation of as-received sample and on the distribution of constituents
of wet sieved fractions.
-------
the 500 mesh sieve containing the highest percentage of glass. "The glass
consisted of colorless to light green and amber spheres, broken hollow
spheres, ellipsoids, and teardrop—and irregularly shaped particles. Many
contained inclusions of iron oxide, birefringent material, and small
bubbles."15 The birefringent material, which refracts light in two slightly
different directions, was probably mullite in this case, since this mineral
was identified by X-ray diffraction.
The magnetite-hematite material was more concentrated in the ash from the
mechanical collector than it was in ash collected from the electrostatic
precipitator. In both ashes, this material was the second most abundant
constituent. These particles are spherically-shaped and have the charac-
teristic of appearing opaque in transmitted light while exhibiting a gray
metallic luster in reflected light. Magnetite-hematite particles may also
be found as small opaque inclusions in the glass particles. In the 1-20
micron range, a few bright red hematite particles were observed.26
The carbon particles had varied shapes with the predominant shape being
highly irregular cellular particles. These particles increased in abundance
as the particle size increased. The carbon particles in the coarser ash had
a cinder-like appearance and were magnetic due to particles of magnetite
and hematite lodged in the cellular structure of their walls. The original
woody structure was observed in a few particles.16
The anisotropic material was a low birefringent substance enclosed in glass
particles and quartz in a well-crystallized state. The low birefringent
material was a mixture of mullite and devitrified glass. In the finer ash,
highly carbonated portland cement was found to be a contaminant of aniso-
tropic material.26
The aggregates of glass, magnetite, hematite, and carbon particles were
present in all size ranges. A few of these particles appeared to be fused,
but the majority of them were very loosely held together. X-ray diffraction
studies showed that the crystalline constituents were magnetite, hematite,
quartz, mullite, portland cement, and traces of anhydrite (CaSO ).26
-------
SECTION 7
CHEMICAL CHARACTERIZATION OF ASH
CHEMICAL COMPOSITION BY COAL RANK AND BY ASH FRACTION
The chemical composition of coal ash depends largely on the geologic and geo-
graphic factors related to the coal deposit, the combustion conditions, and
the removal efficiency of air pollution control devices. The inorganic con-
stituents of ash are those typical of rocks and soils, primarily Si, Al, Fe,
and Ca; the oxides of these four elements comprise 95 percent to 99 percent
of the composition of ash. Ash also contains smaller amounts (0.5 percent -
3.5 percent) of Mg, Ti, S, Na, and K as well as very small quantities (parts
per million) of from twenty to fifty elements.
One must use caution in attempting to characterize the effluents from a power
plant based on the average ash analysis from coal of any given rank. As
Table 15 illustrates, the maximums and minimums of some trace elements
exhibit great variability within ashes from coals of the same rank. These
values are from atomic absorption analyses of coals ashed in air at 600°C.
Analysis of various ashes shows that the distribution of major elements is
approximately the same in the bottom ash and flyash fractions. However,
for certain of the trace components, there is a very definite partitioning
between the bottom ash and flyash. Table 16 shows that for some elements
there can be differences of an order of magnitude in the concentrations of
trace elements between these two fractions; for example, Se exhibits this
tendency.
Results from several plants on the concentrations of trace elements in fly-
ash or flue gas are shown in Table 17. The source of the coal, the control
method, and the method used for analysis of the element are given whenever
available.
ANALYTICAL STUDIES
The quantities of potentially hazardous pollutants entering the environment
as the result of coal combustion increase with the steady growth in amount
of coal being utilized. A lack of information concerning the trace consti-
tuents of coal during and after combustion has coupled with increased know-
ledge of possible pollutant effects to heighten awareness of this problem.
-------
TABLE 15. RANGE IN AMOUNT OF TRACE ELEMENTS PRESENT IN COAL ASHES (27)
(ppm)
Anthracites
Element
Ag
B
Ba
Be
Co
Cr
Cu
Ga
Ge
La
Mn
Ni
Fb
Sc
Sn
Sr
V
Y
Yb
Zn
Zr
Max.
1
130
13^0
11
165
395
5to
71
20
220
365
320
120
82
1*250
3l*0
310
120
12
350
1200
Min.
1
63
51*0
6
10
210
96
30
20
115
58
125
in
50
19
80
210
70
5
155
370
Aver age (5)
*
90
866
9
810
30*4.
1*05
1*2
•*
ll*2
270
220
81
61
962
177
21*8
106
8
*
688
High volatile
Max.
3
2800
U660
60
305
315
770
98
285
270
700
610
1500
78
825
9600
81*0
285
15
1200
11*50
Min.
1
90
210
i*
12
71*
30
17
20
29
31
^5
32
7
10
170
60
29
3
50
U-5
bituminous
Average (2VJ
*
770
1253
17
&i
193
293
Uo
*•
111
170
15^
183
32
171(22)
1987
214-9
102
10
310 @
1*11
* = Insufficient figures to compute an average value.
0 = Figures encircled indicate the number of samples used to compute average values.
(continued)
43
-------
TABLE 15. RANGE IN AMOUNT OF TRACE ELEMENTS PRESENT IN COAL ASHES (27)
(continued) (ppm)
Low
Element
Ag
B
Ba
Be
Co
Cr
Cu
Ga
Ge
La
Mn
Hi
Pb
Sc
Sn
Sr
V
Y
Yb
Zn
Zr
Volatile
Max.
1.1*
180
2700
1*0
1*1*0
1*90
850
135
20
180
780
350
170
155
230
2500
1*80
1*60
23
550
620
Bituminous
Min.
1
76
96
6
26
120
76
10
20
56
1*0
61
23
15
10
66
115
37
I*
62
220
Average (8)
*
123
71+0
16
172
221
379
1*1©
#
110
280
11*1
89
50
92©
818
278
152
10
231
1*58
Medium
Max.
1
780
1800
31
290
230
560
52
20
ll*0
1*1*00
1*1*0
210
110
160
1600
860
31*0
13
i*6o
51*0
Volatile
Min.
1
7U
230
1*
10
36
130
10
20
19
125
20
52
7
29
1*0
170
37
1*
50
180
Bituminous
Average (T)
*
218
896
13
105©
169
313
*
*
83
11*32
263(6)
96
56
75
668
390
151
9
195(6)
326
* = Insufficient figures to compute an average value
0 = Figures encircled indicate the number of samples"used to
average value.
(continued)
compute an
44
-------
TABLE 15, RANGE IN AMOUNT OF SEACE ELEMENTS PRESENT IN COAL ASHES (2?)
(continued) (ppm)
Lignites and Subbituminous
Element
Ag
B
Ba
Be
Co
Cr
Cu
Ga
Ge
La
Mn
Ni
Fb
Sc
Sn
Sr
V
Y
Yb
Zn
Zr
Max.
50
1900
13900
28
310
lUo
3020
30
100
90
1030
1*20
165
58
660
8000
250
120
10
320
1*90
Min.
1
320
550
1
11
11
58
10
20
31*
310
20
20
2
10
230
20
21
2
50
100
Average (Q
*
1020
5027
6
1*5
&
655
23 (ill
*
62
688
129 8
60
18 @
156
1*660
125
51
1*
#
2l*5
*=Insufficient figures to compute an average value.
0 =Figures encircled indicate the number of samples used to
compute average values.
45
-------
TABLE 16. COMPARISON OP FLY ASH AND BOTTOM ASH FROM VARIOUS UTILIIY PLAH3S (2,28,29,30)
Compound
or
Element
sio2,*
AW*
Fe2°3 A
CaO,$
so3,$
t*fecO %
ilQi—0 JQ
K2o,#
P2°5#
Ti°2#
As ,ppm
Be ,ppm
Cd,ppm
Cr,ppm
Cu,ppm
Hg.ppm
Mn,ppm
Ni,ppm
Pbjppm
Se,ppm
V ,ppm
Zn,ppm
B ,ppm
F ,ppm
Plant
FA
59.
27.
3.8
3.8
0.1*
0.96
1.88
0.9
0.13
0.1*3
12.
1*.3
0.5
20.
5k-
0.07
267.
10.
70.
6.9
90.
63.
266.
7.
11*0.
1(30)
BA
58.
25-
i*.o
M
0-3
Plant 2(30) Plant
FA
57.
20-
5.8
5.7
0.8
0.88 1.15
1.77 1.61
0.8
0.06
1.1
o.oi*
0.62 1.17
1.
3.
0.5
15-
37.
0.01
366.
10.
27.
0.2
70.
21*.
1>*3.
7-
50.
8.
7.
0.5
50.
128.
0.01
M. -FA.
59. ^3.
18.5 21-
9.0 5.6
l*.8 17.0
0.3 1.7
0.92 2.23
1.01 1.1*1*
1.0 0.1*
0.05 0.70
0.67 1.17
1. 15.
7. 3..
0.5 0.5
30 . 150.
1*8 . 69 .
0.01 0.03
3(30)
-BA.
50.
17-
5.5
13-0
0.5
1.6:
Plant
JA,
28-
3.1*
3.7
0.1*
. 1.29
0.61* 0.38
0.5
1.5
0.30 i.oo
0.50 0.83
3.
2 .
0.5
70.
33-
0.01
150. 700. 150. 150.
50.
30.
7.9
150.
50.
22. 70.
30. 30.
0.7 18.0
85. 150.
30. 71.
200. 125. 300.
20.
100.
15-
20.
1.0
70.
27.
70.
12 . 15 . 7.
50. 610. 100.
6.
7 .
1.0
30.
75-
0.08
1*(30) Plant 5(29)
_BA_
59.
21*.
3.3
3.5
0.1
1.17
0.1*3
1.5
0.75
PA
NR
NR
20.
3.
NR
NR
NR
NR
NR
0.50 NR
2-
5.
1.0
30.
1*0.
0.01
100. 100.
20.
70.
12.0
100.
103.
10.
30.
1.0
70. ;
8A
8.0
6.1*1*
206.
68.
20.0
21*9.
131*.
32.
26.5
3U1.
^5. 352.
700. 300.
15.
250.
7.
85.
NR
6.0
621*.
-BA.
NR
NR
U 30.
2 1*.
Plant
TO
1*2.
17.
1* 17.3
9 3.5
0.1* NR
NR
NR
NR
NR
NR
5.8
7.3
1.08
121*.
1*8-
0.51
229.
62.
8.1
5.6
353.
150.
NR
3.6
10.6
1.76
1.36
2.1*
NR
1.00
110-
NR
8.0
300.
11*0-
0.05
298.
207.
80.
25.
6(2,28)
-HA.
19.
l£.o
6.1*
NR
2.06
0.67
1-9
NR
0.68
18-
NR
1.1
152.
20-
0.028
295-
85-
6.2
0,08
^1*0. 260.
71*0. 100.
NR
NR
39. 20.8
NR NR
46
-------
TABLE 17. CONCENTRATIONS OF TRACE ELEMENTS IN COAL PLY ASH AND FLUE GA.S (5)
(ppm)
Concn in Concn suspended
fly ash in flue gas
Element
Antimony
Arsenic
Barium
Beryllium
Boron
Bromine
Cadmium
Chlorine
Concn in
coal
<700
.
-
0.72-lA
_
-
0.5
5.1*
_
_
_
20-32
_
_
Ik
—
<300
130-210
59
—
<2
.
<5
100-200
32-^5
_
6
0.1.6
355-^07
a.
Source
A
IE
IE
IE
-
SW
sw
IE
Av U.S.
A
A
IE
_
SW
sw
IE
A
IE
_
IE
A
IE
IE
IE
A
IE
-
A
IE
IE
IE
IE
IE
Control
method0
ESP
Mech
ESP
cy
ESP
ESP
WS
ESP
—
ESP
ESP
Cy
ESP
ESP
WS
ESP
ESP
Meeh
ESP
ESP
ESP
Mech
Cy
ESP
ESP
ESP
ESP
ESP
ESP
Mech
ESP
cy
ESP
ESP
Before
control
<6oo
-
-
-
-
lk
12
_
-
-
_
-
.
130
120
_
-------
TABLE 17. (continued). CONCENTRATIONS OF TRACE ELEMENTS IN COAL FLY ASH AMD FLUE GAS (5)
(ppm)
Conon in Concn suspended
fly ash in flue gas
Element
Chromium
Cobalt
Copper
Fluorine
Iodine
Lead
Manganese
Mercury
Concn in
coal
20
-
-
25-35
20
_
0
_
It. 9-6. 2
3.0
_
20
-
9.6
9.6
50-100
<2-60
25-64
-
<30
-
6.5-12.4
-
-
4.9
-
90
31-^5
34
0.11 0.63
0.11-0.63
0.33
<2
0.122
Q
Source
A
IE
IE
IE
-
IE
A
IE
IE
-
IE
A
IE
IE
SW
SW
IE
-
-
A
IE
IE
-
SW
SW
IE
-
A
IE
IE
IE
SE
SE
A
IE
IE
Control
method
ESP
Mech
ESP
Cy
ESP
ESP
ESP
Mech
Cy
ESP
ESP
ESP
Mech
Cy
ESP
WS
ESP
-
ESP
ESP
Mech
Cy
ESP
ESP
WS
ESP
ESP
ESP
Mech
cy
ESP
ESP
Mechd
ESP
ESP
ESP
Mech
ESP
Before
control
500
-
-
-
310
_
60
_
_
in
_
100
-
_
280
300-400
< 10-100
-
_
200
-
-
-
110
80
_
500
290
<0.2
0.05
After Before
control control
1674
7400
300
290-3300
-
900
227
70
60-130
-
65
620
200
270-390
320
290
200-400
-
-
649
200
1100-1600
— _
130
34o
650
1+65
1362
800
150-470
430
o'k I
89
20
After
control
20
-
0.7
-
13.8+5.1
-
20
_
_
3.4+2.1
-
48
_
_
_
_
-
-
28.3±3.l
91*
—
13.8±2.8
—
—
-
23
25±13
62
1*3
31
15
Analytical
method
OES-P
-
FAAS
AAS
INAA
INAA
OES-P
_
OES
INAA
INAA
OES-P
_
SSMS
XBF
XEF
SSMS
SSMS
INAA
OES-P
_
AAS
PAA
XEF
XRF
SSMS -ID
OES
OES-P
OES
INAA
INAA
FASS
FASS
INAA/ASV/PES
OES-P
TOSS
(continued)
48
-------
TABLE 17 (continued). CONCENTRATIONS OP TRACE ELEMENTS IN COAL FLY ASH AND FLUE GAS(5)
(ppm)
Concn in Concn suspended
Element
Molybdenum
Nickel
Selenium
Tellurium
Thallium
Tin
Titanium
Concn in
coal
_
<20
0.99
0.99
3.6
10-30
-
90
_
-
21-1*2
< 100-150
<6oo
_
-
2.8-7.8
1.9
1.9
2.2
1-3
<100
_
2
<700
_
20
<98o
_
900-11*50
510
Sourcea
A
IE
SW
SW
IE
_
A
IE
IE
IE
-
IE
IE
IE
IE
_
SW
SW
IE
IE
IE
IE
IE
A
IE
IE
IE
A
IE
IE
IE
IE
Control
method
ESP
Mech
ESP
WS
ESP
ESP
-
Mech
ESP
cy
ESP
ESP
Mech
ESP
cy
ESP
ESP
WS
ESP
ESP
Mech
Cy
ESP
E?P
Mech
Cy
ESP
ESP
Mech
cy
ESP
ESP
fly
Before
control
_
<30
-
5^
118
_
-
500
-
-
-
500-1000
<500
-
-
-
73
73
25
<1-10
100
-
1*0-100
—
<6oo
_
20
.
5800
_
_
ash in flue gas
After Before
control control
181
<30
60
110
-
50-290
792
2000
395
1*60-1600
-
500-1000
<500
111*
11-59
_
62
1*1*0
88
< 1-10
50
29-76
30
570
<6oo
7-19
20
16320
6600
9200-15900
-
After
control
13
-
-
-
-
..
18
-
1.3
-
15.1* ±6.1
-
_
6.5
-
12+5
-
-
-
-
„
-
-
61
-
-
-
261*
-
-
1*80+260
6080 10000
Analytical
method c
OES-P
-
XRF/WC
XRF/WC
INAA
OES
OES-P
-
FAAS
AAS
PAA
SSMS
.
INAA
FAAS
INAA
XRF
XRF
GC-MES
SSMS
.
SSMS
SSMS
OES-P
-
SSMS
SSMS
OES-P
-
XRF
INAA
INAA
(continued)
49
-------
TABLE 17 (continued). CONCENTRATIONS OF TRACE ELEMENTS IN COAL FLY ASH AND FLUE GAS (5)
Element
Vanadium
Zinc
Cone in
coal
22.5
_
<200
_
_
37^
28.5
1100
_
55-110
7.3
7.3
h6
Source
A
IE
IE
IE
_
IE
IE
IE
_
IE
SW
SW
IE
Control
method
ESP/WS
ESP
Mech
ESP
Cy
ESP
ESP
Mech
ESP
ESP
Cy
ESP
WS
ESP
Concn in Concn suspended
fly ash in flue gas
Before
control
116
-
200
_
-
.
WtO
5900
_
-
-
360
71*0
After Before
control control
— —
281*2
300
970
150-^80
_
1180
900
162
_
8100-13000
370
600
5900
After Analytical
control
_
Ik
-
1.5
-
27+32
-
_
0.7
lf3±23
113^0-18200
-
_
method
OES
OES-P
-
FAAS
SSMS
INAA
INAA
..
AAS
INAA
SSMS
FAAS
FAAS
SSMS -ID
a. Control equipment:
Mech = Mechanical collector
Cy = Cyclone collector
ESP = Electrostatic precipitator
WS = Wet scrubber
Ta, Sample was collected upstream from the mechanical collector.
c. Abbreviations for analytical methods.
OES = Optical Emission Spectroscopy-Betection Method
Unspecified
OES-P = Optical Emission Spectroscopy with Photographic
Detection
FAAS = Flameless Atomic Absorption Spectroscopy
SSMS = Spark Source Mass Spectroscopy
INAA = Instrumental Neutron Activation Analysis
AAS = Atomic Absorption Spectroscopy
SSMS-ID = Spark Source Mass Spectroscopy with Isotope Dilution
50
-------
Therefore, several studies have been made in recent years to determine the
fate of potentially hazardous elements in the coal and ash. The studies
which have been made to date concern the following locations.
1. A power plant in Illinois3
2. A midwestern power plant4
3. Chalk Point Station of the Potomac Electric Power Company5*31
4. Valmont Station of the Public Service Company of Colorado6*32
5. Allen Steam Plant of the Tennessee Valley Authority2
6. A Canadian steam-electric generating plant33
7. Three Northern Great Plains plants7"10
8. Widows Creek Steam Plant of the Tennessee Valley Authority29
The most significant result from these studies is that their conclusions
concerning the potential pollutants were consistent, even though the studies
were made on different sizes and types of systems with respect to megawatt
output, furnace type, and collector configuration. These studies all indi-
cate that certain potentially hazardous elements in coal (for example,
arsenic, beryllium, cadmium, lead, and selenium)5 are concentrated in or on
the small flyash particles, while certain others, such as mercury, are
emitted primarily as vapors. The following are brief summaries of these
studies.
Illinois Power Plant3
This study focused on a 105-megawatt (MW) plant using 60 tons of coal per
hour. While the method of firing was unspecified, the flyash collection
device was an electrostatic precipitator (ESP) with a rated efficiency of
97.7 percent. The separation of the particles into size classes was
accomplished by means of an in-stack cascade impactor which utilized
aluminum discs as collection surfaces. Inlet and outlet samples from the
ESP were analyzed by neutron activation for Fe, V, Cr, Ni, Mn, Pb, Sb, Cd,
Zn, and Se.
It was reported that, of the elements emitted from the electrostatic precipi-
tator, those concentrated in particulates in the submicron diameter range
were antimony, chromium, lead, selenium, and zinc. Nickel was more greatly
enriched in particulates in the 5-10 micron diameter range. The method of
analysis for all of the elements, except selenium, was graphite furnace
atomic absorption spectrophotometry. Selenium was determined by neutron
activation analysis. Potential sources of error were felt to be related to
problems with the sampling methodology, such as particle reentrainment,
calibration inaccuracies, and wall loss effects. Wall losses were believed
to be the most serious error, since they can range from 30-50 percent of
the total amount collected.
Midwestern Power Plant4
Neither size (output) of the unit nor the type of furnace was specified in
this report. The system utilized a cyclone collector for the flyash, and
51
-------
the coal burned was from southern Indiana. The purpose of this study was
to characterize the ash collected in the collector and the ash that passed
the collector. The ash from the collector hoppers was size-differentiated
physically in the laboratory by sieving and by aerodynamic separation.
The flyash passing the collector was sampled in situ using an Andersen
stack sampler. However, since the researcher failed to use a backup filter
in this sampler, the particles less than 0.5 micron in diameter were not
collected.
The following conclusions were derived from this study.
r, 1. The concentration of trace elements in the ash is dependent on
particle size. Generally, increasing concentrations are corre-
lated with decreasing particle size (see Tables 18, 19, and 20).
2. There is a definite enrichment of certain elements in the smallest
particles emitted from a power plant. These elements include lead,
thallium, antimony, cadmium, selenium, arsenic, nickel, chromium,
zinc, and sulfur.
The highest concentrations of the trace constituents occur in
;: particulates in the 0.5 - 10.0 micron diameter range, the size of
j particulate that can be inhaled and deposited in the pulmonary
I region of the respiratory system.
j 4. Presently available emission control devices for fine particulates
' are less effective for removing particulates in the size range
that contains the most toxic elements.
The theory advanced for this concentration of potentially toxic constituents
in fine particles involved the volatilization of elements in the high-
temperature zone of the boiler and preferential condensation of these
elements or their compounds onto the surface of fine flyash particles in
the cooler zones of the system. The methods used to perform the chemical
analysis in this study were direct current arc emission spectroscopy,
atomic absorption spectrometry, X-ray fluorescence spectrometry, and spark
source mass spectrometry.
Chalk Point Station5.31
This study involved sampling at two 355-MW units, each of which burned 116
tons per hour of pulverized coal. The samples collected were coal, bottom
ash, flyash from the economizer, flyash from the electrostatic precipitator,
flyash suspended in stack gas, and particles collected from surrounding
atmosphere. A cascade impactor with seven stages and a backup filter was
used to collect the flyash in the stack. The analysis for the 35 elements
under consideration was conducted by instrumental photon and neutron
activation methods.
Values were determined for several types of enrichment factors, including
the following1:
1. The enrichment of an element in the coal relative to its abundance
in the earth's crust.
52
-------
TftBLE 18. ELEMEN1B SHOWING PRONOUNCED CONCENTRATION TRENDS WITH
DECREASING PARTICLE SIZE (ppm unless otherwise noted) (If)
Particle diam,u
ko
30-UO
20-30
15-20
10-15
5-10
5
Cr
Zn
Analytical method
B. Airborne Fly Ash
11.3
7.3-11.3
k.7-7.3
3.3-^.7
2.1-3-3
1.1-2.1
0.65-1.1
1100
1200
1500
1550
1500
l60Q
29
62
67
65
76
17
27
Oji
oji
37
53
13
15
18
22
26
35
13
11
16
16
19
59
680
800
1000
900
1200
1700
1^60
hOO
kko
5^0
900
1600
7^0
290
1460
1+70
1500
3300
8100
9000
6600
3800
15000
13000
A. Fly
Ash Retained in Plant
Sieved fractions
Ito
160
7
9
1.5
7
10
10
12
20
180
500
Aerodynamically sized
90
300
1*30
520
^30
820
980
5
5
9
T /•»
15
20
^5
8
9
8
19
12
25
31
10
10
10
10
10
10
10
15
15
15
30
30
50
50
120
160
200
300
koo
800
370
100
iko
fractions
300
130
160
200
210
230
260
100
90
70
1^0
150
170
170
160
130
500
h 11
730
570
U80
720
770
1100
1^00
'i!s
0.01
0.01
• . •
• • •
U.U
7.8
Mass Frac
66.30
22.89
2.50
3-5^
3-25
0.80
0.31
0.33
0.08
8.3
25.0
is! 8
Analytical method
daadddd d a
(ape arc emission spectrometry. (b Atomic absorption spectrometry.
(c)X-ray fluorescence spectrometry. (d )Spark: source mass spectrometry.
53
-------
TABLE 19. ELEMENTS SHOWING LIMITED CONCENTRATION TRENDS WI3H
DECREASING PARTICLE SIZE (ppm unless otherwise noted) (4)
Particle diameter, y Fe,wt %
Mn
V Si,wt %
A. Fly Ash Retained in
74
44-74
• • *
18
700
600
Sieved fractions
150
260 18
Mg,wt %
Plant
...
0.39
C,wt %
• • •
11
Be
12
12
Al,wt %
• * •
9.4
Aerodynamically sized fractions
40
30-40
20-30
15-20
10-15
5-10
5
11.3
7.3-11.3
4.7-7-3
3.3-4.7
2.06-3.3
1.06-2.06
0.65-1.06
50
18
• • .
* • •
6.6
8.6
» * *
a
13
• • 0
12
* • •
17
• « •
15
150
630
270
210
160
210
180
b
150
210
230
200
240
470
* • *
250 3.0
190 14
340
320
320 19
330 26
320
Analytical method
a d
B. Airborne Fly Ash
150 34
240
420 27
230
310 35
480
23
0.02
0.31
. . •
0.16
0.39
...
d
0.89
• • •
0.95
• • •
1.4
0.19
0.12
0.21
0.63
2.5
6.6
5.5
d
0.66
0.70
0.62
0.57
0.81
0.61
• • •
7.5
18
21
22
22
24
24
34
32
55
43
60
• • *
1-3
6.9
• * •
« • •
9-8
13
d
19-7
16 ! 2
21.0
9^8
Analytical method
c d d
(a)Dc arc emission spectrometry.(b)X-ray fluorescence spectrometry.
(c)Atomic absorption. (d) Spark source mass spectrometry. e Oxygen fusion.
54
-------
TABLE 20 . ELEMENTS SHOWING NO CONCENTRATION TRENDS
(ppm unless otherwise noted)
Particle
Diameter
ym
>74
44-74
Bi
>2
>2
Sn
Cu
Co
A. Fly Ash Retained in Plant
Sieved Fractions
>2
>2
120
260
27
Aerodynamically Sized
>40
30-40
20-30
15-20
10-15
5-10
>5
>2
>2
>2
>2
>2
>2
>2
>2
>2
>2
>2
>2
>2
>2
220
120
160
220
220
390
490
75
76
55
50
55
46
54
B. Airborne Material
Ti
0.61
1.09
Ca
5.4
K
1.2
0.01
0.64
• • *
0.66
2.5
6.3
* • *
4.5
4.0
2.54
6.26
4.46
4.04
>11.3
7.3-11.3
4.7-7.3
3.3-4.7
2.06-3.3
1.06-2.06
0.65-1.06
>1.7
>3.5
>4.0
>4.8
>4.5
>4.4
...
7
11
18
19
16
18
* • •
270
390
380
...
330
300
...
60
85
90
95
90
130
...
1.12
• • *
0.92
...
1.59
...
1.08
4.9
• • •
4.2
• • •
5.0
...
2.6
4.9
4.2
9 m
5.0
• *
2.6
-------
2. The enrichment of the elements in the collected flyash relative
to the concentrations of these elements in the coal.
3. The enrichment factors for coal as a function of particle size
distribution.
4. The enrichment of an element in the suspended flyash relative to
its concentration in the coal.
The values for this last type of enrichment factor are shown in Figure 6.
The conclusions from this study agreed with those of the previous study with
respect to partitioning of the elements. Another conclusion regarded the
enrichment of elements in urban aerosols. "Enrichment factors for coal com-
bustion were compared with calculated enrichment factors for urban aerosols
collected in Boston, Northwest Indiana, and San Francisco. The enrichment
found in coal combustion products was not high enough to account for the
high enrichment factors of elements such as antimony, arsenic, selenium, and
zinc in urban aerosols."5
Valmont Power Station6'32
This study was made on a 180-MW unit employing a corner firing method. The
particulate emission control system consisted of a mechanical collector
followed by an electrostatic precipitator in parallel with a wet scrubber.
The samples collected were for all input streams and all outfall streams.
(See Figure 7 for sample points and flow rates.) Analytical methods used
to determine concentrations were wet chemistry, atomic absorption spectro-
photometry, and X-ray fluorescence spectrometry. Results of the chemical
analysis of the various streams are given in Table 21.
The enrichment ratios for the trace elements in each sample were calculated
relative .to the concentration of aluminum in the sample. Aluminum was used
as the basis for comparison because it is essentially nonvolatile at the
temperatures in the furnace. The results showed that the concentrations of
aluminum, iron, rubidium, strontium, yttrium, and niobium were approximately
constant in all of the outlet ashes. On the other hand, concentrations of
copper, zinc, arsenic, lead, and antimony were lowest in the bottom ash. The
concentrations of each of these elements increased progressively in the fly-
ash samples collected going downstream toward the stack. Based on the
volatilization-condensation postulation explaining the increasing down-
stream concentration of these elements, a mathematical model was developed
in which enrichment ratio was a function of the mass fraction of an element
volatilized in the furnace, the specific surface area of each ash stream,
and the total mass flow ratio of each ash stream.
The mass balance or imbalance closures for 16 elements are given in Table 22.
KaaKinen et al. believed that the imbalances may have been due to one or
more of the following factors.
1. Unsteady state conditions.
2. Sources and/or sinks of elements within the boundary of the mass
balance.
-------
Ill \if
— IODINE
! ANTIMONY
! SELENIUM
! ARSENIC
— T i
• LEAD
ZINC!
NICKEL!
COBALT!
<
MANGANESE!
CHROMIUM!
T
BARIUM!
STRONTIUM!
— ' i
4
MAGNESIUM!
RUBIDIUM!
SODIUM!
«— . |
I 1 1
BROMINE!
—
—
(IRON
• VANADIUM
_
CALCIUM
! POTASSIUM
!TANTALUM
ARHENIUM
! THORIUM
SCANDIUM!
! TANTALUM
— ALUMINUM," .
LL_J 1 LUL L_
20
10 8
1.0 0.8 0.5
-I »• ELEMENTS DEPLETED
Figure
in
ELEMENTS ENRICHED* 1
Note: Vertical location has no significance.
6. Enrichment factors of various elements on suspended particles
the stack with respect to the concentrations in the coal. (3U
57
-------
00
LEGEND
S SAMPLING LOCATION
BOUNDARY O.F MASS BALANCE
TOTAL MASS FLOW RATES IN KG/M1N AS SOLID OR'LIQUID
MECHANICAL
DUST
COLLECTOR
L
ELECTROSTATIC
PRECIPITATOR
" I
[FLY ASH|
1
1 ' 1
1 FFLY ASH!
IOOTTOM ASH
dp
SLAG
TANK
<$
MECHANICAL
COLLECTOR
HOPPER
S
V
w
c;
1
_/
ELECTRO
PRECIPI
HOPP
S
'
^
_r~\_-l
^^ *" SCRU
STATIC
TATOR S
PR ISLUR ro
J^
(<]J30)
1
ASH POND
ATMOSPHERE
j
~1
sV->
— (3.0)*
i
i
i
LSl/rr>
t
STACK
i
*
k
VALMONT
LAKE
Figure 7. Sample points and flow rates for Valmont, unit no. 5. (6)
-------
Ui
vo
TABLE 21. TRACE ELEMENTS IN PLANT SAMPLES FROM
VALMONT POWER STATION UNIT NO. 5 (6)
Concentration (ppm unless otherwise noted)
Element
Aluminuma
Irona
Copper
Zinc
Arsenic
Rubidium
Strontium
Yttrium
Niobium
Zirconium
Molybdenum
Antimony
Lead
Selenium
Mercury
Coal
0.1*9
0.37
9-6
7.3
-
2.9
120
3-0
0.76
13
0.99
-
-
1-9
0.070
Bottom
ash
8.8
6.6
82
58
15
hQ
1800
kk
12
220
3.5
2.8
<5
7.7
O.lUo
Mechanical
collector
hopper ash.
9.6
7.0
150
100
1*1*
50
21*00
61
16
260
12
h.7
13
l*.l
0.026
Precipitator
hopper ash
10.2
6.9
230
250
120
73
2500
68
19
210
hi
11*
66
27
0.310
Scrubber
inlet
fly ash
9.0
7.1*
280
360
130
51
2200
52
17
160
51*
11*
110
73
-
Precipitator
outlet
fly ash
9.2
7.h
320
370
150
56
2500
60
19
190
60
18
130
62
-
Scrubber
outlet
fly ash
7.h
h.9
290
600
280
28
2500
31
18
80
110
22
31*0
1*1*0
-
Scrubber
slurry
0.10
0.063
2.1*
2.2
1.1
0.50
21
0.1*9
0.1*9
1.8
0.53
0.10
0.91
0.33
o.oii*
Analytical
method
AAS
AAS
XRF
XRF
XRF
XRF
XRF
XRF
XRF
XRF
XRF/WC
XRF
XRF
XRF
FAAS
Concentrations in wt.
-------
TABLE 22. CLOSURE OF MASS BALANCE (6)
Element
Mo
Mo
Fe
Fe
Rb
Sr
Y
Zr
Nb
210Pb
210PO
Cu
Zn
As
Se
Sn
Pb
225Ra
Analytical
Method
Color.
XF
AA
XF
XF
XF
XF
XF
XF
Rad.
Rad.
XF
XF
XF
XF
XF
XF
Rad.
Relative
Based on analyses
of ashed coal
+10
- 4
- 7
-13
-25
-17
- 7
-20
-16
+23
+21
+11
+ 9
1*
-220a
+45a
+13a
-60a
Imbalance (%)
Based on analyses
of whole coal
-18
-35a
-~17
-15
-38
-13a
+70a
+55a
+46a
+62
+88a
a
Values involving analyses for which inaccuracies
or imprecisions are indicated to be a problem.
60
-------
3. Analytical errors in concentration values.
4. Errors in total mass flow rate estimates.
The researchers felt that in this case factors (1) and (2) were probably
insignificant while factors (3) and (4) could explain the observed
imbalances.32
Allen Steam Plant2* 28»31*»35
A study was made at the Tennessee Valley Authority's Allen Steam Plant which
included the sampling of all input streams, outfall streams, and environment
(air, soils, and water) accumulators. The in-plant testing was conducted
on a 290-MW cyclone unit burning 110 tons per hour of coal from Kentucky and
Southern Illinois. Figure 8 shows the in-plant sample points and Figure 9
diagrams the sample points in the environment. Soil composition was sampled
at 1-mile intervals from 20 miles south of the plant to 20 miles north of
the plant. The sampling layout was based on atmospheric dispersion modeling
calculations using average meteorological conditions for the area and data
on particulate emission characteristics. The north-south transect was
chosen because of the predominance of north-south winds in the area of the
plant. Mud samples were obtained on the bank of the Mississippi River four
and fifteen miles north of the plant. These samples would include an effect
from discharges to the river upstream of the plant area.
Determinations were made for concentrations of 33 elements for the inplant
samples and for 28 elements in the environmental samples. Analytical tech-
niques used for these determinations were neutron activation, isotope-
dilution spark-source mass spectrometry, gas chromatography with microwave
emission detection, and flameless atomic absorption. Table 23 presents
the results of the in-plant chemical analysis of the samples, the mass flow
calculations, and the mass balances. The results of the soil sample
analysis for the major elements are given in Table 24 and those for the
trace elements in Table 25. Table 26 contains the trace element analysis
for the water and sediment samples. Results for the determination of
mercury content of mosses up to 20 miles north and south of the power plant
are given in Table 27.
Table 28 is a comparison of soil analyses from the Allen Steam Plant with
the world averages for similar soils. The elements which are concentrated
in the plant's flyash over the values for Memphis area soils or similar soils
around the world are Se, B, Cu, Ni, Cd, Pb, As, V, Zn, Ga, Ge and Li. If
the high concentrations of trace elements in the soil near Allen were due to
flyash fallout, a sharp decrease in concentration with depth might be
expected. However, there was no appreciable concentration change with soil
depth for Cd, Zn, Pb, Cu, As, and V. For the remaining elements the back-
ground data for soils was limited.
The authors felt that, although the data were not conclusive, the environ-
mental samples did not indicate any major impact of the Allen Steam Plant
emissions on concentrations of trace elements in the surrounding environment.
61
-------
ro
1. COAL SAMPLE
2. SLAG SAMPLE
3. INLET AIR
4 BEFORE ELECTROSTATIC PRECIPITATOR
5 AFTER ELECTROSTATIC PRECIPITATOR
6. STACK SAMPLE AT 268 ft ABOVE GROUND LEVEL
7. ALTERNATE SAMPLE LOCATION FOR NUMBER 4
Figure 8. Sample points for Allen Steam Plant, unit no. 2 (28)
-------
North
-• 20 miles
5-mile radius
•• 20 miles
South
• Fallout Buckets
A Environmental Air Samples
Soil samples taken at I mile intervals
on north-south transect except on
mile 4 north.
Mud samples taken on bank of
Mississippi River 4.10 and 15 miles
north of Allen Steam Plant.
Figure 9. Schematic of sampling locations for soil cores, fallout, and
environmental air samples. (28)
63
-------
TABLE 23. TABULATION OF ELEMENTAL CONCENTRATIONS AND MASS BALANCE RESULTS FROM ALLEN STEAM PLANT (28)
Concentration (ppm unless otherwise indica
Element
A.K"
Agf
Al*
Alc
As*
Asc
Bc
"
Ba*
Ba''
Be'
Bic
Br6
Run
5
7
9
7
5
7
9
5
7
9
5
7
9
5
7
9
5
7
9
5
9
5
7
9
5
7
9
7
5
9
Coal
<2
<2-5
<10
1.05%
1.3%
1 .06%
0.9%
>1%
1%
4.7
18
3.8
5
5
200
100
200
91
79
100
150
100
<5
0.3
<5
<10
2.6
2.0
S.T.
<2
<20
7.6%
9.7%
6.6%
5%
>10%
5%
<10
0.5
1
2
300
200
300
600
300
500
300
5
0.5
<10
<10
<1
<0.5
P.I.
<3-5
<1
<2
10
5.7%
7.4%
6.9%
5%
>10%
15%
27
349
46
5
1000
40
3000
250
2000
400
3000
300
1700
15
3
17
2
<2-5
<5
P.O.
~1
3
20%
3.5%
20%
>10%
10%
138
50
100
30
20
300
150
300
300
150
100
5
1
<10
2
10
tprl)
Stack Coal
<3
1
<6
20 <13
1.31 X 104
38% 1.6 X 104
1.3 X 104
1.1 X 104
>10% >1.3 X 104
1.3 X 104
5.9
93 23
4.7
6.2
100
6.2
250
170 130
250
114
99
130
100 190
130
<6.3
0.3 0.4
<6.3
5 <13
3.3
2.5
Mass flow (g/min)
S.T.
<0.20
<1.0
7.5 X 103
9.9 X 103
7.2 X 103
5.0 X 103
1.0 X 104
5.5 x 103
<0.99
0.05
0.10
0.22
30
20
33
66
30
51
33
0.50
0.05
<1.1
<1.0
<0.1
<0.05
P.I.
<0.20- 0.33
<0.07 '
<0.10
0.68
3.8 X I03
5.0 X 103
3.4 x 103
3.3 X 103
>6.8 x 103
7.3 X 103
1.8
24
2.2
0.33
68
2.0
200
17
97
27
200
20
83
1.0
0.21
0.83
0.14
<0.13-0.33
<0.24
Imbalance
-14
-6.9
-18
-25
-1.S
-52
-93
-64
-8
-71
-48
77
-63
-11
-35
P.O. Stack
-0.002 0.001
0.0056 0.024
3.7 X 102 4.5 x 102
68
3.8 X 102
>1.9 X 102 >1.2X 102
1.9 X 102
0.26 0.11
0.097
0.19
0.056 0.12
0.039
0.57
0.28 0.20
0.59
0.57
0.28 0.12
0.19
0.01
0.0019 0.00036
<0.019
0.0037 0.0059
0.019
(continued)
-------
TABLE 23. (continued)
TABULATION OF ELEMENTAL CONCENTRA.TJ.UJNa AND MASS BALANCE RESULTS FROM
ALLEN STEAM PLANT (28)
Concentration (ppm
Element
Ca*
Cac
Cec
Cdc
Cl^
Co*
01
Ul
Coe
Cr6
CfC
Cs»
Cuc
Dyc
Eu"
Run
5
7
9
5
7
9
9
5
7
9
5
9
5
7
9
5
7
9
5
7
9
5
7
9
5
9
5
7
9
9
5
9
Coal
0.36%
0.51%
0.38%
1%
1%
0.5%
-30
0.44d
0.50d
407
355
3.5
5
3.3
10
<10
7
23
21
65
150
30
1.5
1.5
50
100
50
<10
0.31
0.17
S.T.
2.06%
4.4%
-2.7%
5%
5%
3%
2
2
15
28
19
<50
40
895
111
180
300
500
<200
8.8
8
300
200
200
0.7
1.4
unless otherwise indicat
P.I.
1.57%
2.2%
1.4%
3.5%
3%
<2
<2
<10-20
50
<5-50
35
51
25
50
70
200
356
250
170
70
15
21
300
400
400
1.6
1.8
P.O.
1.2%
0.49%
0.3%
> 1%
1%
<0.7
7
1000
26
58
30
40
300
200
200
40
4
200
400
400
(1H\
.t-U )
Stack Coal
0.45 X 104
<1.0% 0.64 X 104
0.47 X 104
1.3 X 104
>1% 1.3 X 104
0.6 X 104
-37
0.55
<0.7
0.63
510
460
4.4
11 6.3
4.1
13
10 <13
9
29
26
81
150 190
37
1.9
1.9
63
1000 130
63
<13
0.40
0.21
Mass flow (g/min)
S.T.
2.0 X 103
4.5 X 103
3.0 X 103
5.0 X 103
5.1 X 103
3.3 X 103
0.20
0.22
1.5
2.9
2.1
<5.1
4.4
89
11
20
30
51
<22
0.87
0.88
30
20
22
0.07
0.15
P.I.
1.04 X 103
1.5 X 103
6.8 X 102
2.3 X 103
>6.8 X 102
1.5 X 103
<0.13
<0.14
<0.49-0.97
3.3
<0.24-2.4
2.3
3.5
1.2
3.4
3.4
14
17
17
12
3.4
1.0
1.02
20
27
19
0.11
0.09
Imbalance
-32
-6.3
-22
-44
-20
-14
1.6
-19
-13
42
-42
-67
-1.6
0
-21
-64
-35
-55
14
P.O.
22
9.5
5.7
19
<0.0013
0.014
1.9
0.048
0.11
0.56
0.078
0.59
0.38
0.37
0.078
0.0078
0.38
0.74
0.78
Stack
<»
>„
-------
TABLE 23. (continued)
TABULATION OF ELEffiNTAL CONCENTRATIONS AND MASS BALANCE RESULTS FROM
ALLEN STEAM PLANT (28)
Concentration (ppm unless otherwise indica
Element
Eu<-
Fe"
Fec
Ga*
Gac
Gec
Hf6
Hg'
Hge
•
K"
Kc
La6
Lac
Lic
Run
9
5
7
9
5
7
9
7
5
9
5
9
5
9
5
9
5
7
9
5
7
9
5
7
9
5
7
9
9
5
7
9
Coal
~1
1 .46%
2.0%
1.3%
2%
-2%
2%
13
15
5
4.4
3.0
0.064
0.170
0.063
0.20%
0.25%
0.22%
0.17%
0.1%
0.06%
4.8
6
5.0
-10
30
100
25
ST.
10.3%
13.2%
10.1%
10%
-8%
10%
40
<10
2
<10
0.07
0.09
1.14%
1 .46%
0.95%
1.5%
3%
0.5%
35
46
42
300
500
200
P.I.
9.5%
13.9%
9.3%
10%
>2%
10%
71
100
70
200
70
0.11"
0.13d
0.04
0.10
0.043
1.17%
1 .97%
1.65%
1.7%
1%
0.7%
30
36
32
350
200
300
P.O.
9.6%
23.5%
10%
>2%
10%
93
100
40
200
40
<1
-10
0.88%
1.28%
0.3%
0.5%
0.2%
19
70
100
200
ted)
Stack Coal
-1.3
1.83X 104
4.0% 2.5 X 104
1.6 x 104
2.5 x 104
>2% -2.5 x 104
2.5 X 104
130
16
19
6.3
5.5
3.7
0.080
0.212
0.079
0.25 X 104
0.29% 0.31 X 10"
0.27 X 104
0.21 X 104
0.05% 0.13 x 104
0.07 x 104
6.0
12 7.5
6.3
-13
37
50 130
31
ST.
1.0 X 104
1.4 x 104
1.1 x 104
9.9 X 103
-8.2 x 103
1.0 X 104
4.0
<1.1
0.20
<1.1
0.0069
0.0099
1.1 X 103
1.5 X 103
1.0 X 103
1.5 X 103
3.1 X 103
5.5 X 102
3.5
4.7
4.6
30
51
22
Mass flow
P.I.
6.3 x 103
9.5X 103
4.5 X 103
6.6 X 103
>1.4 X 103
4.9 X 103
4.8
6.6
3.4
13
3.4
0.007d
0.006d
0.0027
0.007
0.0021
7.8 X 102
1.3 X 103
8.0 X 102
1.1 x 103
6.8 X 102
3.4 X 102
2.0
2.46
1.5
23
14
15
(g/min)
Imbalance
-11
-6.0
-3.1
-34
-40
-31
-88
-85
-25
-9.7
-33
24
190
27
-8.3
-4.5
-3.2
43
-50
19
P.O. Stack
1.8 X 102 4.8 X 101
4.6 X 102
1.9 X 102
>3.7 x 10' >2.4 X 1
1.9 X 102
0.17 0.15
0.19
0.078
0.38
0.078
<0.0019
-0.019
16 3.5
25
5.7
9.3 0.6
3.9
0.035 0.014
0.13
0.19 0.059
0.39
(continued)
-------
TABLE 23. (continued)
TABULATION OF ELEMENTAL CONCENTRATIONS AND MASS BALANCE RESULTS FROM
ALLEN STEAM PLANT (28)
Concentration (ppm
iilement
Mg*
Mgc'
Mnb
Mnc
Mo
Mo
Na6
Nac
Mb''
Ndc
Nic
fc
Run
5
7
9
5
7
9
5
7
9
5
7
9
5
9
5
7
9
5
7
9
5
7
9
5
7
9
9
5
7
9
5
7
9
Coal
0.15%
0. 1 7%.
0.17%.
0.15%
0.1%
0.15%
53
51
54
100
200
100
47
20
20
10
20
0.063-0.63%
0.072%
0.069%
0.05%
0.15%
0.03%
<15
<10
-5
-30
<100
150
«100
50
S.T.
0.98%
1.3%
0.41%
0.6%
0.5%
0.7%
416
382
418
1000
700
1000
100
70
80
0.33%
0.29%
0.32%
0.3%
0.3%
0.2%
2
<10
2
500
150
500
60
20
unless otherwise indicated)
P.I.
0.89%
1.16%
0.55%
1%
>1%
0.7%
325
316
323
1000
1000
700
150
700
200
0.59%
0.58%
0.7%
0.5%
>1%
0.3%
6
10
15
500
1000
500
200
300
500
P.O. Stack
2.5%
0.88%
0.8%
0.7'% 1%
0.4%.
335 218
550
1000
500 900
500
200
150 70
20
0.40% 0.33%
0.28%
0.15%
0.3% 0.09%
0.2%
20
10 20
10
1000
500 300
1000
200
300 200
200
Coal
0.18 X 104
0.21 X 104
0.21 X 104
0.18 X 104
0.12 X 104
0.18 x 104
66
64
67
130
250
130
59
25
25
12
25
790-7900
900
860
630
0.19 X 109
370
<19
< 13
-6.3
-37
<130
190
<130
63
S.T.
9.7 X 102
1.3 X 103
4.5 X 102
5.9 X 102
5.1 X 102
7.7 X 102
41
39
46
99
72
110
9.9
7.2
8.8
3.3 X 103
3.0 X 102
3.5 X 102
3.0 X 102
3.1 X 102
2.2 x 102
0.20
6.8 X 102
3.4 x 102
22
21
16
66
68
34
10
48
9.7
3.9 X 102
4.0 X 102
3.4 X 102
3.3 X 102
>6.8 X 102
1.5 X 102
0.40
0.68
0.73
33
68
24
13
20
24
(g/min)
Imbalance
-13
-0.4
66
-31
-38
-4.5
-6.3
-7.5
27
-44
11
-20
360
-26
-22
-20
0
-48
0.0
-56
-58
P.O.
17
15
13
7.8
0.62
1.1
1.9
0.93
0.97
0.38
0.28
0.039
7.4
5.5
2.85
5.6
3.9
0.038
0.019
0.019
1.9
0.93
1.9
0.38
0.56
0.39
Stack
30
12
0.26
1.1
0.083
3.9
I.I
0.024
0.36
0.24
(continued)
-------
TABLE 23. (continued)
TABULATION OF ELEMENTAL CONCENTRATIONS AND MASS BALANCE RESULTS FROM
ALLEN STEAM PLANT (28)
00
Concentration (ppm unless otherwise indicated)
Element
Pbc
Prc
Rb6
Rbc
Sh
Sbb
Sbc
Sc"
Se"
Sec
Sf
Sm*
Smc
Snc
Src
Run
5
7
9
9
5
7
9
5
7
9
5
9
5
5
7
5
7
9
5
7
9
9
5
7
9
5
9
9
7
7
9
Coal
<5
-30
<20
-10
17
20
19.4
40
200
17
3.5%
5.1%
<1
3.4
3.6
3.2
3.2
2.6
3.2
6
5%
5%
5%
1
1
-10
20
200
S.T.
3
10%
30%
0.12
200
500
60
P.I.
80
300
250
162
<120
650
300
200
3.2
7
<\0
25
29
25
24(<60)
23
<32-48
20
30%
>5%
30%
20
300
200
P.O. Stack
800
100 70
100
100
50 30
10
10.5%
10
<10 <10
10 5
10
290 44
760
200
30%
>5% >5%
10%
20 20
100 100
60
Mass flow (g./min)
Coal
<6.3
-37
<25
-13
21
25
24.3
50
250
21
4.4 X 10"
6.4 X 104
<0.75
4.3
4.5
4.0
4.0
3.3
4.0
7.5
6.3X 104
6.3X 104
6.3 X 104
1.3
1.3
-13
25
250
S.T.
0.30
<1.0
0.33
2.8
11
40
4.4
<0.02
0.79
2.0
2.3
2.4
1.0
1.5
2.2
3.0 X 104
>1.0 X 104
3.3 X 104
0.01
20
51
6.6
P.I.
5.3
20
12
11
<5.8
43
20
9.7
0.2
0.47
<0.68
1.7
2.0
1.2
1.6«4.0)
1.6
<1.5-2.3
0.97
2.0 X 104
>3.4 X 103
1.5 X 104
1.4
20
9.7
Imbalance
1.5
0.19
0.19
-34
66 0.19
0.093
-33 0.019
2.0 X 102
0.019
<0.019
-14
-4.4 0.019
-10 0.019
0.54
1.4
-58 0.39
-21 5.7 X 102
>93
-24 1.9 X 102
-14 0.037
-72 0.19
0.12
Stack
0.083
0.036
<0.012
0.0059
0.052
>59
0.024
0.12
(continued)
-------
TABLE 23. (continued)
TABULATION OP ELEMENTAL CONCENTRATIONS AND MASS BALANCE RESULTS FROM
ALLEN STEAM PLANT (28)
vo
Concentration (ppm unless otherwise indica
Element
Ta"
Ta^
Tbc
Tec'
Th"
Thf'
Ti"
Tic
Tf
U"
if
V6
vc'
Wb
w
Run
5
9
7
9
5
9
5
9
7
5
7
9
5
7
9
9
7
5
7
9
7
5
7
9
5
7
9
9
7
9
Coal
O.I, <1
<1
<10
-1
3
1
2.4
3
580
500
710
650
700
700
<2
3
3.3
1.67
21
69
21
12
50
30
<5
<10
1
S.T.
2
200
3
3
20
3300
2400
3000
3000
3000
2000
-i
1
17
14
135
560
125
30
100
100
1
P.I.
1.2
1.3, <5
50
<1
-10
23
18
10
4200
3500
3700
-3000
1500
5000
40
100
15
21
17
100
211
780
200
100
200
350
50
5
P.O.
20
-------
TABLE 23. (continued)
TABULATION OF ELEMENTAL CONCENTRATIONS AND MASS BALANCE RESULTS FROM
ALLEN STEAM PLANT (28)
Element Run
Zn'' 5
7
9
Zrc 5
7
9
a
Coal
250
<200
85
40
<30
S.T. + P.I. - coal
coal
S.T.
900
«200
100
10
100
10
i on
P.I.
3000
500
3000
10
100
40
P.O. Stack Coal S.T.
9000 310 89
500 300 <250 <20
900 110 1!
100 1.0
50 50 20
10 <37 1.1
Mass flow (p/min)
P.I.
200
34
150
0.66
6.8
1.9
imbalance pQ ^
-6.8 17
0.93 0.36
46 1.7
0.19
--46 0.093
0.019
rSpark source masi spcctroscopy.
Isotope dilution SSMS
^Atomic absorption spcctroscopy.
ST - Slag tank solids
PI - Precipitator Inlet Flyash
PO - Precipitator Outlet Flyash
(continued)
-------
O&BLE 2k- MAJOR ELEMENT DATA (PPM, DRY WEIGHT) FOR SOIL SAMPLES
COLLECTED FROM A UO-MILE NORTH-SOUTH TRANSECT AT
THE ALLEN STEAM PLANT (MEMPHIS, TENNESSEE) (28)
Values represent means of two core samples collected 100 yd apart
Miles
North or
South
N-20
N-19
N-18
N-17
H-16
N-15
N-ll*
N-13
H-12
N-ll
N-10
N-9
N-8
N-7
H-6
N-5
N-1+
H-3
N-2
N-l
S-l
S-2
S-3
s-i*
S-5
Al Fe Mg
29,300
39,760 29,500 8060
39,350 35,200 8160
51,700
1*1*, 900
^3,300
1*1*, 750 39,900 8720
1*0,830 35,600 79^0
1*1,600
39,600
1*1*, 500
1*7,500
1*6,900
1*7,000
53,000
1*2,710 35,600 8820
29,600
37,iUo 36,000 80^0
UO,650 30,900 7930
kO,k3Q 26,700 7281
32,500
3^,690 38,500 8060
33,820 39,600 ^830
Ca Na Ti
2300 86^0 25^0
U700 6580 27^0
5000
5000
5000
3800 5390 3230
UlOO 6990 30^0
inoo
3^00
U300
5000
5000
UlOO
1*700
3800 6U35 3250
3000
kooo 6920 3150
1*300 7120 2830
2600 9970 2570
1*700
5000 6750 2710
2200 6730 3000
Mn
5U7
61*0
797
6U7
387
656
518
375
553
730
71
-------
TABLE 25. MINOR ELEMENT DATA FOR THE TOP 1 CM OF SOIL COLLECTED FROM A 40-MILE NORTH-SOUTH TRANSECT AT THE ALLEN STEAM PLANT
Values (ppm, dry weight) are means of two core samples collected 100 yd apart at each sampling site (28)
Miles
north or
south
N-20
N-19
N-18
N-17
N-16
N-15
N-14
N-13
N-12
N-ll
N-10
N-9
N-8
N-7
N-6
N-5
N-4
N-3
N-2
N-l
S-l
S-2
S-3
s-4
s-5
8-6
S-7
S-8
S-9
S-10
s-n
S-12
S-13
S-l4
S-15
s-16
S-l?
S-18
S-19
S-20
I-A
Rb Cs
118
16
132
162 41
158
134 20
146
128 17
138
152 2k
156
17k 6k
156
172
178
136
120
130
122
124 17
118
138
Hk
II -A IV-A
Ba Pb
650 10
10
700 18
20
100
75
640 15
635 19
21
38
23
5
5
11
9
17
16
590 49
715 50
781 30
20
595 18
494 28
V-A I-B
As Sb Cu
1.4 70
i.o 70
1.2 83
1.7 105
1.2 97
1.5 90
11.5 1.5 87
1.2 85
I.o 92
l.l 93
1.4 97
2.0 103
1.2 94
1.7 106
1.8 104
10.0 1.5 83
1.1 78
1.4 88
0.9 75
7.4 1.2 74
1.2 74
7.6 1.4 89
1.4 84
Au Zn
0.048
0.034
0.050 360
711
0.032 425
461
627
537
368
0.055 467
560
462
367
675
423
256
425
0.019 ^56
0.033 348
0.036 362
4l6
573
351
II-B
Cd
0.5
0.5
4.0
1.8
0.4
3.5
4.0
1.2
1.5
0.9
0.3
0.3
0.4
1.5
1.2
0.7
III-B
Hg
0.028
0.024
0.034
0.060
0.042
0.067
0.046
0.033
0.034
0.034
0.035
0.047
0.038
0.043
0.049
0.045
0.030
o.o44
o.o4o
0.025
0.033
0.043
0.029
0.020
0.035
0.018
0.035
0.036
0.022
0.025
0.022
0.026
Sc
11.0
11.5
14.8
20.2
18.0
18.0
17.0
14.0
17.2
17.6
20.5
20.3
19.3
22.0
20.7
14.9
11.1
14.7
13.6
11.5
13.6
16.3
14.5
La
41
41
48
52
49
48
50
44
49
51
54
51
47
55
56
48
45
48
41
45
^9
53
47
IV-B
Hf
14.2
12.0
12.5
8.0
9.3
7.4
13.8
13.0
11.0
9-1
7.5
14.0
7.1
7.3
6.7
14.5
12.3
14.5
12.3
14.0
10.0
11.5
14.5
V-B
V
6l
64
75
63
70
60
64
55
58
52
Ta
0.9
0.8
0.9
0.8
0.8
1.0
1.0
1.0
1.0
1.1
0.9
0.9
1.0
0.8
0.9
0.8
1.0
0.4
1.0
0.8
1.0
0.9
VIII-B
Co
12.6
14.5
19.0
17.1
15.7
18.0
14.3
15.4
15.3
16.0
17.0
17-5
15.3
23.6
16.0
1J-.7
15.1
12.8
10.5
13.7
14.1
13.5
La
series
Eu
1.4
0.9
1.0
1.1
1.1
1.1
1.0
1.0
1.0
1.1
1.0
1.0
0.9
1.1
1.0
1.5
1.0
0.9
1.0
1.0
1.1
1.2
Ac
series
Th
12
10
13
15
13
14
13
12
13
14
15
14
14
13
17
13
12
14
12
11
12
12
9
u
3
4
4
4
4
4
4
4
4
5
4
-------
OJ
TABLE 26 . MINOR ELEMENT CONCENTRATIONS IN SEDIMENTS AND WATER COLLECTED IN THE
IMMEDIATE VICINITY OF THE ALLEN STEAM PLANT IN MEMPHIS, TENNESSEE (28)
Source
Steam plant intake (McKeller Lake)
Above settling pond outfall (Horn Lake Cutoff)
Mouth of settling pond outfall (Horn Lake Cutoff)
Below settling pond outfall (Horn Lake Cutoff)
Above pumping station (Horn Lake Cutoff)
North Horn Lake
Cooling water effluent canal
Below cooling water effluent outfall
(Mississippi River)
a
Water
Cd
0.008
0.005
0.010
0.011
0.008
0.002
0.009
0.005
Cu
0.03
0.03
0.0k
o.o4
0.10
0.03
0.03
0.02
Fb
0.01
0.02
0.01
0.02
0.11
0.02
0.02
0.01
Zn
0.28
0.13
0.29
o.Uo
0.4?
0.26
0.17
0.20
Cd
0.10
1.UO
l.UO
0.40
0.60
0.20
O.lU
b
Sediments
Cu
3-1
12.0
13-0
12.0
13-0
17.0
4.3
Pb
2.5
11.0
11.0
10.0
14.0
14.0
3.3
Zn
22.0
51.0
55.0
64.0
59-0
67.0
20.0
All water values - ppm.
All sediment values - ppm, dry weight
-------
TABLE 27. MERCURY CONCENTRATIONS (PPM, DRY WEIGHT) IN MOSSES (DICRANUM)
EXPRESSED AS A FUNCTION OF DISTANCE
ALLEN STEAM PLANT IN MEMPHIS,
Miles
North or South
W-20
N-18
N-16
N-lU
N-12
N-10
N-8
N-6
N-U
N-2
0
S-2
S-k
s-6
s-8
S-10
S-12
S-lk
s-i6
s-i8
S-20
NORTH AND SOUTH OF THE
TENNESSEE (28)
Hg Concentration
(ppm, dry weight)
0.1k
0.^3
0.07
O.lU
0.25
0.17
0.12
0.32
0.06
O.k6
0.17
0.1k
0.08
0.11
0.06
0-35
74
-------
TABLE 28. COMPARISON OF ELEMENTAL CONCENTRATIONS
IN SOILS COLLECTED IN THE ALLEN STEAM PLANT
ENVIRONMENTAL STUDY WITH WORLD AVERAGES (28)
World averages compiled from Vinogradov, Bowen, Goldschmidt
and Wedepohl for mineralogically similar soils
\_n
Element
Rubidium
Cesium
Barium
Lead
Arsenic
Antimony
Copper
Gold
Zinc
Cadmium
Mercury
Scandium
Lanthanum
Hafnium
Vanadium
Tantalum
Cobalt
Europium
Thorium
Uranium
Soils in Allen
Range (ppm)
ll!4-178
16- 6U
1*914-781
5-100
7.^-11.5
0.9-2.0
70-106
0.019-0.055
256-711
0.3-^.0
0.018-0.067
11.0-22.0
Ui- 56
6.7-1^.5
52-75
0.8-1.1
10.5-23.6
0.9-1-5
9-17
3-5
Steam Plant Area
Average (ppm)'
ll*l
28
656
26
9.1
i.U
88
0.038
U58
l.U
0.036
15-5
U8
11.2
62
0.9
15. U
i.l
13
h
World
average (ppm)
100
10
500
12
5
~1
20
<0.1
50
0.5
0.07
7
50
8
100
22
8
1
~6
1
Ratio of Allen Steam Plant
Average to World Average
l.lt
2.8
1.3
2.2
1.8
1.1*
k.k
0.38
9.2
2.8
0.51
2.2
0.96
1.1*
0.62
0.01+
1.9
1.1
2.2
l+.O
-------
The results of the study on the in-plant samples were very similar to those
of other investigators in that the elements were divided into three classes
as follows.
1. Class I - Elements which showed approximately equal concentrations
in all phases of the ash sample. This class included Al, Ba, Ca,
Ce, Co, Eu, Fe, Hf, K, La, Mg, Mn, Rb, Sc, Si, Sn, Sr, Ta, Th, and
Ti.
2. Class II - Elements which showed enrichment in the flyash. This
class included As, Cd, Cu, Ga, Pb, Sb, Se, and Zn. These elements
were concentrated in the inlet flyash as compared to the bottom
ash and in the outlet flyash as compared with the inlet flyash.
3. Class III - Elements which remained essentially completely in the
vapor phase. This class included Hg, Cl, and Br.
The other elements analyzed in this study (Cr, Cs, Na, Ni, U, and V) could
not be assigned to a specific class based on this data alone. However, they
seemed to be intermediate between Class I and Class II.
Canadian Steam Plant33
This study consisted of the analysis of 27 monthly coal samples (which were
composites of weekly samples from all generating stations) and 5 sets of
coal, ash, and flue gas samples collected at one generating station. The
samples were analyzed by neutron activation for 33 elements and by existing
methods for others (Hg, Cd, Ag, Pb, B, F, and Be). The average concentra-
tions of the elements from the 27 coals and the averages of elements from
the coal from the single source were in good agreement.
The conclusions drawn from this study agreed with those previously reported.
Certain elements tended to concentrate in different ashes (see Table 4).
The authors felt that, of the elements analyzed in this study, only chlorine,
mercury, fluorine, and bromine were emitted from the stack in any signifi-
cant amount. More data is needed for gallium, arsenic, and selenium emis-
sions before any conclusions may be made on the emissions of these elements.
The mass balance results for these elements were significantly low on the
side of the combustion products.
Three Northern Great Plains Plants7"10
This report summarized the trace element emissions from three coal-fired
steam-electric generating plants. The unit sampled at Plant "A" was a bal-
anced draft, tangentially-fired, 330-MW boiler with three venturi scrubbers
for particulate emission control. This plant used Wyoming sub-bituminous
coal at a rate of 141 tons per hour. The unit sampled at Plant "B" was a
tangentially fired, 350-MW boiler with a hotside electrostatic precipitator
for particulate emission control. The plant also used Wyoming sub-bituminous
coal. The coal usage rate at this plant was 138 tons per hour. The unit
which was sampled at Plant "C" was a 250-MW cyclone boiler with a mechanical
cyclone used as the particulate emission control device.
76
-------
At each of the plants, all of the incoming and outgoing streams were sampled
periodically over a time interval of two days. The flue gas ducts were
sampled utilizing a wet electrostatic precipitator sampler. Collection
efficiency for this sampler was reported as 99 percent when compared to the
EPA filter method. A materials balance approach for 27 elements was used to
characterize the effluents around the power plants.
In discussing the results, we note that the amount of an element which exits
a steam-electric power plant in each of the various ash streams depends on
several factors, including the following.
1. Elemental concentration in the coal.
2. Boiler configuration and firing conditions.
3. Flue gas emission control devices.
4. Properties of the element and its compounds.
As previously mentioned, the first factor depends on the source and type of
coal. The latter three factors determine the fractional distribution of the
elements among the exiting ash streams.7
Ash distribution among exiting ash streams varied with the plants„ The
tangentially fired boilers at Plants A and B each produced about 22 percent
bottom ash, while Plant C's cyclone boiler produced about 63 percent bottom
ash. The venturi scrubbers at Plant A and the electrostatic precipitator at
Plant B showed collection efficiencies of 99.6 percent and 99.1 percent, res-
pectively. The mechanical collector at Plant C had approximately 65 percent
collection efficiency. Thus, Plants A, B, and C had total ash percents in
the flue gas of 0.3 percent, 0.7, and 12.9 percent respectively.
This study agreed with other studies discussed in its recognition that ele-
ments are partitioned into three distinct groups with respect to their dis-
tribution in the ash fractions. Enrichment was noted in the flue gas plus
flyash at all three plants for the following elements: S, Hg, Cl, Sb, F, Se,
V, Pb, Mo, Ni, B, Zn, Cd, Cr, Cu, Co, U, As, and Ag. Elements which were
approximately equally distributed in the bottom ash and flyash included Ba,
Be, Fe, Al, Ca, Ti, Mn, and Mg. Some elements enriched in the flue gas (S,
Hg, and Cl) were primarily discharged to the atmosphere in the vaporous
phase.
The volatilization-condensation theory of enrichment of certain elements in
the flyash or stack gas, previously observed by Davison, Natusch, and
Wallace, was again noted in this study. This theory holds that some ele-
ments or their compounds are volatilized in the fire box of the boiler.
Subsequently these vaporous phase elements recondense completely or partially
or are discharged through the stack in the gaseous phase. The latter
instance is true of sulfur, mercury, and chlorine.
Condensation of elements in the cooler gas streams results in higher concen-
tration of these elements in the fine particulate fractions of flyash, tor
two reasons.
77
-------
1. Condensation occurs either by nucleation or by deposition on
previously formed particles. Since residence times between vola-
tilization and condensation are relatively low, any nucleation
will produce relatively small particles.
2. Deposition occurs on the particle surface and is, therefore,
dependent on particle surface area. Since surface area is greater
for finer particles, small particulates display increased concen-
trations of elements which tend to recondense.
The results of the chemical analysis for each of the plants are given in
Tables 29, 30, and 31.
Widows Creek Power Plant29
This study involved a sampling program around a 125-MW, tangentially fired
boiler equipped with a mechanical flyash collector. The purpose of the pro-
ject was to quantify the potentially hazardous pollutants in the waste
streams of a typical, coal-fired utility boiler. In this study 22 trace
elements, nitrates, sulfates, polycyclic organic compounds, and polychlor-
inated biphenyls were identified as potentially hazardous air pollutants
resulting from the combustion of coal.
Major findings of this study were as follows:
1. The mass balance for approximately half the elements was closed
within acceptable limits of 20 to 25 percent. The causes of the
imbalance were inefficient collection of the vaporous metals in
the flue gases and analytical errors, particularly in the analysis
of coal.
2. An enrichment of the various trace constituents occurred to a
moderate degree in the cooler ash streams and to a higher degree
in the finer particles of the flyash.
The analytical results for the samples collected are given in Table 32.
With the exception of antimony, barium, beryllium, manganese, tellurium,
titanium, and vanadium, there was a tendency for potentially hazardous
pollutants to progressively concentrate in the ash streams farther down-
stream from the boiler. Fine particles were enriched with most of the trace
metals. Beryllium, cadmium, copper, and zinc exhibited the greatest degree
of enrichment in these particles. Another finding was that organic com-
pounds found in the coal, such as polycyclic organic material. (POM), were
approximately evenly distributed between the bottom ash and the collector
ash during one test period. The polychlorinated biphenyls (PCS) were
apparently formed during the combustion of the coal. None of these were
found in the coal, but they were found in all of the ash streams.
The vaporization-condensation postulate for the enrichment of trace elements
in various effluent streams (which has been supported by all of the studies
discussed) is further corroborated by comparing the flue gas temperatures at
various stages in the combustion process (Figure 10) with the volatility
78
-------
TABLE 29. ANALYTICAL RESULTS OF THE STATION I SAMPLESa(8)
Element
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chlorine
Chromium
Cobalt
Copper
Fluorine
Iron
Lead
Manganese
Magnesium
Mercury
Molybdenum
Nickel
Selenium
Titanium
Silver
Sulfur
Uranium
Vanadium
Zinc
Coal
2.3%
.53
.83
130.
.82
51.
.18
1.76Z
44.
21.
2.1
34.
140.
.40%
4.2
170.
.29%
.13
4.0
9.0
2.2
.11%
.045
.72%
1.3
51.
24.
Clear
Pond
Return
5.0
.024
.0045
.5
.0013
3.2
.0054
790.
28.
.074
.0081
.036
20.
.31
.008
.86
68.
.0005
.035
.025
.048
.1
.0003
785.
.010
.16
.10
Cooling
Tower
Slowdown
2.2
.024
.003
.5
.0036
.27
.001
140.
25.
.056
.026
.24
.91
1.2
.016
.10
37.
.0004
.05
.005
.0037
.1
.0003
.27%
.015
.14
.40
Lime
.30%
.6
.06
<40.
1.2
6.8
.46
53.5
125.
12.
1.4
17.
520.
.12%
11.
77.
.46%
.057
4.5
3.3
.27
87.
.013
29.
7.8
31.
6.3
Bottom
Ash
10.3%
.39
1.3
670.
2.5
160.
1.0
8.66%
140.
67.
7.0
93.
100.
2.51%
7.1
690.
1.20%
.014
3.7
39.
.70
.45%
.11
.11
13.
230.
41.
Bottom
Ash
Sluice
Water
2.4
.041
.0041
.5
.0013
2.5
.0038
790.
28.
.12
.005
.024
16.
.30
.007
.79
68.
.0005
.056
.015
.031
.1
.0004
770.
.0058
.19
.076
Scrubber
Slurry
Solids
10.8%
2.3
5.2
840.
3.2
220.
1.8
11.8%
89.
118.
8.1
155.
820.
2.25*
49.
.102
1.36%
.053
10.
38.
8.7
.40%
.23
1.44%
3.6
268.
190.
Scrubber
Slurry
Liquid
4.8
.036
.0013
.5
.0015
2.8
.0068
910.
28.
.14
.011
.049
20.
.74
.023
.88
62.
.0007
.015
.015
.12
.1
.0005
865.
.0087
.23
.089
Economizer
Ash
10.0%
2.1
3.3
800.
3.2
260.
7.3
11.5%
200.
.114
15.
105.
120.
2.15%
15.
.10%
1.47%
.010
34.
47.
.46
.48%
.093
.30
7.6
275;
57.
Combined
WEP
20.
.002
.026
.5
.0014
.81
.0095
68.
22.
.92
.016
.07
1.22
10.
.061
.27
11.
.004
.43
.12
.020
.96
.0008
2370
.0069
.50
.30
a Values represent the average of duplicate determinations. Values for liquid samples are reported as ug/ml and solids samples as ppm on a dry
basis, unless otherwise noted. HEP analysis in 10~8 Ib/scf (60°F, 29.92" Hg).
b
Analysis from reserve WEP (529).
-------
TABLE 30. ANALYTICAL RESULTS OF THE STATION II SAMPLES a (9)
Element
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chlorine
Chromium
Cobalt
Copper
Fluorine
Iron
Lead
Manganese
Magnesium
Mercury
Molybdenum
Nickel
Selenium
Titanium
Silver
Sulfur
Uranium
Vanadium
Zinc
Coal
.71%
.16
2.5
460.
.29
31.
<.l
1.09%
9.4
9.3
1.5
31.
67.
.21%
2.3
24.
.15%
.14
.64
2.1
1.6
565.
.048
.49%
.89
20.0
4.1
Inlet
Sluice
Water
<.l
.0023
<.0001
<.6
<.002
.17
<,002
57.
8.6
<.053
<.003
.012
.45
.12
.017
.034
15.
.08
<.0002
<.02
.0017
<.l
<.0003
14.
.0084
0.058
.39
Precipitator
Ash
12%
2.3
48.
.78%
5.6
550.
1.2
19.5%
47-
116.
27.
460.
1130.
2.95%
22.
406.
2.80%
<.010
8.4
37.
6.8
.96%
.90
.80%
5.8
295.
77.
Sluice
Ash
10.9%
<.08
1.4
.52%
4.1
240.
<.8
15.1%
<1.
18.
230.
19.
4.06%
11.
310.
2.06%
<.010
3.5
27.
.35
.91%
.11
910.
5.0
190.
156.
Sluice
Ash
Filtrate
9.2
.0038
<.0001
<.6
<.002
.49
<.002
113.
15.
<.053
<.003
.022
.70
.01
.006
.016
16.
<.0004
.015
<.02
.0038
<.l
<.0003
108.
.0044
0.071
.0084
.Combined
WEP
31.
.0029
.0007
.26
.0042
.92
.0016
55.
29.
.59
o015
.12
2.7
9.5
.060
.18
8.1
.017
.031
.29
.12
2.2
.0003
2380.
.0031
.26
.084
Values represent the average of duplicate determinations. Values for liquid samples are
reported as ug/ml and solids samples as ppm on a dry basis, unless otherwise noted. WEP
values are reported as 1CT8 Ib/scf (60°F, 29.92" Hg).
80
-------
3ABLE 31. ANALYTICAL RESULTS OF THE STATION III SAMPLES a (10)
00
Element
Aluminum
Antimony
Arsenic
Barium
Beryllium
Boron
Cadmium
Calcium
Chlorine
Chromium
Cobalt
Copper
Fluorine
Iron
Lead
Magnesium
Manganese
Mercury
Molybdenum
Nickel
Selenium
Titanium
Silver
Sulfur
Uranium
Vanadium
Zinc
Coal
.in
.40
8.0
440.
.60
150.
.20
1.38%
55.
13.
.75
10.5
57.
.75%
.86
.37%
79.
.074
2.0
5.4
1.3
350.
.034
1.44%
1.5
15.
7.8
Ash
Sluice
Water
Inlet
.42
.018
.006
<.5
.0014
.26
.0003
35.
12.
<.053
.0003
.0084
.21
.43
.015
26.
.082
<.0005
.033
.006
.0012
<.l
<.0003
68.
.0022
<.005
.013
Bottom
Ash
8.79%
.8
20.
.57%
5.3
520.
.87
13.0%
88.
95.
10.
50.
<10.
6.54%
<.8
3.71%
720.
<.010
18.
23.
.25
.35%
.11
95.
3.2
140.
18.
Bottom
Ash
Water
Sluice
1.7
.034
.0087
<.5
.0017
.25
.0011
43.
16.
<.053
.0041
.014
.25
2.1
.024
26.
.055
<.0005
.016
.001 '4
.0011
<.l
<.0003
74.
.0035
<-005
.013
Economizer
Ash
8.48%
.56
126.
.83%
8.8
740.
1.8
12.0%
119.
121
12.
94.
65.
6.69%
8.3
3.77%
900.
.12
44.
36.
.14
.38%
.32
.13%
11.
110.
140.
Economizer
Ash
Sluice Water
.58
.021
.0012
<.5
.003
2.4
.0012
46.
17.
<.053
.0039
.008
.21
1.4
.025
24.
.096
<.0005
.012
.007
.0012
<.l
<.0003
77.
.0044
<.005
.028
Cyclone
Ash
7.44%
.79
188.
.77%
8.3
.16%
2.9
13.1%
135.
86.
13.
145.
670.
5.76%
8.2
3.63%
750.
.17
61.
38.
9.5
.30%
.75
.87%
12.
86.
120.
South
Duct
WEP
730
.18
.67
<5.8
.027
.71
.054
1800
29
3.5
.28
1.9
29
930
.28
7.1
450
,080
2.1
2.3
.31
15
<.0031
7000
.15
2.5
3.5
North
Duct
WEP
440
.13
1.3
5.3
.021
.34
.059
1100
43
3.6
.21
1.6
33
550
.33
4.3
260
.086
3.7
3.0
.26
18
<.003
7400
.086
2.2
2.2
Values represent the average of duplicate determinations. Values for liquid samples are reported as ug/ml and solids samples as ppm on a
dry basis, unless otherwise noted. WEP values are reported as W~° Ib/scf (60°F, 29.92" Hg).
-------
TABLE 32. TOLLUTANT CONCENTRATION (ppm)a IN COAL, ASH, AND FLUE GAS STREAMS AT WIDOWS CREEK
STEAM PLANT (29)
Oo
Pollutant
Run
Coal
Bottom
ash
Superheater
ash
Inlet Dust
fly ash collector ash
Outlet
fly ash
Trace elements (cations)
Antimony
Arsenic
Barium
Beryllium
Cadmium
Chromium
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4.
Avg.
2
3
4
Avg.
< 1.3
0.7
< 1.2
< 1.1
13.0
13.5
16.3
14.3
< 167
< 173
< 165
< 168
1.6
1.5
1.4
1.5
1.25
0.31
1.40
0.99
24
24
23
24
1.3
1.4
1.3
1.3
5.6
7.6
4.2
5.8
905
844
444
731
8.0
7.4
6.5
7.3
0.50
2.01
0.74
1.08
125
132
116
124
0.31
1.3
1.1
0.90
12.1
3.2
5.7
7.0
1,119
592
715
809
6.4
5.6
6.2
6.1
1.46
1.35
1.98
1.60
109
105
130
115
0.55
< 1.0
< 1.3
< 0.95
8.2
8.1
8.8
8.4
1,054
604
986
881
8.2
7.7
8.2
8.0
4.42
4.18
10.73
6.44
296
168
153
206
y
1.4
0.32
< 0.9
b/
b/
b/
y
1,213
916
1,367
1,165
7.2
6.8
9.7
7.9
2.89
1.14
2.00
2.01
133
191
128
151
1.54
1.36
1.5
1.5
7.4
5.5
12.0
8.3
1,028
1,262
931
1,074
10.0
8.5
9.5
9.3
6.29
3.88
14.09
8.09
316
170
174
220
(continued)
-------
TABLE 32. (continued)
POLLUTANT CONCENTRATION (ppm)a IN COAL, ASH, AND FLUE GAS STREAMS AT
WIDOWS CREEK STEAM PLANT (29)
oo
(JO
Pollutant
Cobalt
Copper
Lead
Manganese
Mercury
Nickel
Run
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
Coal
1.84
1.51
0.99
1.45
10
12
9
10
3.68
2.26
5.23
3.72
24
30
51
35
1.88
1.91
1.93
1.91
18
16
12
15
Bottom
ash
5.74
1.95
3.20
3.63
51
48
45
48
6.94
12.3
5.07
8.10
125
377
184
229
< 0.541
< 0.489
< 0.502
< 0.51
45
84
58
62
Superheater
ash
5.86
4.45
3.93
4.75
54
46
45
48
11.9
10.4
9.41
10.6
217
265
326
269
< 0.58
6.90
46.4
< 18.0
108
94
102
101
Inlet
Dust
fly ash collector ash
7.09
6.49
4.36
5.98
75
65
64
68
21.8
26.1
48.2
32.0
153
222
371
249
16.7
23.8
18.3
20.0
178
128
97
134
10.5
6.87
6.41
7.93
59
74
39
57
21.7
11.6
11.5
14.9
169
287
268
241
< 1.21
< 1.17
< 1.17
< 1.18
88
98
60
82
Outlet
fly ash
3.61
2.78
4.68
3.69
81
70
72
74
18.7
29.9
61.2
36.6
164
154
285
201
23.3
2.2
25.4
17.0
206
86
86
126
(continued)
-------
TABLE 32 (continued).
POLLUTANT CONCENTRATION (ppm)a IN COAL, ASH, AND FLUE GAS STREAMS AT
WIDOWS CREEK STEAM PLANT (29)
oo
•f=-
Pollutant Run
Selenium 2
3
4
Avg.
Tellurium 2
3
4
Avg.
Tin 2
3
4
Avg.
Titanium 2
3
4
Avg.
Vanadium 2
3
4
Avg.
Zinc 2
3
4
Avg.
Coal
< 6.1
< 6.1
6.0
< 6.1
< 30
< 30
< 30
< 30
1.73
1.70
1.65
1.69
1,090
833
758
895
61
61
64
62
36
17
111
55
Bottom
ash
< 5.5
< 5.9
< 5.4
< 5.6
62
41
26
43
2.83
1.81
1.45
2.03
6,900
5,520
6,010
6,150
272
419
369
353
68
275
107
150
Superheater
ash
< 6.2
< 5.7
< 5.5
< 5.8
30
< 27
< 27
< 28
2.11
1.59
2.08
1.93
5,430
5,480
5,200
5,370
229
215
342
262
133
110
186
143
Inlet
Dust
fly ash collector ash
27.9
24.1
27.5
26.5
31
< 30
< 30
< 30
3.04
3.31
2.07
2.81
6,420
6,990
5,930
6,450
308
238
478
341
163
201
691
352
b/
b/
< 12~. 5
< 12.5
30
31
28
30
1.74
3.48
3.45
2.89
5,150
6,260
3,940
5,120
275
190
240
235
154
131
164
150
Outlet
fly ash
< 18.9
< 13.1
18.2
< 16.7
< 35
35
29
< 33
1.69
2.38
1.69
1.92
6,840
7,410
6,400
6,890
359
262
623
415
212
150
736
366
(continued)
-------
TABLE 32 (continued).
POLLUTANT COSfCENTEATION (ppm)a IN COAL, ASH, AMD FLUE GAS STREAMS AT
WIDOWS CREEK STEAM PIAWT (29)
CD
vn
Pollutant
Minor elements (cations)
Calcium
Iron
Sulfur
Anions
Chloride
Fluoride
Nitrate
Run
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
Coal
11,200
11,300
13,500
12,000
19,500
23,600
26,600
23,200
26,000
38,500
39,500
34,700
396
43
18
152
135
124
104
121
Bottom
ash
9,500
49,300
45,500
34,800
120,000
290,400
288,400
212,900
900
2,200
1,700
1,600
92
91
76.5
87
9.0
10.6
12.3
10.6
15.5
17.7
14.7
16.0
Superheater
ash
24,100
35,000
49,000
36,000
190,500
258,700
313,900
254,400
4,000
4,200
4,800
4,330
27.5
37
88
51
43.0
42.8
40.7
42.2
34.0
28.6
18.9
27.2
Inlet
fly ash
9,200
18,700
40,900
22,900
95,500
156,600
172,600
142,600
3,400
808
2,260
2,160
796
564
512
624
178
307
57.6
181
Dust
collector ash
10,500
18,900
32,200
20,500
84,600
188,700
116,500
129,900
11,000
3,000
3,950
5,980
62
31
12
35
45.5
22.5
20.6
29.5
42.1
27.5
33.2
34.3
Outlet
fly ash
7,100
17,200
34,700
19,700
84,200
131,000
124,000
113,000
1,335
125
332
597
830
559
624
671
103
88.8
64.9
85.6
(continued)
-------
TABLE 32 (continued).
POLLUTANT CONCENTRATION (ppm)a IN COAL, ASH, AND FLUE GAS STREAMS AT
WIDOWS CREEK STEAM PLANT (29)
Pollutant
Sulfate
c/
Oreanics—
PCM (1)
PCM (2)
POM (3)
PCB's (all)
a/ Parts per million by
b/ No sample left.
c/ PCM compounds:
Run
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
2
3
4
Avg.
weight .
Coal
2.5
9.6
2.1
4.7
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Bottom
ash
116
1,090
818
675
0.2
ND
ND
< 0.2
0.2
ND
ND
< 0.2
0.2
ND
ND
< 0.2
0.04
ND
0.02
0.02
Superheater
ash
7,130
6,580
7,430
7,050
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.08
0.06
0.12
0.09
Inlet Dust
fly ash collector ash
5,570 2,110
7,000 2,520
8,400 3,510
6,990 2,710
0.2
0.2
0.2
0.2
ND
ND
ND
ND
ND
ND
ND
ND
0.16
0.04
0.02
0.07
Outlet
fly ash
3,970
4,310
8,020
5,430
(1) 7,12-Dimethylbenz[aJanthracene
(2) 3,4-Benzopyrene
(3) 3-Methylcholanthrene
Mote: ND - None detected.
-------
oo
(V
3
-o
2800
2400 k
2000 r-
1600
1200
•800
400
Burner-
Furnace
Boiler/Economizer
/Air-heater
j
Precipiiator
Srack
Figure 10. Temperature history of flue gases. (20)
-------
index of the trace elements (Table 33). Usually the more volatile the ele-
ment, the more likely that it will be emitted from the plant as an uncon-
densed vapor or as a fine particulate. The only element which failed to
follow this postulate is beryllium. According to the Widows Creek report,
it was the only potentially hazardous element emitted in the gas stream at
a concentration near its threshold limit value.
The reports discussed above concluded that certain elements are enriched in
the smaller particles produced by the combustion of coal. These fine, more
enriched particles are also the ones most easily passed through particulate
control devices. Natusch et al.4 reported that many of the elements are
enriched 100-1000 fold over their natural abundance in the earth's crust.
The major portion of this enriched particulate mass occurs in the 0.5-10.0
micron particle diameter range. Particles of this size are commonly inhaled
and deposited in the human respiratory system.
Lee and von Lehmden36 studied trace metal pollution in the environment.
Table 34 shows the concentration and the particle size of trace metal parti-
cles in urban air. Airborne metals which were measured at concentrations
greater than 1 yg/m3 included iron, lead, zinc, and magnesium. These ele-
ments are all emitted from coal-fired power plants as well as from certain
other industrial sources. Also, examination of the trace metals emitted in
flyash (see Table 35) shows that some metals, such as cadmium, chromium,
manganese, and lead, are more concentrated in the smaller particles emitted.
Since these fine particulates are more apt to be inhaled than the larger
ones, they may present a greater environmental hazard. Table 36 shows the
distribution of flyash sampled at the inlet and outlet of the collector.
The outlet flyash contains a much greater proportion of the small particu-
lates than the inlet flyash. Thus, the smaller particles in which trace
elements are generally more concentrated are also the ones most easily
passed through collectors and the ones which are more respirable. It is the
combination of these characteristics which makes fine particulates a source
of growing concern.
METHODS FOR CHEMICAL ANALYSIS OF COAL AND FLYASH
Since the above discussions on chemical characteristics of coal and ash
include values determined by a variety of analytical methods, a review and
comparison of these methods is needed.
Early chemical analyses of coal and its ashes was limited to the major ele-
ments (Si, Al, Fe, Ca, S, and Mg). In 1935, Goldschmidt and Peters of the
United States Geological Survey (USGS) performed the first trace element
analysis of U.S. coal. However, it was not until 1948 that the USGS began
an ongoing program for the sampling and analysis of coal for trace elements.
The early lack of trace element analysis resulted from the difficulty of
applying the classical wet chemistry methods of analysis to trace constitu-
ents. However, the advent of newer techniques of instrumental analysis has
made analysis of trace elements more feasible. The term trace element is
here defined as any element whose concentration is 1000 ppm (0.1 percent)
or less.
88
-------
33 . VOLATILITY OF TRACE ELEMENTS IN COAL (29)
Volatility Index and Temperature^-^
1
< 300°F
mercury
fluorine
thallium
antimony
2 3 4
300-850°F 850-1300°F
c/
selenium zinc— copper
arsenic - - - - cobalt
c/
- - - - barium— lead
chlorine manganese
tellurium nickel-
chromium—
cadmium—
5
> 1300°F
beryllium
boron
titanium
vanadium
tin
a/ Entries above dashed lines are from Occurrence and
~~ Distribution of Potentially Volatile Trace Elements
in Coal.
b/ Temperature ranges within which volatilization of an
element occurs.
_c/ Preferentially concentrated in fine particles of fly
ash (pulverized firing).
jd/ Concentrated in crust of moderate-sized particles of
fly ash (pulverized firing).
e/ Large percentage to bottom ash (pulverized firing).
89
-------
VD
O
TA3LE 314.. CONCENTRATION AND SIZE OF TRACE
METAL PARTICLES IN URBAN AIR (36)
Metal
Fe
Pb
Zn
Cu
Ni
Mn
V
Cd
Ba
Cr
Sn
Mg
Concentration,
yg/m3
0.6-1.8
0.3-3.2
0.1-1.7
0.05-0.9
0.04-0.11
0.02-0.17
0.06-0.86
0-0.08
0-0.09
0.005-0.31
0-0.09
0.42-7.21
MMD,aum
2.35-3.57
0.2-1.43
0.58-1.79
0.87-2.78
0.83-1.67
1.34-3.04
0.35-1.25
1.54-3.1
1.95-2.26
1.5-1.9
0.93-1.53
4.5-7.2
Particles
-------
TABLE 35. TRACE METALS IN FLY ASH AS A
FUNCTION OF PARTICLE SIZE (36)
Element
Al
B
Be
Cd
Cr
Cu
Fe
Mn
Ni
Pb
V
Concentration, ppm
25 ym
67,000
300
2
<5
130
150
40,000
200
300
300
200
12.5 ym
54,300
500
1
<5
130
150
59,000
240
200
200
200
10 ym
57,300
500
2
<5
130
200
43,500
290
200
300
200
3.5 ym
63,600
500
2
<5
300
200
35,500
390
300
300
200
1.5 ym
59,300
500
2
100
300
200
32,300
500
300
500
200
*a
Sample collected from a coal-fired steam power plant and analyzed by neutron
activation and spark source mass spectrometry.
-------
TABLE 36. PERCENT PARTICLE MASS AS FUNCTION OF SIZE & (3)
Th'ameter
u
Above 30
20-30
10-20
5-10
1-5
0-1
Sample
Set A
Sample Set B
Total
Particulate
Tn
let
24
21
38
13
3
1
let
5
6
17
20
38
14
Fe
Tn
let
15
6
15
16
30
18
let
8
5
9
14
45
19
V
let let
6 0
7 0
17 12
20 10
31 43
19 35
Cr
let let
16 0
14 0
26 0
7 0
25 20
12 80
Ni
let let
40 0
4 0
18 13
23 43
7 30
8 14
Mn
let let
0 0
8 0
89 0
33 0
0 0
0 0
Pb
let let
18 0
6 0
20 1
6 9
29 40
21 50
Sb
let let
0 0
0 0
0 0
0 0
0 38
100 62
Cd
let let
12 12
11 8
22 10
15 20
5 30
35 20
Zn
let let
15 2
6 6
21 30
26 10
17 8
15 44
Total
Particulate
In-
let
21
19
31
19
7
3
let
5
6
18
19
37
15
Seb
let let
7 8
5 6
9 16
19 18
9 22
51 30
Samples collected at the inlet and at the outlet of an electrostatic precipitator control device.
bAnalysis by neutron activation.
-------
Description of Methods
Instrumental methods often used for the determination of trace elements in
coal or flyash include atomic absorption spectrometry, neutron and photon
activation analysis, spark-source mass spectrometry, optical emission spec-
trometry, visible and ultraviolet absorption spectrophotometry, X-ray
fluorescence, voltammetry, and potentiometry (ion-selective electrodes),
among others.
These methods may be separated generally into two categories. One category
includes methods for the determination of more than one element in a single
sample. This is especially convenient when large numbers of samples must be
analyzed for several elements. Examples of these methods are neutron activa-
tion, photon activation, X-ray fluorescence, spark-source mass spectrometry,
and optical emission spectroscopy which includes plasma arc emission
spectroscopy with multi-element reader.
The second category includes methods which cannot be easily used for multi-
element analyses on an individual sample. Therefore, many of these methods
may require large quantities of sample if more than a few elements are to be
determined. These methods, which include atomic absorption spectroscopy,
potentiometry, voltammetry, and absorption spectrophotometry, require sample
preparation for the coal and flyash matrices. This sample preparation,
usually the wet or dry ashing of coal or the dissolution of flyash through
acid treatment or fusion, offers opportunity for sample contamination. How-
ever, with the use of appropriate standards and/or the method of standard
additions, detection limits can be good. Precision depends largely on the
individual analyst's skill. An additional advantage of methods in this
category is that the equipment required is comparatively inexpensive.5
Let us first consider the methods in this latter group. In atomic absorp-
tion spectroscopy (AAS), for example, the sample in solution is atomized by
a flame or other energy source, where it produces atomic vapor of the element
being analyzed. Monochromatic light which is the same wavelength as that of
the required element is then passed through the sample vapor. The atoms
present in the ground state (unexcited state) of the vapor absorb radiation
from the monochromatic light source in proportion to their concentration
present in the sample. 6
Types of interference encountered in using atomic absorption spectroscopy
for coal or ash samples include interelement or chemical interferences,
matrix effects (which stem from the large concentrations of acids and solids
in solution), and molecular absorptions (which predominately occur from
species such as SrO or CaOH and result in a positive error in the absorption
measurement).^ 7
Natusch et al.4 determined Pb, Tl, Ni, As, Cd, and Be in flyash by flame
atomic absorption and found results in good agreement with those from spark-
source mass spectrometry, except for Tl. Selenium was converted to H Se and
then analyzed, following the method of Schmidt and Royer.4 Using standard
addition calibrations, a precision of +_ 10 percent for all analyses could
be obtained.
93
-------
Flameless atomic absorption spectroscopy (FAAS) achieves better sensitivity
for some elements than does atomic absorption spectroscopy. Information on
the background concentration for solvent molecular scattering is necessary
in addition to separation and preconcentration of the samples. Improved
methods for atomic absorption spectroscopy are presently being developed to
make possible the use of this technique for mercury, cadmium, selenium, and
arsenic. These improvements include larger samples and special vaporization
techniques.16
Polarography and fluoride-ion selective electrode are other methods which
normally require individual samples for analysis of individual elements.
Polarography is not used extensively for trace-element analyses in coal or
flyash, although its sensitivity for several elements (for example, cadmium)
makes it useful for trace analyses after interfering ions are separated.
Trace fluoride determinations are commonly made by fluoride-ion selective
electrode, an inexpensive and simple application of potentiometry. A detec-
tion limit of 10 ppm for fluoride in whole coal was obtained by Ruch et al.38
Although extensive sample preparation and digestion was required, precision
for repeated measurements was good.5
Voltammetry is an electrochemical method in which application of a negative
voltage is used to plate metal ions acid-extracted from the sample onto an
electrode. The electrode potential is then varied linearly in an anodic
direction, which produces a sharp current peak proportional to the
concentration in the sample.39
Many methods in the first-mentioned category, those capable of multiple
element analysis on a single sample, have another important advantage as
well as the multiple element analysis. Since the organic material in the
coal is the major source of interference in many trace element determina-
tions, procedures to reduce or remove this interference through ashing or
destruction of the sample are common in many analytical methods. These pro-
cedures are expensive, time consuming, and introduce a potentially serious
source of error. Some of the newer methods contained in this category,
however, do not require ashing or destruction of the sample and, therefore,
eliminate this significant source of error.
Instrumental neutron activation analysis (INAA) is one such non-destructive
method of analysis. In this method, the sample is irradiated in a nuclear
reactor directly, without chemical dissolution or extraction. When bom-
barded thus with slow neutrons, many elements give rise to radioactive
isotopes. When the other components of the sample do not interfere, it
is possible to identify the elements present and their concentrations from
measurement of intensities of different peaks in the gamma ray spectrum.
This method offers high sensitivity and the capability for multi-element
determinations. The Oak Ridge National Laboratory study at the Tennessee
Valley Authority's Allen Steam Plant reported results by instrumental neu-
tron activation analysis with accuracies of 5 to 10 percent for submicrogram
quantities. Gordon reported accuracies of 2 to 3 percent in trace element
studies at the Chalk Point Station using this method. Lf°
-------
In a recent study, four laboratories measured the concentrations of 37
elements in National Bureau of Standards standard coal samples (SRM 1632)
and 41 elements in the standard reference for flyash (SRM 1633), using
instrumental neutron activation analysis. Their conclusions were as follows:
"In cases where comparisons can be made, both the accuracy and interlabora-
tory dispersion of results obtained in the analysis of coal and flyash by
nuclear methods are generally superior to other methods using in the round-
robin study. We suspect that the major reason for this performance of the
technique is the fact that virtually no pretreatment of the samples is
needed. Thus, we avoid the difficulties encountered in dissolving samples
that can occur with the use of other methods such as AAS: loss of volatile
species, incomplete dissolution of certain fractions, loss of elements on
insoluble residues or container walls, and contamination of samples by
impurities in reagents or container materials. Also, because of the long
ranges of projectiles and emitted X-rays, the nuclear methods are almost
completely free of matrix effects."11
For a few elements, the sensitivity of neutron activation can be much
improved by radiochemical separations to remove those elements which have
interfering radioactivities. Although these separations allow more oppor-
tunity for sample contamination, usually limit the analysis to one element
per sample, and are slower, it is possible to obtain high precision and
accuracy. Radiochemical separations on low-temperature coal ash samples to
determine As, Se, Zn, Cd, and Ga were carried out by Ruch et al.38 However,
there are cases in which INAA gives a completely false measurement due to
the snythesis of elements in nuclear bombardment. For example, National
Bureau of Standards studies on strontium in granite represent one such
case.16
Instrumental photon activation analysis (IPAA), a nuclear method similar to
instrumental neutron activation analysis, is one by which the elements As,
Ni, Pb, Sb, Ni, Br, and I can be easily measured in the submicrogram range.
A significant drawback to this method, however, is that it requires the
bremsstrahlung produced by an eltctron accelerator for irradiation of the
sample.5
Spark-source mass spectrometry (SSMS) is another survey method with good
sensitivity. In this method the sample, compounded in a silver or graphite
electrode, is ionized with a high intensity spark. A determination is then
made of the intensities of the ions of different mass-to-charge ratios; they
define different radial paths in a magnetic field and, therefore, come to a
focus at varying points along a photographic plate positioned on the focal
plane of the magnetic analyzer. Other modes of detecting individual iso-
topes include scanning of the ion species at a collector slit located at
the principal focus or use of electric static peak switching with static
integration.41
The method of spark-source mass spectrometry has several advantages,
including high sensitivity, comprehensive element coverage, and linearity.
Determinations may be made for many elements at concentrations as low as
1 ppb; also, semi-quantitative determinations as low as 100 ppb for some
95
-------
elements can be performed by electrical scanning. This technique allows
detection of all elements simultaneously during an electrical scan, includ-
ing interstitial gases, with minimal spectral overlap, matrix effects, or
interelement effects. Also, this method exhibits linear response for ionic
species of any element with the ion intensity being proportional to the
concentration of that element in the sample. 1
Although detection limits with this method for most elements in coal and
flyash are in the parts-per-billion range, accuracy may be only 4^ 50 percent,
varying with the concentration of interferents, as well as with data inter-
pretation. Accuracy may be improved with the use of standards or with the
use of stable isotope dilution (SSMS-ID). For elements having stable iso-
topes, the accuracy of this method is restricted only by the + percent homo-
geneity of photographic emulsion on which ion intensity is recorded.5
X-ray fluorescence spectroscopy (XRF) involves production of characteristic
fluorescence spectra by irradiation of the sample directly with X-rays. For
analyzing air pollution particulates, Birks^2>1+3 cites the following advan-
tages for this method: no sample preparation is required for filter collec-
tions; elements of atomic number 11 and greater can be analyzed with fairly
uniform detectability; the technique is nondestructive; and several elements
can be determined at one time with available commercial equipment at fairly
low cost. Although this method does not have the submicrogram sensitivities
obtainable by instrumental neutron activation analysis or spark-source mass
spectrometry—isotope dilution, its detection limits may be improved by
using preconcentration techniques or standard reference materials. For
example, precisions of 10 percent or less for microgram quantities of eight
trace elements in coal and ash were obtained by Ruch et al., using X-ray
fluorescence.38
Optical emission spectroscopy involves excitation of the sample in a spark
or arc to produce line spectra of the elements present.^ Use of precon-
centration techniques and/or standards is required here to obtain sensitiv-
ity similar to that of instrumental neutron activation analysis or spark-
source mass spectrometry—isotope dilution. Direct-reading photoelectric
spectrophotometers offer both faster analyses for optical emission spectros-
copy and somewhat greater precision than does use of photographic plates.
Ruch et al.38 achieved precision of less than 10 percent for nine elements
using direct-reading detection and precision of from 9 to 30 percent on the
same samples using photographic detection.5
The decision on which of the above methods to use for chemical analysis of
trace constituents involves consideration by the investigator of several
factors, including the following:
1. Performances of the various methods as to accuracy, precision, and
detection limits.
2. Cost and time limitations of the methods.
3. Matrix effects of the methods.
4. Sample size requirement.
5. Degree of sophistication and reliability required of instrumenta-
tion.
96
-------
6. Degree of training required for operation of the instrumentation.
The analytical method chosen in a study thus may depend on the individual
requirements and resources of the investigation.
Comparisons of Methods
The previous discussions on the various analytical techniques indicate the
capabilities and uses of individual methods. However, it is important to
realize that data from studies using different methods for analysis are not
strictly comparable betause of differences in performance capabilities among
these methods. To make the evaluation of results from different studies more
feasible, several instigations have been made to compare the analytical
performances of several methods on the same samples.
Von Lehmden et al.39 undertook the comparison of six analytical methods.
In this study, nine laboratories were asked to determine the concentration
of 28 elements in portions of the same coal and ash samples. The analytical
methods employed were neutron activation analysis, atomic absorption, opti-
cal spectrometry, anodic stripping voltammetry, spark-source mass spectro-
metry, and X-ray fluorescence. The determinations from the different
laboratories were evaluated to assess the comparability of the various
methods as applied to these matrices. Table 37 shows the results for the
coal samples, and the ash results are given in Table 38. The following
results were obtained from this study. Only definitive concentrations were
used for these conclusions (no less-than values were considered).
1. For at least eight trace elements in coal and ash, reported concen-
trations varied by more than one order of magnitude. For coal,
these elements included Mn, Sb, Se, F, Li, Sn, K, and Ba. For ash,
these elements were As, V, Zn, Se, Li, Ag, Sn, Na, and Mg.
2. Reported concentrations for three elements (Se, Li, and Sn), varied
by more than an order of magnitude in both coal and ash matrices.
3. Agreement was within an order of magnitude in both matrices for
only 9 of the 28 elements. These nine were Si, Ca, S, Sr, Fe, Cr,
Ni, Be, and B.
4. Standard samples must be prepared and standard methods of analysis
must be developed for this material.
In an effort to resolve the analytical problems, the National Bureau of
Standards (NBS), in cooperation with the Environmental Protection Agency,
prepared Standard Reference Material (SRM) samples for coal (SRM #1632)
and ash (SRM #1633). Portions of these samples were sent to 85 labora-
tories for analysis. "For many of the elements measured, there were sur-
prisingly wide variations of concentrations reported by the participating
laboratories far outside the uncertainties usually quoted for the techni-
ques used. For this reason, it is clear that the standards are badly needed
so that laboratories can check their procedures for the elements they claim
to be able to measure."11
-------
TABLE 37- COAL ANALYSIS COMPARISON FOR TRACE ELEMENTS
BY LABORATORY AND BY ANALYTICAL METHOD (39)
Laboratory
Code
Analytical
Method
Elements
analyzed,
1
SSMSa
3
SSMS
6 1
a SSMSa OESb
3
2
OESb NAAC
3
1+
NAAC NAAC
5
NAA
3
c NAAC
3
AAS
ppm
(by weight)
Hg
Be
Cd
As
V
Mn
Ni
Sb
Cr
Zn
Cu
Fb
Se
B
F
Li
Ag
Sn
Fe
Sr
Na
<2.
0.1+
6.
2.
10.
20.
<1+0.
0.6
<30.
<100.
10.
-------
TABLE 37. COAL ANALYSIS COMPARISON FOR TRACE ELEMENTS
BY LABORATORY AND BY ANALYTICAL METHOD (39)
Laboratory 1 3 6 1 3 23^550
Code ? J 3
Analytical SSMSa SSMSa SSMSa OESb OESb NAAC NAA° NAAC NAAC WAC AAS
Method
Elements
analyzed,
ppm
(by weight)
K
Ca
Si
Mg
Ba
100.
10,000.
6000.
2000.
J+oo.
50.
10,000.
10,000.
700.
30.
200.
5,800.
10,000.
2000.
no.
150.
8,000.
3,000.
600.
500.
20.
10,000.
20,000.
100.
200.
NA
NA
NA
2600.
NA
2200.
5500.
NA
NA
220.
280
7070.
NA
920.
430.
NA
NA
NA
NA
NA
100
NA
NA
1000.
<2.0
NA
NA
NA
NA
NA
a - Analysis on sample direct
b - DC ARC on sample direct
c - Instrumental NAA
d - Dissolution followed by flameless AAS
Analysis'code: NAA, neutron activation analysis
SSMS, spark source mass spectrometry
OES, optical emission spectrometry
AAS, atomic absorption spectrometry
NA, no analysis
99
-------
TABLE 38. FLYASH ANALYSIS COMPARISON FOR TRACE ELEMENTS BY LABORATORY AND BY ANALYTICAL METHOD (39)
O
O
Laboratory code 1
Analytical method SSMSb
Elements
Analyzed,
ppma
Hg
Be
Cd
As
V
Ml
Hi
Sb
Cr
Zn
Cu
Fb
Se
B
F
Li
Ag
Sn
Fe
Sr
Na
K
Ca
Si
Mg
Ba
1
7
3
1*0
250
300
100
10
200
200
100
200
10
500
30
20
1
6
High
150
2000
High
High
High
10,000
200
1
SSMS1''0
0.1*
1
6
100
300
150
100
1*0
100
70
150
200
15
200
10
60
2
15
High
200
2000
High
High
High
10,000
600
3.
SSMSD
2
5
2
15
200
300
100
NA
100
1000
200
100
NA
300
6
SSMSb
0.1
7
2.3
2.8
290
170
U5
5.6
330
330
1*5
180
0.77
190
100 max 60
150
NA
NA
10$
200
500
1.$
lt.0'
10$
5000
700
190
o.oi*
1-9
5.3$
69
6600
1.7$
% 1.3$
major
1*1*, 000
110
1
OESd
1
5
50
100
2000
500
300
50
500
100
300
100
NA
300
NA
20
3
20
20$
200
3000
2$
5$
20$
5000
200
OES°'d
1
1*
100
200
1*00
200
50
100
100
200
200
200
NA
300
NA
100
2
100
10$
200
1*000
2$
5$
15$
1*000
300
3
OESa
NA
7
NA
50
200
500
300
NA
300
200
300
200
NA
500
NA
300
1
NA
5.0$
500
3000
0.5$
3.0$
20$
5000
500
DRES6
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
HA
NA
10.5$
NA
ll*00
NA
3.7$
NA
1*000
NA
DRES6
NA
3
NA
NA
180
NA
NA
NA
80
350
NA
1*1*0
NA
HA
NA
HA
NA
HA
13$
1*00
NA
HA
3-7$
NA
2200
NA
NAAf
1
NA
NA
30
290
317
NA
9.2
108
NA
NA
NA
8.2
HA
NA
NA
NA
HA
17.5$
520
2700
HA
HA
NA
13,700
NA
NAAf
18
NA
NA
70
2l*7
291*
HA
7
100
NA
NA
NA
1*0
NA
NA
NA
NA
NA
18.3$
NA
2300
1.5$
2.2$
NA
7000
200
NAAf
0.3
NA
90
5U
382
369
NA
19
130
HA
33
HA
12
NA
NA
NA
NA
NA
18.1$
180
21*50
3.1$
3.9*
NA
3000
1*10
NAAf
NA
NA
NA
1*0
250
250
NA
NA
NA
NA
NA
NA
NA
HA
NA
NA
NA
NA
26$
1000
3500
2.5$
HA
HA
1*000
1*00
1
AAS
0.21
NA
NA
NA
300
NA
100
NA
150
600
90
95
NA
NA
NA
NA
NA
NA
17.8$
NA
2800
2.0$
>*.7$
19-5$
6000
NA
a ppm by weight, higher concentrations are specified as percent($). b Analysis on sample direct, c Duplicate sample submitted for SSMS and OES
analysis only, d DC arc on sample direct, e Dissolution followed by RF spark analysis, f Instrumental NAA. Analysis code: NAA, neutron acti-
vation analysis; SSMS, spark source mass spectrometry, OES, optical emission spectrometry; DRES, direct reading emission spectrometry; AAS, atomic
absorption spectrometry; NA, no analysis.
-------
In a study by Ondov et al.,11 four participating laboratories measured the
concentrations of 37 elements in the NBS standard coal sample and 41 ele-
ments in flyash. The analyses were performed by instrumental neutron acti-
vation, photon activation and natural radioactivity. The latter method
was used by one laboratory to determine K, Th, and U. The results of the
measurements from these four laboratories and those from a study by
Faulkerson et al.2 are given in Table 39 for coal and Table 40 for ash.
Both the accuracy and interlaboratory dispersion of results for these methods
are generally superior to those for the other methods discussed.
While the results of the activation analysis from this study were good,
there is still a need to develop standard procedures for the other methods
of analysis. To this end, a task group under the D-5 committee of the
American Society for Testing and Materials (ASTM) is currently conducting a
round-robin analysis of coal and ash. Work has been essentially completed
on the development of standardized methods for the analysis of some trace
elements (F, Hg, Be, Cr, Cu, Mn, Ni, Pb, V, Zn) and for the major constitu-
ents. It is expected that these methods will appear as ASTM standards in
1978.
101
-------
TABLE 39. ELEMENTAL CONCENTRATIONS IN NBS COAL
(SEM 1632) (pg/g UNLESS % INDICATED) (2,11)
Maryland
Element
Na
Mg($)
Al(#)
Cl
K($)
Ca($)
Sc
Ti
V
Cr
Mn
Fe($)
Co
Ni
Zn
As
Se
Br
Kb
Sr
Ag
In
Sb
Cs
Ba
La
Ce
Sm
Eu
Tb
Yb
Lu
Hf
Ta
W
Th
U
a Twelve
Concn
399+20
0.16+0.02
1.78+0.18
970 +140
0.27+0.01
0.41+0.05
0.47+0.06°
3.7+0.15
960+100
890+200°
37+3
19.7+0.8
41+2
0.86+0.06
5.6+0.2
30+10
5.7+0.2
8 +2C
3.1+0.3
20+4
20+2C
4.3+3-0
1.4+0.1
330+20
11.3+0.5
20.4+0.8
1.83+0.07
0.38+0.03
0.22+0.05
0.7+0.1
0.14+0.01
0.95+0.05
0.21+0.02
0.87+0.10
3.0+0.2
No. of
detns
(9)
(5)
(6)
(12)
(5)
(2)
(3)
(6)
(3)
(3)
(5)
(5)
(6)
(6)
(6)
(4)
(7)
(3)
(5)
(5)
(3)
(6)
(5)
(6)
(5)
(6)
(13)
(6)
(5)
(5)
(6)
(5)
(7)
(5)
(6)
determinations . b
Battelle
Concn (6 detns
unless noted)
420+302
0.23+0.07
1.78+0.08
800+200
0.28+0.01
0.284+0.008
3.^+0.3
1100+200
33+4
19+2
41+6
0.81+0.07
5.2+0.4
16+4
5.7+0.5
3.3+0.4
17+2
19+2
170+20
0.06+0.03
3.7+2.0
1.4+0.1
390+20
10.5+0.5
1.7+0.3
0.28+0.01
0.23+0.06
0.97+0.1
0.23+0.05
3.^+0.6
3.45+0.10b»d
1.4l+0.07b'd
Determined by c
Livermore
Concn
Wash.
(5 detns each) Concn
313+22
2.0+0.1
760+60
0.226+0.008
0.42+0.07
3.9+0.2
1100+100
38+3
19+1
48+3
0.82+0.04
6.0+0.3
5.0+0.7
3.5+0.4
19+2
0.20+0.12
4.1+5.3
327+19
9.1+0.6
18.5+0.7
1.48+0.07
0.32+0.01
0.72+0.06
0.6 +0.3
3.0+0.2
lirect X-ray cc
424+20
1020+90
0.33+0.10
3.9+0.4
1140+60
37.7+1.2
21+2
0.87+0.07
5.9+0.4
20+4
8.0+0.4
3.7+0.4
21.4+0.7
23+2
152+21
3-3+1.1
1.49 +0.12
360+35
11.9+0.5
0.33+0.04
0.97+0.10
0.29+0.05
3.1+0.2
lunting of nati
State
BBS
# of detns ORNL SRM
(5)
(5)
(5)
(21)
W
(16)
(21)
(21)
(10)
(5)
(11)
(5)
(11)
(21)
(15)
(H)
(5)
(10)
(21)
(21)
(16)
oral rac
390
.248
1.90
1000
.29
.44
4.5
930
40+3
21+2
4673
.54
5-9
34
5-5
3-05
14.2
19.5
.07
4.45
1.4
405
10.5
18.5
0.21
•95
.17
3.0
1.26
Lioactivl
800
35+3
20.2+0.5
40+3
.87 +0.03
~6
37+4
5.9+0.6
2.9+0.3
3.0
.ty.
c Determined by instrumental photon activation analysis, d One sample of 100 g was counted
five times for 1000 min each.
102
-------
TABLE
. ELEMENTAL CONCENTRATIONS IN NBS FLYASH
(SRM 1633) (ng/g UNLESS % INDICATED) (2,11)
Maryland
Battelle
No. of Concn (6 detns
Element Concn detns unless noted)
Na
Mg
Al
Si
Cl
K ('
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Hi
Zn
As
Se
Br
Rb
Sr
Y
Zr
In
Sb
I
Cs
Ba
La
Ce
Sm
Eu
Tb
Yb
Lu
Hf
Ta
W
Fb
Th
U
a -
b -
c -
d -
31+00 + 200 (9) 3700 + 200
(%) 1.5 + 0.16 (6) 2.08 + 0.1+3
d) 13.2 + 0.5 (5) 12.6 + 0.1+
d) 21 + 2* (3)
1+2 + 10 (1+)
%) 1.65 + 0.08 (5) 1.71 + o.03b
(%} 1+.2 + 0.1+ (3)
5.3 + 0.5a (3)
27 + 1 (7) 27 + 1
7300 + 1+00 (3) 7600 + 800
7300 + l+00a (3)
251 + 26 (6) 220 + 15
130 + 6 (7) 131 + 8
509 + 20 (8) 1+89 + 11
(%) 6.2 + 0.3 (7) 6.5 + 0-.3
1+1.2 + 1.6 (6) 1+0 + 2
92 + Sa (2)
2l6~+ 25a (3)
60 + 2.5 (9) 6l+5
61.5 + 3.0a (5)
10.3 + l.k (5) 8.8 + 1.2
12 +~~1+
126 + 10a (2) 121+ + 10
1900 + 200
62 + 10a (3)
301 + 20a (2)
7.8 + 0.7 (9) 7.2 + 0.8
7.0 + l.la (3)
2.9 + 1.2a
7.9 + 0.9 (5) 9.9 + 0.8
2700 + 200 (7) 31+00 + 1+00
82+3 (6) 82 + 5°
156~+ 12 (8)
13.8 + 0.6 (8) 12.1+ + o.5c
2.9 +~0.2 (7) 2.3 + 0.1
1.7 + 0.25 (5) 2.0 + 0.3
5.1 + 0.8 (5) 8.9 + 0.9
1.0 + 0.1 (8)
7.9 + 0.1+ (7) 8.2 + 0.8
1.61+ + o.l3 (6) 1.7 + 0.3
5.7 + 1.0 (5)
75 + 5a (2)
23.5 + 1.0 (6) 28 + 2
26.2 + 1.3M
™* _ i— D • Q
12.0 + 0.5U>
Livermore
Concn
(5 detns each)
2800 + 200
12.3 + 0.6
i
1.1+ + 0.1
1+.5 + 0.3
28 + 2
7200 + 700
2^£ + 2^4-
126 + 10
506 + 23
5.8 + 0.3
1+2 + 2
52 + 3
11.5 ± l.k
0.32 + 0.10
6-.1+ + 0.1+
2600 + 200
65 + 7
135~+ 7
11.1 + 0.7
2.2 + 0.2
5.8 + 0.9
3.5 + 1.1
23 + 1
Wash. State
Concn #
2970 + 50
1.73 + 0.08
26.2 + 1.7
7550 + 250
221+ + 12
122 + 7
1*80 + 12
6.2 + 0.5
1+2.8 + 2.1
105 ± 13
56 + 3
126 + 9
1500 + 200
6.3 + 0.1+
8.0 + 0.8
2700 + 50
82 + 2
2.7 ± 0.2
7.5 + 0.5
2.1 + 0.3
23.2 + 1.6
of detns
W
(k)
(20)
W
(5)
(20)
(5)
(19)
(1»+)
(10)
(1+)
(15)
(20)
(10)
(U)
(20)
(k)
(15)
(19)
(18)
(19)
OBML HBS
Concn Concn
3070
1.98
12.5
1.8
1+.31+
32
61+20
21*0 21U.8
138 131 + 2
1+60 1+93 + 7
637
1+6 38
109 98 + 3
208 210 + 2C
51+ 61 + 6
9.1+ + 0.5
120 112
7.8
2780
82
15
2.86
10.8
1.6
78 + 1+ 70 + 1+
26 2l+
11.8 11.6 + 0.2
Done by instrumental photon activation analysis _
Done by direct gamma-ray counting of natural radioactivity
Twelve determinations
One sample of 100 g counted five times
for 1,000 min.
each
103
-------
SECTION 8
MODIFIED ASH
The recent establishment of more stringent air pollution regulations for the
utility industry may result in significant changes in types of coal ash pro-
duced. Changes in present utility practice have been proposed, such as flue
gas desulfurization processes, coal gasification and liquefaction processes,
greater utilization of certain types of coal, and new power plant designs.
While coal fractionation processes would produce residues at the conversion
facility, the other three proposals would result in modified residues at the
generating plant itself.12
Effects of these three proposals have been studied in varying depth. Ashes
from different coal types have been summarized above. New power plant
designs for reduced environmental impact are largely in the conceptual stages
at present. However, several flue gas desulfurization processes have been
developed and tested in recent years. These may considerably alter the
nature of collected residue. Also, these scrubbing processes generally
produce a significantly increased quantity of utility waste residue.12
The chemistry of scrubbing power plant stack gases is complex and is still
under study. Hollinden1*1* explains that "The overall reaction is that of SO
with CaO or CaCO to form calcium sulfite, with some oxidation of the sul-
fite to sulfate. The actual reaction path to these end products, however,
appears to be complex, with gas-liquid reactions, both ionic and nonionic
reactions in the liquid phase and liquid-solid reactions all taking place."
The sludge resulting from the scrubbing of stack gases utilizing lime or
limestone has been characterized by Selmeczi and Knight.1*5 This sludge con-
tains the same basic elements as those found in bottom ash and flyash (see
Table 41). However, the levels of concentrations of most of these elements
are generally lower in scrubber sludge due to the dilution effect of the
scrubbing slurry and of the SO removed from the gas stream. The chemical
composition of the sludge solids is affected by the type of fuel, boiler
operating conditions, type of scrubber, liquid-to-gas ratio, pH, chemical
composition, and quantity of scrubbing solution used. The chemistry and the
quantity of the flyash constituent in the sludge depends on the type of coal
burned and the efficiency of any flyash removal system which may be located
upstream from the scrubber.'t5
X-ray diffraction studies conducted under the same program gave the follow-
ing results. "In the conventional lime scrubbing process sludges, the major
-------
TABLE iH. CHEMICAL COMPOSITION OF LIME PROCESS
SCRUBBER SLUDGE ON DRY SOLID BASIS
(percent)
Sample
Element
A
B
CaO
MgO
Total Sulphur
so2
so3
co2
Free Carbon
Ka20
KJD
31.6
18.3
U.3
18.1
2.U
7-2
12.1
2.9
3.2
ND
ND
ND
U.9
3A
.6
U3.2
.2
18.9
33.0
5.9
6.7
ND
ND
ND
.58
1.21
.39
U3A
.01
20.0
29.2
13.6
7.1
2.8
.35
.03
ND - Not determined
Sample A - Eastern Power Plant - 19* ash; 1-9^ sulfur sa^le taken upstream of
flyash collection device.
Sample B - Same as "A" except sludge from scrubber located downstream of
flyash collector.
C - Western Power Plant - Scrubber located downstream of ash collector,
105
-------
component beside flyash is calcium sulfite hemihydrate, CaSC>3 • 1/2 E^O.
Calcium carbonate was not definitely identified, partly because of the low
concentration and partly because it was a very poorly crystallized precipi-
tate. Gypsum again was typically missing from the patterns, but a sulfate-
containing phase, ettringite, 3CaO • Al-O.^ • SCaSO^ • X HO, was indicated in
the flyash-containing sludges. In the dry-limestone-injected wet scrubbed
sludge, gypsum was a major phase, in excess of 5 percent."1*5 Both CaCO
and CaSO • 1/2 H.O were identified as major phases in the limestone
process sludge.
The crystal morphology of these sludges was also determined by scanning
electron microphotographs. These photographs revealed the characteristics
of calcium sulfite crystal clusters. Individual crystals were very thin
platelets with 10 to 100 micron lateral dimensions and thickness of 0.1
to 0.5 micron. However, since calcium sulfite has a tendency to grow in
clusters, single crystals were rarely seen. Depending on the S02 content
of the gas, the density of a cluster varied considerably. A low-sulfur,
western-coal, scrubber sludge was found to have the loosest clusters with
increased amounts of gypsum crystals present. Gypsum crystals were not
usually observed in sludges produced by wet lime scrubbing of eastern high-
sulfur coals. Calcium carbonate was readily identifiable in block forms
in the wet limestone scrubbing sludge.1*5
Rossoff and Rossi1*6 and Leo and Rossoff1*7 of the Aerospace Corporation have
also reported on the chemical and physical characteristics of sludges.
Seven utility power plants (Table 42), covering a variety of scrubber types,
capacities, coal sources, and absorbents were included in the latter report.
In addition to sludge characterization, changes in the system chemistry
caused by variables such as time, traversal through the system, and pH and
ionic strength were also investigated. The following conclusions were
derived from their studies.1*7
1. Other than increased concentrations of potassium, which may be due
to leaching of flyash, the concentrations of major, minor, and
trace elements in scrubber liquors tend generally to decrease along
the path of the process.
2. Based on sampling at four of the plants over periods of 4 to 16
months, indications are that a rapid increase in the concentrations
of major species occurs and attains comparatively stable conditions
at a concentration where the rate at which a constituent is lost in
the waste product equals the rate at which that constituent is
scrubbed from the flue gas. Trace elements displayed initial
increases in concentration following startup. Thereafter, however,
except for lead, they did not show a trend in concentration level
with time.
3. It appears that trace element concentration of scrubber liquors in
a system is not controlled by ionic strength of the liquor or by
system pH.
4. In comparing trace metal concentrations in scrubber liquor from the
lime, limestone, and double alkali processes, these concentrations
(As, Be, Cd, Cr, Cu, Hg, Pb, Se, and Zn) were generally highest in
106
-------
TABLE 1+2. PGD SYSTEMS SAMPLED AS DATA BASE (1*7)
Power Plant
TVA Shawnee
Steam Plant
TVA Shawnee
Steam Plant
Arizona Public
Service Company,
Cholla Power
Plant
Duquesne Light
Company,
Phillips Power
Station
General Motors
Corporation,
Chevrolet- Parma
Power Plant
Southern California
Edison, Mohave
Generating Station
Utah Power and
Light Company,
Gadsby Station
Scrubber
System
Venturi and
spray tower,
prototype
Turbulent
contact
absorber.
prototype
Flooded-disk
scrubber,
•Betted film
absorber
Single- and
dual-stage
venturi
Bubble-cap
tower
Turbulent
contact
absorber.
pilot plant
Venturi, and
mobile bed.
pilot plant
Scrubbing
Capacity,
MW (equiv)
10
10
120
410
32
< 1
< 1
Coal
Source
Eastern
Eastern
Western
Eastern
Eastern
Western
Western
Absorbent
Lime
Limestone
Limestone,
fly ash
Lime
Soda ash.
lime
Limestone
Soda ash.
lime
107
-------
the limestone system and lowest in the double-alkali system with
trace metal concentrations in the lime system falling between the
two.
Leo and Rossoff further concluded from their studies that trace element
concentrations in the scrubber waste solids and liquors seemed to depend on
the trace element concentrations of input materials, especially coal.
Variations in the data may be caused by varying quantities of fly ash in
the scrubber wastes, as well as the scrubbing efficiency relative to each
element. Results of this study indicate that the main source of trace
metals in the waste is the fly ash in the waste. Wastes with higher flyash
content tend to have higher trace element concentrations. Mercury and
selenium are two exceptions. Although they are found at relatively low
concentrations in the flyash, existing primarily in the flue gas stream as
vapors or very fine particulates, their relative concentrations in scrubber
waste are comparable to the other trace elements. This indicates that these
elements are at least partially removed from the flue gas.
Table 43 shows the phase composition of the major solid constituents of the
sludges in the Aerospace study.47 The four main crystalline phases contained
in these sludges were flyash, calcium sulfite, calcium sulfate, and unreacted
limestone or precipitated calcium carbonate. The quantities of these crys-
talline phases relative to each other depend on factors such as sulfur con-
tent of the coal, efficiency of scrubbing S0_, flyash removal efficiency of
the system, stoichiometric ratio of reactants relative to fuel sulfur con-
tent, reactant utilization efficiency, and the degree of oxidation of sulfur
products in the system.
Scrubber wastes contain fine particulates suspended in an aqueous medium.
Particle size for both sulfate and sulfite particles ranges between 1 urn and
100 ym, a range comparable to that of flyash particles. However, particle
shapes differ; flyash particles are generally spherical, while sulfate parti-
cles are block-like and sulfites are plate-like. The thixotropic nature of
flue gas desulfurization waste is usually attributed to the plate-like shape
of the sulfites.47
Viscosity measurements on the seven sludges tested showed that the pumpable
mixtures (<20 poise) had solids contents ranging from 32 to 70 percent.
Results of the tests suggested that flyash tends to reduce the viscosity of
these wastes.47
Tables 44 shows the wet bulk densities of eight sludges, each of which was
dewatered in the laboratory by four techniques. Results indicate that for
most of these sludges, highest density was noted from dewatering by vacuum-
assisted filtration. For the other sludges, centrifugation gave highest
density. Sludges with the coarsest particle size distributions showed the
best overall dewatering characteristics.1*7
Table 45 gives permeability coefficients for untreated and chemically fixed
sludges. For untreated wastes, these generally range from 2 x 10"^ to 1 x
10~5 cm/sec. Chemical treatments tended to result in decreased permeability,
108
-------
TABLE i|3. PHASE COMPOSITION OF FGD WASTE SOLIDS IN WEIGHT PERCENT8-
Atomic
Formula
CaSO4'2H2O
CaSO,- t/2H2O
CaSO4- 1/2H2O
CaCOj
MgSO4'6H2O
CaS2O3-6H2Oa
Na2S04'7H20
NaCl
CaS04a
CaS30)0a
Fly Ash
Total
TVA Shawnee
Lime stone,
2/1/73
21.9
18.5
38.7
4.6
20. 1
103.8
TVA Shawnee
Limestone,
7/12/73
15.4
21.4
20.2
3.7
40.9
101.6
TVA Shawnee
Limestone,
6/15/74
31.2
21.8
4.5
1.9
40. 1
99. 5
TVA Shawnee
Lime,
3/19/74
6.3
48.8
2.5
1.9
40. 5
100.0
SCE Mohave
Limestone,
3/30/73
84.6
8.0
6.3
1.5
3.0
103.4
CM Parma
Double Alkali,
7/17/74
48.3
12.9
19.2
7.7
6.9
7.4
101.4
APS Cholla
Limestone,
4/1/74
17.3
10.8
2. 5
14.3
58.7
103.6
DLC Phillips
Lime,
6/17/74
19.0
12.9
0.2
9.8
59.7
101. 3
UPL Gads by
Double Alkali,
8/9/74
63.8
0.2
10.8
17.7
8.6
101.1
o
VD
^Phases not explicitly measured; presence deduced from x-ray study.
-------
TABLE 44. DEWATERED BULK DENSITIES OF FGD WASTES (47)
Sample
Source
and
Date
Shawnee
Limestone,
2/1/73
Shawnee
Limestone,
6/15/74
Shawnee
Lime,
3/19/74
CM
Double Alkali,
7/18/74
Utah
Double Alkali,
8/9/74
Duquesne
Lime,
6/17/74
Cholla
Limestone,
9/1/74
Mohave
Limestone,
3/30/73
Dewatering Method
Settled
Percent
Solid s
49.0
52.9
41.5
40.0
37.2
47.6
46.7
66.6
Density,
g/cc
1.45
1.46
1.34
1.31
1.30
1.40
1.39
1,65
Settled and
Drained
Percent
Solids
55.7
58.3
43.4
43.9
41.4
53.1
50.9
67.2
Density,
g/cc
1.51
1.53
1.36
1.35
1.33
1.48
1.44
1.67
Centrifuge
Percent
Solids
59.8
63.3
49.9
50.9
62.2
57.2
60.9
77.0
Density,
g/cc
1.56
1.60
1.44
1.43
1.62
1.52
1.58
1.86
Filter
Percent
Solids
65.0
65.9
56.0
57.8
54.6
57,0
53.4
80.3
Density,
g/cc
1.65
1.64
1.51
1.52
1.50
1.52
1.48
1.78
110
-------
TABLE 45.
PERMEABILITY OF UNTREATED AND CHEMICALLY FIXED FGC WASTES (47)
Sample
Source
Shawnee
Lime stone
Shawnee
Lime
Mohave
Dusque sne
GM
Double Alkali
Cholla
Utah
Double Alkali
Shawne e
Limestone
(IUCS)
Shawnee
Limestone
(IUCS)
Mohave
(IUCS)
Shawnee
Lime
(IUCS)
Shawnee
Limestone
(Chemfix)
Shawne e
(Dravo)
Duquesne
(Calcilox)
Sample
Date
2/1/73
6/15/74
6/15/74
6/15/74
6/15/74
3/19/74
3/19/74
3/19/74
3/30/73
3/30/73
3/30/73
6/17/74
6/17/74
6/17/74
7/18/74
7/18/74
7/18/74
4/1/74
4/1/74
4/1/74
8/9/74
8/9/74
8/9/74
5/29/75
6/12/75
2/27/75
6/12/75
Replications*
1
3
1
3
3
1
1
(2)
(3)
3
3
(2)
3
2
(2)
1
1
(2)
1
1
1
1
(2)
(2)
(5)
(2)
1
1
1
1
(2)
1
1
1
1
(2)
1
1
"
Fractional
Void
Volume
0.69
0.60
0.58
0. 58
0.55
0.75
0.74
0.72
0.47
0.43
0.34
0.68
0.58
0.49
0.71
0.69
0.65
0.56
0.54
0.54
0.75
0.73
0.70
0.69
0.54
0.55
0.65
0.53
0.57
0.68
0.72
0.70
0.78
0.75
0.70
0.78
0.76
Permeability
Coefficient,
cm/sec
2.3 X10-*
l o v in
* • v X ^U r
Q A Y f A"3
7 » "J X * v r
a c v.in
o « j X * U e
5.9 x 10"b
1 7 x 10"*
* • • J\ >. \f —
5.3 x 10"=
6.0 x 10~S
5.0 x 10"*
7.5 x 10
-f s* * v .
1.6 x 10"4
1.2 x 15"*
1.3 x 10":
7.4 x 10
8.2 x 10"?
2.5x 10 "!
8.1 x 10"s
2.7 x 10"*
1.8x 10";
1.1 x 10~a
9.8 x 10"*
1.3x 1C"'
1.2X 10"*
2.2 x 10"*
5.5x 10"8
7.9 X 10"*
7.3x 10'*
1.9 X 10
5.5X tO"*
5.5 x 10"'
4.1 x 10"5 ,
1.5-2.) x 10"5
4.7 x lO'5
3.2 x 10"*
6.9 x I0"b
3.8x10"*
4.9x 10 4
2.1 x 10
Remarks
Column packed as slurry
Compacted wet
Compacted wet
Column packed -as slurry
Compacted wet
Compacted wet
Compacted wet
Pulverized
S.olid, undisturbed
Pulverized
Pulverized
Pulverized, compacted wet
Solid, undisturbed
Solid, undisturbed
Pulverized
Solid, undisturbed
Pulverized
Pulverized
Solid, undisturbed
Pulverized
Pulverized
Pulverized, compacted wet
Replications of those in parenthesis refer to multiple measurements on a single column using varying
hydraulic heads.
Ill
-------
while fracturing the treated wastes increased permeability. Weathering
(exposure to the cycle of freezing and thawing) tended to cause cracks in
treated wastes in the field and, therefore, to increase permeability.47
Compaction of the sludges under load ranged from 5 to 15 percent. Permanent
compaction after load release, however, was only 1 to 3 percent.47 It
appears that effective packing occurs only when the sludge involved contains
predominantly block-like (gypsum crystals) rather than plate-like particles
(sulfite crystals), although it has been seen that the size of the plates
can have a dramatic effect on compaction. Large sulfite platelets have
been found to settle and compact almost as well as gypsum.48
Sludges with solids content of 55 to 70 percent were measured for load
bearing strength. A strength of 2.1 to 2.4 x 106 dyne/cm2 was noted for a
Shawnee sludge having 70 percent solids. At 55 percent solids, sludges
showed virtually no ability to bear load.47
Combustion Engineering conducted a study in sludge characterization using a
group of 10 samples selected to represent the material that would be produced
by various kinds of air pollution control systems using lime or limestone
scrubbing (Table 46). The chemical composition of these samples is shown in
Table 47.49»50
The Dravo Corporation also investigated sludges from various scrubbing
systems.50 The sludges studied were the following.
A. Sludge A was from a power station burning coal with 19 percent ash
and 1.9 percent sulfur and using a two-stage venturi lime scrubber.
The flue gas for the scrubber was taken upstream from the flyash
collecting devices.
B. Sludge B was from the same station, but the gas was scrubbed down-
stream of the flyash precipitator. This sludge has a lower flyash
content.
C. Sludge C was taken from the Chemico installation at the Mitsui
Aluminum Company in Ohmuta City, Japan. They were burning a 9,000-
Btu brown coal with 30 percent ash and 1.9 percent sulfur and
scrubbing with a byproduct of carbide lime. The flyash content of
the sludge was estimated to be 5 percent.
D. Sludge D was from a western power plant using a proprietary scrub-
bing device. Scrubbing occurred downstream from the flyash preci-
pitator and the SO content of the gases was approximately 380 ppm.
E. Sludge E was from a pilot plant based on the dry injection of lime-
stone followed by wet scrubbing (marble bed).
F. Sludge F was obtained from a pilot plant scrubber on a molybdenum
sulfide roaster using a four-tray TCA scrubber. The flue gas
normally contains 1.2 percent SO and .05 percent SO . At 90
percent efficiency, the scrubber could operate at 100 percent lime
s toichiometry.
G. Sludge G was produced by a double alkali system on the General
Motors pilot plant burning high-sulfur oil with 100 percent excess
air. The sludge solids consisted essentially of calcium sulfate
with a minor amount of calcium carbonate and free carbon.
112
-------
TABLE U6. IDENTIFICATION OF APCS SLUDGE STANDARDS (50)
STD I - Fly ash from Connecticut Light and Power Company's Devon Station.
STD II - CE sludge - CaiCO^, 150-percent stoichiometry, 2000-ppm S02.
STD III - Kansas Power and Light sludge.
rVTD IV - CE sludge - Ca(OH)2, 38- to 50-percent stoichiometry, 50- to 60-
percent S02 removal, slurry feed 220 gpm, recycle 165 gpm with
55-gpm blowdown.
STD V - Union Electric sludge.
STD VI - CE sludge - CaCOg, 150-percent stoichiometry, ^5- to 55-percent
removal, no recycle.
STD VI A - STD VI plus 50-percent STD I (fly ash).
STD VII - CE sludge - 300- to 325-percent stoichiometry, 6lj~percent S02 removal,
300 lb/hr fly ash, 550 lb/hr CaC03.
STD VIII - CE sludge - 120- to 130-percent stoichiometry Ca(OH)2, no fly ash
addition.
STD IX - CE sludge - 220-gpm H20 spray, 275 Ib/far lime feed» 300°F reaction
temperature »,
113
-------
TABLE 1*7. WET CHEMICAL ANALYSIS OF SLUDGE STANDARDS (1*7)
(percent)
STD I STD II STD III STD IV STD V STD VI STD VIA STD VII STP VIII STD IX
Si02
Al20o
Fe203
CaO
MgO
Na20
KgO
Ti02
P2°5
C02
so2
S03
CaCO.-,
U6.7
23.2
13.7
1*.7
0.9
0.3
2.6
1.5
0.3
2.6
—
0.8
5.9
1.5
0.32
0.27
1*9.6
0.51*
O.Ol*
0.17
<0.02
0.05
29.2
11.7
3.5
65.7
30.7
6.6
8.6
22.7
1.5
0.50
l.l
0.26
0.11
5.3
5.8
6.5
12.0
0.79
0.05
0.18
1*2.5
0.10
0.03
0.05
<0.02
0.06
3.7
38.8
3.3
8.1*
19. ^
6.8
5.4
27.6
3.2
0.08
0.2l*
0.32
0.08
7.2
2.2
12.3
16.3
1.1
0.01
0.09
52.5
0.52
0.02
O.ll*
<0.02
0.13
36.6
6.3
0.5
80.6
27
ll*
8
21*
0
0
1
0
0
15
3
<0
3*
.7
.7
.3
.2
.70
.16
.2
.79
• 19
.3
.1*
.1
.7
1*.6
2.3
1.6
1*0.1
0.20
0.05
0.29
0.11
0.08
13.6
5.U
2l*.9
30.9
1.2
0.1*8
0.72
1*2.5
0.90
0.05
0.07
<0.02
0.06
11.5
2l*.l
8.1*
26.1
2.0
0.1*5
0.72
1*6.2
0.1*0
O.Ol*
0.21
0.02
0.07
21*. 1*
13.7
l*.l*
55.U
-------
Table 48 presents the results of chemical analyses for these sludges. X-ray
diffraction studies on vacuum-dried sludge samples revealed that calcium
sulfite hemihydrate was in the tailend lime scrubbing process. This compound
was the main constituent of the sludge material other than flyash. A sulfate
containing phase, ettringite, 3CaO • Al 0 • 3CaSO • XH 0, was found in the
sludges containing flyash. Sludges produced by the limestone injection wet
scrubbing process contained gypsum as a major phase (excess of 5
percent).
115
-------
IA.BLE 14-8. CHEMICAL ANALYSIS OF LIME PROCESS SLUDGES IN PEECENT ON DEI SOLID BASIS (50)
CaO
MgO
Total S
so2
SO
co2
Free C
SiO
A12°3
Fe2°3
Na20
K20
Free Base
(as CaO)
A
18.1
2.1*
7.2
12.1
2.9
3.2
-
31.6
18.3
M
-
-
0.3
B
43.2
0.2
18.9
33.0
5.9
6.7
-
ii Q
Q h
0.6
-
-
1.3
C
1*0.7
-
18.1
32.9
i*.8
2.3
-
3.76
1.71
0.86
-
-
7.9
D
1*3 A
0.01
20.0
29.2
13.6
7.1
2.8
0.58
1.21
0.39
0.35
0.03
0.06
E
25.6
1.2
10.9
10.8
13.6
2.2
O.ll*
21.3
11.3
5.6
0.76
0.98
0.06
F
1*3.8
-
22.9
1*5.8
0
1.0
0
0.18
0.39
0.29
0.09
0.01
0
G
25.6
1.2
8A
11.6
6.1*
30.0
1.8
l.l*
0.59
0.27
0.52
0.14
0
-------
REFERENCES
1. Bertine, K. K., and E. D. Goldberg. Fossil Fuel Combustion and the Major
Sedimentary Cycle. Science. Vol. 173: 233-235, July 1971.
2. iCLein, David H., Anders W. Andren, Joel A. Carter, Jeul F. Emery, Cyrus
^ /Feldman, William Fulkerson, William S. Lyon, Jack C. Ogle, Yair Talmi,
v Robert I. Van Hook, and Newell Bolton. Pathways of Thirty-Seven Trace
Elements Through a Coal-Fired Power Plant. Oak Ridge National Laboratory,
Oak Ridge, Tennessee, 1975. 2k p.
3. Lee, Robert E., Jr., Howard L. Crist, Allan E. Riley, and Kathryn E.
Macleod. Concentration and Size of Trace Metal Emissions From a Power
Plant, a Steel Plant, and a Cotton Gin. Environmental Science and Tech-
nology. Vol. 9 (No. 7): 643-647, July 1975.
k. Davison, Richard L., David F. S. Natusch, John R. Wallace, and Charles A.
Evans, Jr. Trace Elements in Fly Ash - Dependence of Concentration on
Particle Size. Environmental Science and Technology. Vol. 8 (No. 13):
1107-1113, December 1974.
Oglesby, S., Jr. A Survey of Technical Information Related to Fine-
Particle Control. Southern Research Institute, Birmingham, Alabama.
Publication Number EPRI 259- Electric Power Research Institute. April
1975. 246 p.
6. KaaKinen, John W., Roger M. Jorden, Mohammed H. Lawasani, and Ronald E.
West. Trace Element Behavior in Coal-Fired Power Plant. Environmental
Science and Technology. Vol. 9 (No. 9): 862-869, September 1975.
7. Magee, R. A., F. B. Meserola, and R. G. Oldham. Coal Fired Power Plant
Trace Element Study. Vol. I: A Three Station Comparison. Radian Corpor-
ation. Austin, Texas. Environmental Protection Agency. September 1975-
50 p.
8. Coal Fired Power Plant Trace Element Study. Vol. II: Station I. Radian
Corporation, Austin, Texas. 51 P.
9. Coal Fired Power Plant Trace Element Study. Vol. Ill: Station II. Radian
Corporation, Austin, Texas. 44 p.
10. Coal Fired Power Plant Trace Element Study Vol. IV: Station III. Radian
Corporation, Austin, Texas. 47 p.
H. Ondov, J. M., W. H. Zoller, I. Olmez, N. K. Aras, and G. E. Gordon. Ele-
mental Concentration in the National Bureau of Standards Environmental Coal
and Fly Ash Standard Reference Materials. Analytical Chemicstry. vol. m
(No. 7): 1102-1109, June 1975.
117
-------
12. Hecht, N. L. and D. S. Duvale. Characterization and Utilization of
Municipal and Utility Sludges and Ashes. Vol. II: Utility Coal
Ash. University of Dayton, Dayton, Ohio. Publication Number PB-21+1+312.
Environmental Protection Agency. May 1975. 66 p.
13. Averitt, P. Coal Resources of the United States, January 1, 197^- U.S.
Geological Survey. U.S.G.S. Bulletin 11+12. U.S. Department of Interior.
1J+. Surprenant, N., R. Hall, S. Slater, T. Suza, M. Sussman, and C. Young.
Preliminary Environmental Assessment of Conventional Combustion Systems.
Vol. I. GCA Corporation, Bedford, Massachusetts. Publication Number
GCA-TR-75-26-G. Environmental Protection Agency. August 1975. 26*1- p.
15. Given, P. H. Problems in the Chemistry and Structure of Coals as Re-
lated to Pollutants from Conversion Processes. Pennsylvania State Uni-
versity. Publication Number EPA -6 50/2-7^-118. Environmental Protection
Agency. October 197*+. 27-3*+.
16. Magee, E. M., H. J. Hall, and G. M. Varga, Jr. Potential Pollutants
in Fossil Fuels. Esso Research and Engineering Company, Linden, New
Jersey. Publication Number PB-225039. Environmental Protection Agency.
June 1973. 151 P.
17. Billings, Charles E., Anthony M. Sacco, Wayne R. Matson, Reginald M.
Griffin, William R. Conigilo, and Robert A. Harley. Mercury Balance on a
Large Pulverized Coal-Fired Furnace. Journal of the Air Pollution
Control Association. Vol. 23 (No. 9): 773-777, September 1973.
18. Mineral Matter and Trace Elements in U.S. Coal. Office of Coal Research.
Publication Number Research and Development Report No. 6l. Pittsburgh,
Pa., 1972.
19. Abernethy, R. F., and F. H. Gibson. Rare Elements in Coal. Bureau of
Mines. Publication Number 1C 8163. Department of Interior.
20. Preliminary Report of Coal Drill -Hole Data and Chemical Analyses of
Coal Beds in Sheridan and Campbell Counties, Wyoming and Big Horn County,
Montana. U.S. Geological Survey Open-File Report. U.S. Geological
Survey and the Montana Bureau of Mines and Geology. 1973. 57 p.
21. Steam-Electric Plant Air and Water Quality Control Data. Federal Power
Commission. Publication Number FPC-S-229. Washington, DC, February
1973.
22. Plumley, A. L. Fossil Fuel and the Environmental- Present Systems and
their Emissions. Combustion: 36-1+3, October 1971.
23. Chu, T. I. J., P. A. Krenkel, and R. J. Ruane. Reuse of Ash Sluicing
Water in Coal-Fired Power Plants. Tennessee Valley Authority, Chattanooga,
Tennessee. Prepared for the Third National Conference on Complete Water
Reuse, Cincinnati, Ohio, June 27-30, 1976. 29 p.
118
-------
2U. Combustion. In: Chemical Engineers Handbook, Perry, J H et al eds
New York, MaGraw-Hill, 1950. '
25. Moulton, L. K. ^Bottom Ash and Boiler Slag. West Virginia University.
Presented at Third International Ash Utilization n ^. , , ,
26. Mather, B. Nature and Distribution of Particles of Various Sizes in
Fly Ash. Corps of Engineers, Vicksburg, Mississippi. Technical Report
No. 6-583. 19ol.
27. O'Gorman, J. V., and P. L. Walker, Jr. Mineral Matter and Trace Elements
in U.S. Coals. Pennsylvania State University. University Park. Research
and Development Report, No. 6l. Department of Interior. July 1972
81-101 p.
28. Bolton, N. E., R. I. Van Hook, W. Fulkerson, W. S. Lyon, A. W. Andren,
J. A. Carter, and J. F. Emery. Trace Element Measurements at the
Coal-Fired Allen Steam Plant. Oak Ridge National Laboratory, Progress
Report June 1971-January 1973. National Science Foundation. Publication
Number EP-^3. March 1973. 83 p.
29. Cowherd, Chatten, Jr., Mark Marcus, Christine M. Guenther, and James L.
Spigarelli. Hazardous Emission Characterization of Utility Boilers.
Midwest Research Institute. Environmental Protection Agency. Publica-
tion Number EPA-650/2-75-066. July 1975. 175 p.
30. Swanson, V. E. Coal Resources Work Group, Southwest Energy Study.
Appendix J.-Part II. January 1972.
31. Gordon, G. E., D. D. Davis, G. W. Israel, H. E. Landsberg, T. C. O'Haver,
S. W. Staley, and W. H. Zoller. Study of the Emissions from Major Air
Pollution Sources and their Atmospheric Interactions. University of
Maryland, College Park, Maryland. Prepared for the National Science
Foundation for the period November 1, 1972 - October 31, 197^-
32. Kaakinen, John W., and Roger M. Jorden. Determination of a Trace Element
Mass Balance for a Coal-Fired Power Plant. Presented at First Annual
National Science Foundation Conference on Trace Contaminants, Oak Ridge,
Tennessee. August 1973- 20 p.
33. Brown, J., and A. Guest. Continuing Analysis of Trace Elements in Coal.
The Hydro-Electric Power Commission of Ontario Research Division, Toronto,
Ontario, Canada, June 1973. 17 P.
3^. Trace Element Measurements at the Coal-Fired Steam Plant. Oak Ridge
National Laboratory, Progress Report February 1973 - July 1973.
National Science Foundation. Publication Number EP - 62. June 197^. ^3 P-
119
-------
35. Lyon, W. S. Trace Element Profiles Through a Coal-Fired Steam Plant -
A Quarterly Progress Report for Period April - June, 1972. Oak Ridge
National Laboratory, Oak Ridge, Tennessee, July 1972. 13 P.
36. Lee, Robert E., Jr., and Von Lehmden. Trace Metal Pollution in the
Environment. Journal of the Air Pollution Control Association. Vol. 23
(No. 10): 853-857, October 1973-
37. Schlesinger, M. D., and Hyman Schultz. Analysis for Mercury in Coal.
Bureau of Mines, Technical Progress Report 1+3. September 1971. 5 p.
38. Ad Hoc Panel on Abatement of Particulate Emission from Stationary Sources.
Publication No. COPAC-5- National Research Council, Washington,'DC. 1972.
37 P.
39• Von Lehmden, Darryl J., Robert H. Jungers, and Robert E. Lee, Jr.
Determination of Trace Elements in Coal, Fly Ash, Fuel Oil, and Gasoline -
A Preliminary Comparison of Selected Analytical Techniques. Analytical
Chemistry, Vol. k6 (No. 2): 239-21+5, February 197^.
40. Gordon, G. E., D. D. Davis, G. W. Israel, H. E. Landsberg, T. C. O'Haver,
S. W. Staley, and W. H. Zaller. Study of the Emissions from Major Air
Pollution Sources and their Atmospheric Interactions. University of
Maryland. Prepared for the National Science Foundation for the period
November 1, 1972 - October 31, 1974.
1+1. Brown, R., M. L. Jacobs, and H. E. Taylor. A Survey of the Most Recent
Applications of Spark Source Mass Spectrometry. American Laboratory.
29-1+0, November 1972.
1+2. Birks, L. S., J. V. Gilfrich, and P. G. Burkhalter. Development of X-Ray
Fluorescence Spectroscopy for Elemental Analysis of Particulate Matter in
the Atmosphere and in Source Emissions. EPA-R2-72-063, Environmental
Protection Agency, Cincinnati, Ohio, October 1972. 1+3 p.
k3- Birks, L. S., J. V. Gilfrich, and D. J. Nagel. Large Scale Monitoring of
Automobile Exhaust Particulate. Naval Research Laboratory Memo Report
2350. October 1971.
1+1+. Hollinden, G. A. Chemistry of Lime/Limestone Scrubbing Liquor from
Power Plant Stack Gases. Presented at 35th Annual Meeting International
Water Conference, Pittsburgh, Pennsylvania, October 30-November 1, 197!+.
20 p.
1+5. Selmeczi, J. G., and R. G. Knight. Properties of Power Plant Waste Sludge.
Presented at Third International Ash Utilization Symposium, Pittsburgh,
Pa., March 13-11+, 1973.
1+6. Rossoff, J., and R. C. Rossi. Disposal of By-Products from Non-Regenerable
Flue Gas Desulfurization Systems: Initial Report. EPA-650/2-7!+-037-2,
U.S. Environmental Protection Agency, Washington, D.C., 197!+.
120
-------
1)7. Leo, P. P., and J. Rossoff. Control of Waste and Water Pollution from
Power Plant Flue Gas Cleaning Systems: First Annual Research and
Development Report. EPA-600/7-76-018, U.S. Environmental Protection
Agency, Washington, B.C., 1976. 167 p.
Ii8. Crowe, J. L. Processing Sludge: Sludge Characterization Studies,
Quarterly Progress Report Wo. 3 (October 1 to December 1, 1975). Prepared
by the Tennessee Valley Authority for the U.S. Environmental Protection
Agency, Research Triangle Park, Worth Carolina, January 1976.
1+9. Taylor, ¥. C. Experience in the Disposal and Utilization of Sludge from
Lime/Limestone Scrubbing Processes. Presented at the Flue Gas Desulfur-
ization Symposium, New Orleans, Louisiana, May 1^-17, 1973-
50. Crowe, J. L. Study of Sludge Disposal from Sulfur Dioxide and Particu-
late Removal Processes: Subtask I Report. Tennessee Valley Authority,
Chattanooga, Tennessee, 197U. 62 p.
121
-------
BIBLIOGRAPHY
1. Abernathy, R. F., M. J. Peterson, and F. H. Gibson. Major Ash Consti-
tuents in U.S. Coals. Bureau of Mines Report No. 72^0.
2. Andren, A. W., and D. H. Klein. Selenium in Coal-Fired Steam Plant
Emissions. Environmental Science and Technology. Vol. 9 (No. 9):
856-858, September 1975.
3. Attari, A. Fate of Trace Constituents of Coal During Gasification.
Institute of Gas Technology. Chicago, Illinois. Publication Number
EPA -6 50/2 -73 -00k. Environmental Protection Agency. August 1973. 31 P.
U. Bailey, M. E. The Chemistry of Coal and its Constituents. Journal of
Chemical Education. Vol. 51 (No. 7): M4-6-W3, July 197^.
5. Banker t, S. F., S. D. Bloom, and G. D. Sauter. Trace Element Analysis
in Water by Proton Activation. Analytical Chemistry. Vol. 4 5 (No. h):
692-697, 1973.
6. Billings, Charles E., and Wayne R. Matson. Mercury Emissions from Coal
Combustion. Science. Vol. 176: 1232-1233, June 1972.
7. Bird, Alvin N., Jr., Joseph D. McCain, and Bruce D. Harris. Particulate
Sizing Techniques for Control Device Evaluation. Southern Research
Institute, Birmingham, Alabama. Report Number 73-282. March 1973. 22 p.
8. Breslin, Alfred J., Frederic S. Guggenheim, and A. C. George. Compact
High-Efficiency Diffusion Batteries. Staub-Reinhalt Luft. Vol. 31
(No. 8): 1-5, August 1971.
9. Brink, J. A., Jr. Cascade Impactor for Adiabatic Measurements.
Industrial and Engineering Chemistry. Vol. 50 (No. k): 6^5-6^8, April 1958.
10. Camp, D. C., J. A. Cooper, and J. R. Rhodes. X-Ray Fluorescence
Analysis - Results of a First Round Intercomparison Study. X-Ray
Spectrometry (London). Vol. 3: ^7-50,
11. Capp, J. P., and J. D. Spencer. Fly Ash Utilization. Bureau of Mines.
Publication Number 1C 8^83. Department of Interior.
12. Chattapadhy, A., L.G.I. Bennett, and R. E. Jervis. Activation
Analysis of Environmental Pollutants. Canadian Journal of Chemical
Engineering. Vol. 50: 189-193, April 1972.
122
-------
13. Cooper Douglas W and John w. Davis. Cascade Impactors for Aerosols:
Februlr? i^AnalySiS- African Industrial Hygiene Association Journal.
1A. Cooper, J. A. Comparison of Particle and Photon Excited X-Ray Fluorescence
Applied to Trace Element Measurements of Environmental Samples. Nuclear
Instruments and Methods. Vol. 106: 525-538, 1973.
15. Cooper, J. A. Review of a Workshop on X-Ray Fluorescence Analysis
of Aerosols. National Science Foundation. Publication Numbers
NSF/RAM/IT/GI-38226/TR-73-5. Battelle Pacific Northwest Laboratory,
June 1973- 10 p.
16. Coutant, R. W., J. S. McNutty, and R. D. Giammar. Determination of
Trace Elements in a Combustion System. Battelle Columbus Laboratories,
Columbus, Ohio. Publication Number EPRI 122-1. Electric Power Research
Institute. January 1975. 35 p.
17. Crandall, Willard A. Determining Concentration and Nature of Particulate
Matter in Stack Gases. The American Society of Engineers. Publication
Number 71-WA/PTC-8. 1971. 16 p.
18. Crandall, Willard A. Determining Particulates in Stack Gases. Mechan-
ical Engineering. Vol. 12: 1^-22, December 1972.
19. Ctvrtnicek, T. E., S. J. Rusek, and C. W. Sandy. Evaluation of Low-
Sulfur Western Coal Characteristics, Utilization, and Combustion Experi-
ence. Monsanto Research Corporation, Dayton, Ohio. Publication Number
EPA-650/2-75-OU6. Environmental Protection Agency. May 1975. 555 P.
20. Curry, M. G., and G. M. Gigliotti. Cycling and Control of Metals.
National Environmental Research Center. Cincinnati, Ohio. Environmental
Publication Agency. Publication Number PB-2l6l8i|. February 1973- 187 p.
21. Dams, R., J. A. Robbins, K. A. Rahn, and J. W. Winchester. Nondestructive
Neutron Activation Analysis of Air Pollution Particulates. Analytical
Chemistry. Vol. k2 (No. 8): 861-867, July 1970.
22. Diehl, R. C., E. A. Hattman, H. Schultz, and R. J. Haren. Fate of Trace
Mercury in the Combustion of Coal. Pittsburgh Energy Research Center,
Pittsburgh, Pa. Publications Number TPR5^. Bureau of Mines. May 1972.
8 p.
23. Deul, M. and C. S. Annell. Elements in Ash of Low-Rank Coal from Texas,
Colorado, North Dakota and South Dakota. Department of Interior.
Geological Survey Bulletin 1036-H. 155-171.
2U. Falkenberry, H. L. Proposed ERC Investigations of Environmental Effects
of Current Ash and Sludge Disposal Practices. Tennessee Valley Authority,
Chattanooga, Tennessee, February 1973-
123
-------
25. Fiarman, S. Schneierg. Proton Activation Analysis for Trace Elements.
Environmental Science and Technology. Vol. 6: 79-81, January 1972.
26. Final Environmental Statement on Proposal Plan of Mining and Reclamation,
Big Shy Mine, Colstrip, Montana; Peabody Coal Company Coal Lease M-15965
March, 197^. U.S. Department of the Interior, U.S. Geology Survey,
Vol. I: 69-78.
27. Friedlander, S. K. Chemical Element Balances and Identification of
Air Pollution Sources. Environmental Science and Technology. Vol. 7
(Wo. 3): 235-2^0, March 1973.
28. Fuchs, N. A., I. B. Steehkina, and V. I. Starosselski. On the Deter-
mination of Particle Size Distribution in Polydisperse Aerosols by
the Diffusion Method. Brit. J. Appl. Phys. (London). Vol. 13: 280-281,
1962.
29. Fuel Ash Related to Boiler Design and Operation. In: Steam, Its
Generation and Use. The Babcock and Wilcox Company, New York, N.Y.,
1955-
30. Fulkerson, W. S. Toxic Elements and the Coal -Burning Power Station -
A Case Study. Oak Ridge National Laboratory, Oak Ridge, Tennessee,
October 1973. 3 p.
31. Gladney, E. S., W. H. Zaller, A. G. Jones, and G. E. Gordon. Composition
and Size Distribution of Atmospheric Particles Matter in the Boston Area.
Environmental Science and Technology. Vol. 8 (No. 6): 551-557, June
197^-
32. Gluskoter, H. J., and P. C. Lindahl. Cadmium: Mode of Occurrence in
Illinois Coals. Science. Vol. l8l: 26U-266, July 1973.
33. Gohshi, Y., T. Nakamura, and M. Yoshimura. Chemical State Analysis of
Vanadium by High Resolution X-Ray Spectroscopy. X-Ray Spec trome try
(London) Vol. k: 117-118,
3^. Goldfield, Joseph. Methods for Removing Contaminants. Plant
Engineering. February 197^-.
35. Goodman, R. J. Rapid Analysis of Trace Amounts of Tin in Stream
Sediments, Soils, and Rocks by X-Ray Fluorescence Analysis. Economic
Geology. Vol. 68 (No. 2): 275-278, April 1973.
36. Gorman, P., J. Nebgen, I. Smith, E. Trompeter, and J. Galeski.
Evaluation of the Magnitude of Potentially Hazardous Pollutant
Emissions from Coal and Oil-Fired Utility Boilers. Midwest Research
Institute, Kansas City, Missouri. Environmental Protection Agency.
August 1975. 130 p.
37. Gormley, P. G. , and M. Kennedy. Diffusion from a Stream Flowing Through
a Cylindrical Tube. Proceedings of the Royal Irish Academy. Vol. 52A:
163-169, May 19^9.
124
-------
38-
39. Growler, W. S. Hie Application of Modern Solvent Extraction Techniques
to the Removal of Trace Quantities of Toxic Substances from Industrial
Effluents. Oak Ridge National Laboratory. Oak Ridge, Tennessee.
Publication Number ORNL-TM-1+209. July 1973. 17 p.
UO. Guillaumin, J. C. Determination of Trace Metals in Power Plant Effluents
Atomic Absorption Newsletter. Vol. 13 (NO. 6): 135-139, November
December
Ul. Gussman, R. A., A. M. Sacco, and N. M. McMahon. Design and Calibration
of a High Volume Cascade Impactor. Journal of the Air Pollution Control
Association. Vol. 23 (No. 9): 778-782, September 1973.
k2. Hall, H. J., G. M. Varga, and E. M. Magee. Trace Elements and Potential
Effects in Fossil Fuels. Exxon Research and Engineering Company.
Publication Number EPA -650/2 -7U-118. Environmental Protection Agency.
October 197U. 35-^-7.
U3. Hemeon, Wesley C. L., and Arthur W. Black.' Stack Dust Sampling: In-
Stack Filter or E.P.A. Train. Journal of the Air Pollution Control
Association. Vol. 22 (No. 7) 516-518, July 1972.
UU- Hillenbrand, L. J., R. B. Engdahl, and R. E. Barrett. Chemical Composi
tion of Particulate Air Pollutants from Fossil-Fired Combustion Sources
Battelle Columbus Laboratories, Columbus, Ohio. Publication Number
PB 219009. Environmental Protection Agency. March 1973.
1+5. Hsieh, C. K. Andersen Sampler Evaluation. Joy Manufacturing Company
Research and Development Department. Report No. R-lll. January 1970.
18 p.
U6. Jacobs, Patricia A. A Random Measure for the Emission of Pollutants
by Vehicles on a Highway. Stanford University. Stanford, California.
Publication Number AD-758666. Office of Naval Research. February
1973. 29 P.
U7. Jones, Peter W., Robert D. Giammar, Paul E. Strup, and Thomas B. Stan.
Efficient Collection of Polycyclic Organic Compounds from Combustion
Effluents. Presentation at 68th Annual Meeting of the Air Pollution
Control Association, Boston, Mass., June 1975- 8 p.
U8. Karasek, F. W. Surface Analysis by Auger Spectroscopy. Research/
Development: U8-56, October 197U.
k?. Kessler, T., A. G. Sharkey, and R. A. Friedel. Analysis of Trace
Elements in Coal by Spark-Source Mass Spectrometry. Bureau of Mines,
Report of Investigation 77lU. 8 p.
125
-------
50. Klein, D. H., and P. Russell. Heavy Metal: Fallout Around a Power Plant.
Environmental Science and Technology. Vol. 7 (No. k): 357-358, April 1973.
51. Klingler, George A. Digital Computer Analysis of Particle Size
Distribution in Dusts and Powders. Energy Conversion Research Laboratory.
Wright-Patterson Air Force Base, Ohio. Publication Number AD-75209.
Aerospace Research Laboratory. August 1972. 92 p.
52. Lafferty, R. H., Jr., P. S. Baker, and Martha Gerrard. Measurement of
Sulfur Dioxide in Stack Gases: Design, Fabrication, and Test of Demon-
stration Instrument. Isotopes and Radiation Technology. Vol. 8 (No. k):
397 -403, 1971.
53. Ledbetter, Joe 0., and Birney R. Fish. The Jet Filter - A Single Stage
Size -Selective Sampler for Airborne Particulates . American Industrial
Hygiene Association Journal. February 1972.
5^. Lee, R. E., Jr., J. S. Caldwell, and G. B. Morgan. The Evaluation of
Methods for Measuring Suspended Particulates in Air. Atmospheric Environ-
ment (London). Vol. 6: 593-622, September 1972.
55- Lundgren, Dale A. An Aerosol Sampler for Determination of Particle Con-
centration as a Function of Size and Time. Journal of the Air Pollution
Control Association. Vol. 17 (No. ^) : 225-229, April 1967.
56. Lyon, W. S. Trace Elements Profiles Through a Coal-Fired Steam Plant,
Quarterly Progress Report for Period December, 1971 - March, 1972. Oak
Ridge National Laboratory, Oak Ridge, Tennessee, April 1972. 13 p.
57. Lyon, W. S. Trace Element Profiles Through a Coal -Fired Steam Plant -
A Quarterly Progress Report for Period July - October, 1972. Oak Ridge
National Laboratory, Oak Ridge, Tennessee, November 1972. 10 p.
58. Maugh, T. H. II. Trace Elements: A Growing Appreciation of Their
Effects on Man. Science. Vol. l8l: 253-25^, July 1973.
59. May, K. R. The Cascade Impactor: An Instrument for Sampling Coarse
Aerosols. Journal of Scientific Instruments. Vol. 22: 187-195, October
60. McCain, Joseph D., and Alvin N. Bird, Jr. Particle Size Distribution
Measurements of Atmospheric Haze Produced by a Large Stationary Source.
Southern Research Institute, Birmingham, Alabama, February 1972. 39 p.
6l. Mieure, J. P., and M. W. Dietrich. Determinations of Trace Organics in
Air and Water. Journal of Chromatographic Science. Vol. II: 559-570,
November 1973-
62. Morrow, N. L., R. S. Brief, and R. R. Bertrard. Air Sampling and
Analysis. Chemical Engineering/Deskbook Issue. May 1972.
126
-------
DeTel°£ffient= in SaJ°Pling and Analysis Instrumentation for
Poiiution contro1
6U. Ifetuach, D.F.S., J R Wallace, and C.A.Evans, Jr. Toxic Irace Elements
S^"1011 in EeSPirablC PartlCleS' *«**•• Vo1' 183:
65. Nilsen, Joan M. Next Pollution Problem: How to Monitor Emissions.
Chemical Engineering: 30-32, May 1971.
66. Northern Great Plains Resources Program Atmospheric Aspects Work Group
(Discussion Draft). December 197^.
67. Pacega, J. J. , T. M. Roberts, and R. E. Jervis. Particle Size Distribu-
tions of Lead, Bromine, and Chlorine. Environmental Science and Techno-
logy. Vol. 9 (No. 13): llkl.-l.lhk, December 1975.
68. Particulate Sampling Strategies for Mechanically Disturbed and Cyclonic
Flows. General Electric. Vol. 1, Technical Proposal. March 1973.
69. Pilat, Michael J., David S. Ensor, and John C. Bosch. Cascade Impactor
for Sizing Particulates in Emission Sources. American Industrial Hygiene
Association Journal. August 1971.
70. Preliminary Report of Coal Drill -Hole Data and Chemical Analyses of Coal
Beds in Campbell County, Wyoming. U. S. Geological Survey Open-File
Report 7^-97. U. S. Geological Survey and Montana Bureau of Mines and
Geology. 197U. 2kl p.
71. Ranweiler, Lynn E., and Jarvis L. Moyers. Atomic Absorption Procedure
for Analysis of Metals in Atmospheric Particulate Matter. Environmental
Science and Technology. Vol. 8: 152-156, February
72. Ranz, W. E., and J. B. Wong. Impaction of Dust and Smoke Particles.
Industrial and Engineering Chemistry. Vol. kk (No. 6): 1371-1381,
June 1952.
73. Robertus, R. J., K. L. Nielsen, C. T. Crowe, and D. T. Pratt. An
Attempt to Reduce NOX Emissions from Pulverized Coal Furnaces.
Environmental Science and Technology. Vol. 9 (No. 9): 859-862,
September 1975.
7^. Robles, Edward G., Jr. The Determination of Particle-Size Range in Fly
Ash from Stack Gases: Stoke 's Law - Settling Method. Regional Environ-
mental Health Laboratory. Publication Number AD-751 88U. U.S.A. Environ
mental Health Laboratory, April 1968. 9 P-
75. Ruch, R. R., H. J. Gluskoter, and N. F. Shimp. Occurrence and Distribu-
tion of Potentially Volatile Trace Elements in Coal. I11^°1;?^™, ,
Geological Survey, Urbana, Illinois. Publication Number EPA-650/2-7^-05^-
Environmental Protection Agency. July 197^- 9° P-
127
-------
76. Russ, J. C. Elemental X-Ray Analysis Materials (EXAM) Methods. Prairie
View, EDAX Laboratories, 1972. 89 p.
77. Russell, J. W. Analysis of Air Pollutants Using Sample Tubes and Gas
Chroma tography. Environmental Science and Technology. Vol. 9 (No. !3)-'
1175-1178, December 1975-
78. Sansone, Eric B., and Dietrich A. Weyel. A Note on the Penetration of a
Circular Tube by an Aerosol with a Log -Normal Size Distribution. Aerosol
Science. Vol. 2:
79. Savkisov, S. Size Distribution of Natural Aerosol Particulates. Trudy
Vysokogorny Geofizicheskey Institute (U.S.S.E. ). Department of the Army.
December 1972. 9 p.
80. Schlesinger, M. D., and Hyman Schultz. An Evaluation of Methods for
Detecting Mercury in Some U.S. Coals. Bureau of Mines, Report of Investi-
gation 7609. 11 p.
8l. Shannon, L. J., P. G. Gorman, and M. Reichel. Particulate Pollutant
System Study. Vol. II -Fine Particle Emissions. Midwest Research Institute.
Kansas City, Missouri. 'Publication Number PB-203521. Environmental
Protection Agency. August 1971. 335 p.
82. Shannon, L. J. Report for Period December 1-31, 197k, Utility Boiler
Emissions - Data Analysis. Midwest Research Institute. January 1975. 8 p.
83. Siegel, G. R. Particulate Technology - Project Coordination Meeting.
Tennessee Valley Authority, Chattanooga, Tennessee, February 197^.
Qk. Siegel, G. R. TVA-ORNL Investigation of Trace Element Material Balances
for Coal-Fired Steam Plants. Tennessee Authority, Chattanooga, Tennessee,
March 1973. 6 p.
85. Sinclair, David. A Portable Diffusion Battery. American Industrial
Hygiene Association Journal. Vol. 33 (No. 11): 729-735, November 1972.
86. Smith, Wallace B., Kenneth M. Gushing, and George E. Lacey. Andersen
Filter Substrate Weight Loss. Environmental Protection Agency. Publi-
cation Number PB-2^0 720. Southern Research Institute, Birmingham,
Alabama, February 1975. 2k p.
87. Sondreal, Everett A., Wayne R. Kube, and James L. Elder. Analysis of
the Northern Great Plains Province Lignites and their Ash: A Study of
Variability. Bureau of Mines, Report of Investigation 7158. August
1968. 25 p.
88. Standards of Performance for New and Substantially Modified Fossil Fuel-
Fired Steam Generators Greater Than 250 Million Btu Per Hour Heat Input.
Environmental Protection Agency, Bureau of Stationary Source Pollution
Control. 1971.
128
-------
89. Statnick, R. M., D. K. Oestreich, and R. Steiber. Sampling and Analysis
of Mercury Vapor in Industrial Streams Containing Sulfur Dioxide
Environmental Protection Agency. Research Branch Control Systems Labor-
atory. August 1973.
90. Strom, Lars. Transmission Efficiency of Aerosol Sampling Lines.
Atmospheric Environment (London). Vol. 6: 133-142, 1972.
91. Studies on Trace Metals. Environmental Science and Technology Vol 7
(Ho. 8): 684-686, August 1973.
92. Surprenant, N., R. Hall, S. Slater, T. Suza, M. Sussman, andC. Young.
Preliminary Environmental Assessment of Conventional Combustion Systems.
Vol. II. GCA Corporation, Bedford, Massachusetts. Publication Number
GCA-TR-75-26-G. Environmental Protection Agency. August 1975. 100 p.
93. Swanson, V. E., C. Huffman, Jr., and G. C. Hamilton. Composition and
Trace-Element Content of Coal, Northern Great Plains Area. Mineral
Resources Work Group Report. Department of Interior. February 1974.
94. Theis, T. L. The Potential Trace Metal Contamination of Water Resources
Through the Disposal of Fly Ash. University of Notre Dame. (Prepared
for 2nd National Conference on Complete Water Reuse. Chicago, Illinois,
May 4-8, 1975.) 20 p.
95. Trace Metal Contaminants. Dimensions/NBS. Vol. 57 (No. 10): 244-2^5,
October 1973-
96. Trace Metals: Unknown, Unseen Pollution Threat, C&EN, July 1971.
97. Tyler, Germund. Heavy Metal Pollution and Mineralization of Nitrogen
in Forest Soils. Nature. Vol. 255: 701-702, June 1975-
98. Vandegrift, A. E., L. J. Shannon, and P. G. Gorman. Controlling Fine
Particles. Chemical Engineering/Deskbook Issue. June 1973-
99. Weeter, D. W., J. E. Niece, and A. M. DiGioia, Jr. Environmental Manage-
ment of Residues from Fossil-Fuel-Fired Power Stations. University of
Pittsburgh. Presented at 1974 Annual Water Pollution Control Fiberation
Conference, Denver, Colorado. October 8, 1974. 22 p.
100. Wilson, J. S., andM. W. Redifer. Equilibrium Composition of Simulated
Coal Combustion Products: Relationship to Fireside Corrosion and Ash
Fouling. Journal of Engineering for Power. Vol. 96 (No. 2): 1*5-152,
April 1974-
129
-------
TECHNICAL REPORT DATA
(Please read hiitruc lions on the reverse before completing)
1. REPORT NO.
EPA-600/7-77-010
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Characterization of Ash from Coal-Fired
Power Plants
5. REPORT DATE
January 1977
6. PERFORMING ORGANIZATION CODE
7. AUTHOH(S)
8. PERFORMING ORGANIZATION REPORT NO
S.S. RayandF.G. Parker
PRS-18
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Tennessee Valley Authority
Power Research Staff
1320 Commerce Union Bank Bldg.
Chattanooga, Tennessee 37401
10. PROGRAM ELEMEN1
EHB557
NO.
11. CONTRACT/GRANT NO.
EPA-IAG-D5-E-721,
Subagreement 19
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
Milestone: 5/75-3/76
14. SPONSORING AGENCY CODE
EPA-ORD
is.SUPPLEMENTARY NOTES JERL-RTP Project Officer for this report is J.W. Jones, 919/549
8411 Ext 2915, Mail Drop 61.
16. ABSTRACT
The report summarizes existing data on the chemical and physical charac-
teristics of ashes produced by the burning of coal in steam-electric generating plants.
It summarizes several recent coal or ash characterization studies, emphasizing the
elemental chemical composition, particularly trace inorganic constituents. The
studies agree generally on partitioning of trace elements between bottom ash, fly ash,
and flue gas. The report examines coal and ash analysis methods, to aid in evaluating
and comparing results from studies that do not use identical analytical methods. The
need for a standard set of analytical procedures for coal and ash is evident. The
report also summarizes the physical and chemical characteristics of sulfur dioxide
scrubbing sludges, which are becoming a significant portion of total power plant
residues.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
Air Pollution
oal
Ashes
ludge
Analyzing
ombustion
Electric Power
Plants
Inorganic Compounds
Air Pollution Control
Stationary Sources
Characterization
13B
21D
21B
07A
14 B
10B
07B
8. DISTRIBUTION STATEMEN1
Unlimited
19. SECURITY CLASS (This Report)
Unclassified
20. SECURITY CLASS (This page)
Unclassified
21. NO. OF PAGES
139
22. PRICE
EPA Form 2220-1 (9-73)
130
------- |