United States
Environmental Protection
Agency
Industrial Environmental Researc
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S7-81 -076 May 1982
Project Summary
"
Environmental Assessment:
Source Test and Evaluation
Report— B&W Alliance
Atmospheric Fluidized-Bed
Combustor
. J. Kindya, R. R. Hall, C. W. Young, and P. Fennelly
A comprehensive emission sam-
pling and analysis program was con-
ducted on a pilot-scale, atmospheric-
pressure, coal-fired fluidized-bed
combustor (AFBC). Screening data
were obtained on organic and inor-
ganic pollutants to indicate biological
activity. Testing was conducted on the
Babcock and Wilcox/Electric Power
Research Institute pilot AFBC at
Alliance, OH (B&W-EPRI/Alliance).
This AFBC, with a coal firing capacity
of 880 kg/hr (1940 Ib/hr), was
designed to bridge the gap between
smaller bench scale units and the
larger, more expensive demonstration
plants.
To characterize uncontrolled air
emissions, trace element concentra-
tions were measured upstream of par-
ticulate controls. Assuming a control
efficiency of 99.9 percent, emissions
of trace element species would not be
a significant problem. This level of par-
ticulate control is achievable with con-
ventional particle control technology,
and is necessary to meet the utility
boiler Federal New Source Perfor-
mance Standard for paniculate emis-
sions of 13 ng/J (0.03 lb/106 Btu).
Elemental concentrations do not
appear to be significantly different
from other FBCs or conventional coal
combustion systems.
Air pollutant emissions of total
organics were less than for compara-
ble conventional combustion sys-
tems. Limited analyses for specific
polynuclear aromatic compounds
indicated that emissions of these com-
pounds are probably not of concern.
Analysis of laboratory-generated
leachates from solid waste samples
reveals that trace metal concentra-
tions are well below Federal hazard-
ous waste criteria.
Positive test results for mutagenic-
ity and cytotoxicity screening tests
require further investigation. Similar
bioassay results have been reported
for conventional combustion systems
and all other FBCs which have been
tested.
This Project Summary was devel-
oped by EPA's Industrial Environmen-
tal Research Laboratory, Research
Triangle Park, NC. to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
The development of fluidized-bed
combustion (FBC) has been supported
by the Federal government, private
industry, and utility groups because of
its potential advantages over conven-
-------
tional coal combustion methods. Reduc-
tion of S02 during the combustion
process is the primary advantage of
atmospheric FBC (AFBC) because it
eliminates the need for add-on flue gas
desulfurization equipment. AFBC also
reduces oxides of nitrogen (NOX) emis-
sions. Other advantages include a mod-
est reduction in capital costs compared
to a conventional coal-fired boiler and
the capability to burn a wide variety of
fuels including low grade fuels such as
anthracite culm, coal cleaning wastes,
and industrial wastes. Industrial sized
AFBC units are offered commercially by
several vendors.
In a fluidized-bed boiler, a mixture of
coal and limestone is supported on a
grid at the bottom of a boiler. Combus-
tion air is passed through the grid at
high velocities, typically 2.2 - 2.4 m/s(4
- 8 ft/s). The upward flow of the air
holds the solids in suspension, creating
a quasi-fluid that possesses many of the
properties of a liquid. The most impor-
tant liquid-like property to the boiler
designer is the fact that bed material is
exceptionally well mixed and flows
throughout the system without agita-
tion. This well mixed semiliquid state
produces high heat transfer rates and
permits combustion at temperatures of
760 - 930°C (1400 - 1700°F).
The comprehensive sampling and
analysis efforts discussed in this report
were based on a phased approach to
environmental assessment as devel-
oped by the Process Measurements
Branch of EPA's Industrial Environmen-
tal Research Laboratory at Research Tri-
angle Park, NC (IERL-RTP). The first
phase. Level 1, involves screening with
sampling and analytical techniques that
sacrifice accuracy and compound speci-
ficity to identify problem areas in a cost-
effective manner.' Level 1 should yield
final analytical results accurate within a
factor of ±3. These results can be used
to: (1) provide preliminary environmen-
tal assessment data; (2) identify prob-
lem areas; and (3) formulate the data
needed to rank energy and industrial
processes, streams within a process,
and components within a stream, for
further consideration in the overall
assessment. The second sampling and
analysis effort, Level 2, is directed by
Level 1 results and is designed to pro-
vide additional, more specific, accurate
and quantitative information that will
confirm and expand the data gathered in
Level 1. The primary focus of the sam-
pling and analytical efforts discussed in
this report was at Level 1. Some Level 2
analytical work was conducted.
Facility Description
and Streams Sampled
Figure 1 is a simplified drawing of the
B&W/EPRI AFBC. Crushed presized
coal and limestone are fed from separ-
ate storage bunkers into the common
transport system. The coal/limestone
feed mixture is transported pneumati-
cally to a splitter where the feed stream
is split into four separate lines. The com-
bustion bed consists of four equal 0.9 x
0.9 m (3 ft x 3 ft)quadrants, and one feed
line discharges into the center of each.
The resultant feedpoint/area ratio pro-
vides even distribution of fuel and.sor-
bent across the entire bed.
The furnace enclosureof the unitcon-
sists of atmospheric pressure water
walls with a fireside refractory lining.
Total height of the facility is 14.6 m (48
ft). Combustion air enters the plenum
and is forced through the distributor
plate and into the bed. During operation,
bed depth is maintained between 1.4
and 2 m (4.6 and 6.6 ft) and is cooled by a
serpentine arrangement of 11 tubes.
This in-bed tube bank keeps the bed
temperature between 780 and 870°C
(1440 and 1660°F). A convective tube
bank in the freeboard cools the combus-
tor flue gasto below 480°C(900°F). This
high freeboard improves combustion
efficiency while reducing the dust load-
ing to the primary dust collector
Paniculate laden flue gases exit the
combustor at the top and split into four
parallel streams in the primary multicy-
clone dust collector. Collected material
is dumped from a single hopper into
208-liter (55-gal.) drums on a continu-
ous basis and subsequently disposed of.
Although this material could have been
recycled to the combustor, it was not.
The flue gas leaving the cyclones
passes through a venturi f lowmeter and
is then cooled by a heat exchanger
before entering the baghouse for final
particulate removal. The baghouse is a
four-cell unit with a design filtration
velocity of 0.02 m/s (4 ft/min). Ash col-
lected in the baghouse is discharged to a
collection bin for disposal.
Spent bed solids are removed from
the combustor via five drain pipes that
extend down from the bed through the
distribution plate and plenum and dis-
charge into a water-cooled screw con-
veyor. Bed height and, therefore, rate of
spent bed material removal are con-
trolled by measurement of the pressure
drop across the bed.
Emissions testing at the B&W-
EPRI/Alliance AFBC facility was con-
ducted from December 10 to 14, 1979.
The system had operated at steady state
for several days before testing to ensure
stable bed conditions. Operating condi-
tions are presented in Table 1 as daily
averages for the 2 days when combus-
tor flue gas was sampled.
As shown in Figure 1, six streams
were sampled for chemical and biologi-
cal analysis. These streams were 1 -
combustor flue gas, gaseous
components, and entrained solids,
sampled by GCA; 2 - solids collected by
final particulate control device (bag-
house), sampled by B&W; 3 - solids col-
lected by the primary dust collector
(cyclones), sampled by B&W; 4 - spent
combustion bed solids, sampled by
B&W; and 5 and 6, coal and sorbent feed
streams, sampled by B&W. Because the
baghouse had only recently been
installed, ports to sample flue gases
after the baghouse were not available.
The sampling and handling procedures
were as specified in the IERL-RTP Level
1 procedures manual.1
Sampling and Analytical
Methodology
The Source Assessment Sampling
System (SASS) train was used to collect
size-fractionated particles, volatile and
nonvolatile organic compounds, and
trace metal components of the B&W-
EPRI/Alliance combustor flue gas
stream (stream 1 in Figure 1)for subse-
quent chemical and biological testing.
The SASS train collects particles in a
series of three cyclones with nominal
cut points of 10, 3, and 1 /urn. A filter
collects particles smaller than 1 t*m.
Organic species were captured by a
polymeric sorbent (XAD-2), in a
temperature-controlled trap. A series of
impingers follows the resin trap to cap-
ture volatile trace metals (Hg, As, and
Sb).
A modification to the standard SASS
methodology was the use of an air-
cooled probe to lower sample gas
temperature from 450°C (840°F) to
approximately 200°C (400°F). The parti-
cles were collected at 200°C (400°F)
while the XAD resin used for organic
collection was maintained below 35°C
(95°F).
Gaseous components of the B&W-
EPRI/Alliance flue gas stream were
sampled for subsequent analysis using
a combination of continuous withdraw-
al, grab sampling, and special impinger
-------
train techniques. Analyses were con-
ducted for CO, CO2, O2, N2, S02, H2S,
COS, methylmercaptans, ammonia, and
cyanide.
Solid streams (streams 2 to 6 in Fig-
ure 1) were sampled once per hour by
taking full-cut stream samples. Sam-
ples collected during each SASS train
were composited.
Inorganic constituents of B&W-
EPRI/Alliance stream samples were
quantified using a combination of
Table 1. Operating Conditions During the Test Program
Parameter Test 1 (12/10/79)
Test 2 (12/12/79)
Bed temperature. °C (°F)
Bed height, m (ft)
Fluidizing velocity, m/s (ft/s)
Coal type
Coal feed rate, kg/hr (Ib/hr)
Sorbent type
Sorbent fed rate, kg/hr (Ib/hr)
Coal (sorbent) size
Ca/S mole ration
840 (1550)
1.4 (4)
2.3 (7.5)
Pittsburgh No. 8, 2.4%
872 (1920)
Lowellville limestone
204 (450)
1/4x0(5/16x0)
2.58
840 (1550)
1.4 (4)
2.6 (8.4)
S, 12500Btu/lb
878 (1935)
272 (600)
3.37
Cleaned gases
to atmosphere /T\
instrumental and wet chemical
techniques.
The primary Level 1 inorganic analy-
sis technique is spark source mass
spectrometry, which provides sensitive
detection limits for about 70 elements.
Interferences, such as variations in the
ion source discharge conditions and the,
photoplate interpretation techniques
used in Level 1, provide only semi-
quantitative results accurate to within a
factor of 2 or 3.
B&W-EPRI/Alliance bulk solid
streams having the potential to be dis-
posed of in a landfill or other area where
leaching could occur (this included
spent bed material and cyclone catch)
were subjected to inorganic analysis of
both the solid material and laboratory-
generated distilled water leachates.
1
Baghouse
Primary H=»
Combustor
flue gas
dust -T
collector \ I
Cyclone ash
outlet
Baghouse solids
outlet
Fluidizing air i —»• J
Figure 1. Simplified drawing of the B&W/Alliance AFBC indicating sampling points.
-------
Atomic absorption spectrometry was
used to accurately quantify selected ele-
ments in the leachates.
The Level 1 test protocol attempts to
identify the major organic compound
classes within each sample stream
tested. Methylene chloride extracts of
the samples are analyzed. Qualitative
and some quantitative data are gener-
ated by the use of gravimetry, gas chro-
matography, liquid chromatography,
infrared spectroscopy, and low resolu-
tion mass spectrometry. These Level 1
techniques, m general, do not provide
data on specific compounds. Level 1
methods were supplemented with high
performance liquid chromatography
using fluorescence detection for poly-
nuclear aromatic compounds.
Volatile organics (boiling points below
100°C) are separated into six boiling
point ranges by onsite gas chromato-
graphy. Moderately volatile organics
(boiling points 100 - 300°C) in methy-
lene chloride extracts are analyzed in
the laboratory by gas chromatography.
Flame ionization detection is used in
both of the above cases. Nonvolatile or-
ganics (boiling point above 300°C) are
measured by gravimetric methods in
methylene chloride extracts. These or-
ganic concentration data provide some
qualitative indication of the types of
compounds that may be present
The Level 1 liquid chromatographic
(LC) separation technique wasdesigned
to separate samples into seven reason-
ably distinct classes of organic com-
pounds and was applied to all samples
that contained _a minimum of 15 mg
combined volatile and nonvolatile
organics. A sample was placed on a sil-
ica gel liquid chromatographic column,
and a series of eluants of sequentially
increasing polarity was employed to
separate into fractions for further
analyses.
Infrared analysis was used to deter-
mine the functional groups in an
organic sample or liquid chromatog-
raphy fraction of a partitioned sample.
The interpreted spectra provide in-
formation on functionality (e.g., car-
bonyl, aromatic hydrocarbon, alcohol,
amine, aliphatic hydrocarbon, halo-
genated organic).
Level 1 bioassays are designed as a
cost-effective initial screening tool that
indicates potential health or ecological
effects. As such, the test results should
be used to point out areas requiring
further investigation. Health effects
tests consisted of the Ames test for
mutagenicity, and mammalian cell cyto-
toxicity assays using rabbit alveolar
macrophages (RAM) and Chinese
hamster ovary (CHO) cells. Fathead
minnows, daphnids, and algae were the
organisms used to test for acute ecolog-
ical effects. Table 2 is the test matrix.
Results
Data Handling
Criteria or standards for air, water,
and solid waste pollutants are needed to
properly determine the implications of
test results. Federal standards exist for
some pollutants (e.g., total particulates,
NO*, and SO2) in boiler flue gases, and
Federal criteria are available to deter-
mine if a solid waste is hazardous. How-
ever, emission standards do not exist for
most of the pollutants measured in this
and other environmental assessment
programs.
IERL-RTP has developed a set of con-
servative Discharge Multimedia Envi-
ronmental Goa Is (DMEGs).2 These goals
are derived using models incorporating
available data such as industrial Thres-
hold Limit Values (TLVs), NIOSH recom-
mendations for worker exposure,
drinking water criteria, results of toxic-
ity experiments using animals, and
EPA/NIOSH ordering numbers or
animal data on carcmogenicity. These
DMEGs are emission concentrations
that are used in IERL-RTP research pro-
grams to provide perspective on poten-
tial environmental hazards, to provide
direction for control technology re-
search programs, and to rank emission
streams for future investigation. These
conservative goals are a screening tool
to provide focus for further, more de-
tailed investigations
The simplest model incorporates
TLVs as air pollutant emission goals.
Table 2.
Emission concentrations below the TLV
are assumed to be safe dispersion will
usually produce ground-level con-
centrations lower than stack concentra-
tions by a factor of 1000 or more. This
dilution factor, in general, should pro-
vide adequate protection for chronic ex-
posure of the general population The
other goals and models are based on
similar but more complex and, at times,
more tenuous extrapolations.
Measured trace element concentra-
tions for each stream sample were com-
pared to their individual DMEGs,
specific for the media of interest (air,
water, solid wastes). Elements in excess
of their DMEGs were "flagged," provid-
ing a mechanism to estimate potential
hazards associated with emission of
that stream. Such estimates may be
made to reflect both human health and
the ecological domain Elements in
excess of their DMEGs indicate a need
for further investigation.
Inorganic Analytical
Results
Particulate emissions from the B&W-
EPRI/Alliance AFBC were sampled
before the application of paniculate
control equipment. The particle size
results show that 80 percent by weight
were larger than 10 //m, 15 percent
were in the 3 to 10 fjm range, 4.4 per-
cent were in the 1 to 3 //m range, and
0.85 percent were smaller than 1 /urn.
Total paniculate concentration was 35 -
40 g/m3 which, at the measured excess
air, is equivalent to about 13,000 ng/J
(30lb/106Btu). Elemental analysis indi-
cates that much of the larger than 10/um
material was limestone elutriated from
the combustor.
Many elements in the combustor flue
gas exceeded their air DMEGs as might
Bioassay Testing of B&W-EPRI/Alliance Samples
Health effects testing
Cytotoxicity Ecological effects testing
Sample description
Mutagenicity
Ames
RAM
CHO
Fish Daphnids Algae
Combustor Flue Gasa
Fine f<3 fjm) particles
Coarse f> 3 fjm) particles
XAD extract (organics J
Bulk Solids
Cyclone catch
Spent bed material
y
y
y
c
y
y
y
y
y
—
yd
yd
— —
yd yd
/" /d
V V
a Collected by SASS train.
to(j) - this assay performed on the sample indicated.
c(—) - this assay not performed.
"Ecological effects testing was performed on laboratory-genfated distilled water
leachates of these two bulk solid streams.
-------
be expected from the extremely high
particle concentrations. Table 3 shows
emission concentrations for the 25 ele-
ments that exceeded their DMEGs. Also
shown in Table 3 are the discharge se-
verities (the ratio of the emission con-
centration to the DMEG) for each
element. The highest discharge severi-
ties are for vanadium 2700, chromium
2050, nickel 230, and phosphorous
160. Note that the DMEGs are based on
the assumption that the emissions are
in their most toxic form. For example,
the DMEG of 1/jg/m3 is based on hexa-
valent chromium; but if the emissions
were trivalent chromium, a goal of 50
/ug/m3 would be appropriate.
A full-scale utility boiler would be
required to reduce particulate emis-
sions by 99.9 percent from those mea-
sured at the B&W-EPRI/Alliance AFBC.
This collection efficiency is within the
Table 3. Trace Element Emissions in B&W-EPRI/Alliance Flue Gas
Compared to Emission Goals
Discharge Measured Discharge severity0
goal concentration
Element (ug/m3)* (ug/m3)'3 Uncontrolled Controlled
capability of conventional particulate
control devices. The effect of this emis-
sion reduction on trace elements would
depend on the distribution of trace ele-
ments by particle size, and on both the
type and fractional efficiency of the con-
trol device.
Discharge severities, assuming 99.9
percent control for all trace elements,
are also presented in Table 3. If this
assumption is valid, then only chro-
mium and vanadium would exceed their
goals. These estimates are consistent
with measurements at the Exxon Mini-
plant, a pressurized fluidized-bed com-
bustor.3
Emissions of NO? and S02 were conti-
nously monitored by B&W. Emission
rates for N02 were 172 ng/J (0.4 lb/106
Btu) and 224 ng/J (0.52 lb/106 Btu),
respectively, on the first and second
days of testing. The AFBC reduced
Lithium
Beryllium
Boron
Fluorine
Sodium6
Magnesium
Aluminum
Silicon
Phosphorus
Calcium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Selenium
Strontium
Yttrium"
Cadmium
Barium
Lead
Uranium
22
2
3,100
2.500
53,000
6,000
5,200
10,000
100
16,000
6,000
1
1
5,000
1.000
50
15
200
200
3,100
1,000
10
500
150
9
970
82
28,000
36.000
100,000
44,000
233,000
>454,000
16,000
> 74,500
73,000
2,700
2,050
10,300
> 78.000
690
3,450
1.360
445
8.450
1.100
17
7.650
830
74
44
41
9
14
2
7
4
45
160
5
12
2,700
2,050
2
>78
14
230
7
2
3
1
2
15
6
8
0.044
0.041
0.009
0.014
0.002
0.007
0.004
0.045
0.160
0.005
0.012
2.70
2.05
0.002
>0.078
0.014
0.23
0.007
0.002
0.003
0.001
0.002
0.015
0.006
0.008
*AII goals are air health DMEGs, except vanadium which is an ecological goal.
b Average of two test runs.
cDischarge Severity = measured concentration/DMEG. Uncontrolled means as
sampled at the cyclone inlet approximately 35 to 40 g/m3. Controlled assumes
particulate control of 99.9 percent which is sufficient to meet NSPS of 13 ng/J (0.03
lb/106 Btu) for utility boilers.
"Exceeds health DMEG in test day 1 samples only.
eExceeds health DMEG in test day 2 samples only.
emission by 79.6 percent to 395 ng/J
(0.92 lb/106 Btu) on the first day and by
67.2 percent to 980 ng/J (2.28 lb/106
Btu) on the second day. These emission
rates reflect only the operating condi-
tions on the test days and not the overall
capabilities of the B&W-EPRI/AFBC
system. Much lower emission rates
have been achieved under other operat-
ing conditions.
Leachates were generated from the
two solid waste streams that were avail-
able for analysis, cyclone catch and
spent bed material. A distilled water
method in accordance with Level 1
procedures was used Analytical results
show that most elements were below
detection limits of spark source mass
spectrometry, and were at least one to
two orders of magnitude below the
appropriate DMEG.
Calcium, nickel, and selenium
exceeded DMEGs in both leachate sam-
ples as shown in Table 4. Vanadium
exceeded the DMEG in the cyclone ash
leachate samples. The phosphorus
result which was higher than the ecol-
ogy DMEG of 0.5 /ug/l can be dropped
from further consideration because the
ecology goal is based on elemental
phosphorous and is thus not applicable
to AFBC. Calcium was far above the
DMEG and can be attributed to the
limestone in both waste streams. These
elements may require further study.
The leachate samples were also ana-
lyzed for arsenic, cadmium, chromium,
lead, mercury, and selenium by graphite
furnace atomic absorption spectrome-
try. This method was selected because
of the very low detection limits, 0.1 to 1
ppb (0.1 to 1 ug/\), and the accuracy.
Comparison of these results to hazard-
ous waste criteria shows that concen-
trations are well below the criteria (see
Table 5) used to determine if a waste is
hazardous.
Organic Analytical
Results
Organic species of potential concern
appear to be limited to the combustion
flue gas because organics in the other
samples are extremely low. Organics in
the flue gas particulate (fly ash) total 29
ug/m3 compared to 588 to 885/ug/m3 in
the flue gas (under the sampling condi-
tions used in the study). The two solid
waste streams, cyclone catch and spent
combustor bed, contain only 1.6/ug/g
and 7.6 ug/g of methylene chloride
extractable organics, respectively. A
comparison of these concentrations
with the goals for solid waste streams
-------
Table 4. Inorganic Trace Analysis of Laboratory Generated Leachates -
Elements that Exceed DMEGs
Emission
goal, fjg/l
Element
Phosphorous
Calcium
Nickel
Selenium
Vanadium
Health
15,000
240,000
230
50
2,500
Ecology
0.5
16.000
10
25
150
Concentration in
Cyclone solids
5
610,000
360
21 to 65
320
leachate, fjg/l
Spent bed material
:.s
610,000
220
76
50
Table 5.
Comparison of Trace Element Concentrations in B&W/Alliance
Leachates and EPA-Office of Solid Waste Criteria Identifying
Hazardous Solid Wastes
Cyclone catch
Spent bed material
Element
Arsenic
Cadmium
Chromium
Lead
Mercury
Selenium
Day 1
44*
0.3
6.0
<1.0
<1.0
66
Day 2
36
0.2
7.5
1.6
<1.0
41
Day 1
26
<0.1
19
<1.0
<1.0
21
Day 2
30
<0.1
20
<1.0
<1.0
41
OSW limits3'
5,000
1,000
5,000
5,000
200
1.000
"See Federal Register Volume 45, No. 98. Book 2, p. 33111, May 19. 1980.
*AII concentrations are in fjg/l.
indicates that these levels are not sig-
nificant and do not warrant further
study.
The significance of higher concentra-
tions of organics in the flue gas is diffi-
cult to evaluate because of the lack of
specific compound identification.
Results and the method used to evalu-
ate these results are illustrated in Table
6. Candidate organic compounds within
each boiling point range have been
compiled and categorized by Harris, et
al.4 for use in environmental assess-
ment programs. In the lowest boiling
point range, -160 to -100°C, a concen-
tration of 392 //g/m3 was measured.
Available data indicate that the only
compound that could be both present in
this fraction and that has a lower DMEG
is ethylene with a DMEG of 1 /ug/m3.
This result indicates that ethylene may
require further investigation, either test
work or an evaluation of process chem-
istry to determine if it could be present.
The second boiling point range -100 to
-50°C does not contain any compounds
of potential concern. The result for
these first two fractions demonstrates
that many compounds are not potential
problems and specific analyses are not
required. This illustrates the purpose of
the Level 1 approach. The list of organic
compounds of potential concern has
been narrowed from several hundred to
less than 20 as illustrated in Table 6.
Some caution, however, should be
observed in using Table 6 because of
uncertainty regarding the species to be
found in each fraction and potential
overlap between fractions.
A comparison between AFBC and
conventional results for total organics is
presented in Table 7. Uncontrolled
emissions from the B&W-EPRI/AFBC
Alliance are lower than those measured
from one conventional industrial boiler.
Limited Level 2 chemical analysis
was performed on selected B&W-
EPRI/Alliance samples. The initial Level
2 analysis involved screening selected
samples using High Performance Liquid
Chromatography (HPLC) with floures-
cence detection. This procedure pro-
vides low detection limits and is
especially useful for polynuclear aro-
matic hydrocarbons (PNAs). B&W-
EPRI/Alliance stream samples
analyzed by HPLC/flourescence include
combustor flue gas fine (<3 /L/m) and
coarse (>3 //m) particles, nonvolatile
organics (adsorbed on XAD-2, extracted
with CH2Cl2>, and cyclone hopper ash.
Appropriate blanks were also run, and
data were blank corrected.
Results of analysis of combustor flue
gas samples are shown in Table 8. Most
compounds are well below the approp-
riate DMEG. Only benzo(a)pyrene may
be present at a concentration near the
goal of 0.020 fjg/m3. However, this
compound cannot be differentiated
from the much less hazardous
benzo(e)pyrene, so its actual concentra-
tion may be below 0.02/yg/m3 in which
case none of the PNAs measured in the
flue gas exceed their DMEGs.
Bioassay Results
Table 9 summarizes test data from
bioassays of five effluent stream sam-
ples from the B&W-EPRI/Alliance
AFBC. Included are results of testing
three combustor flue gas samples and
two bulk solids (cyclone catch and spent
combustion bed material). Results are
shown as positive/negative for mutage-
nicity in S. typhimurium for the Ames
test, and as the appropriate toxicologic
parameter (LCso, ECso, etc.) for the re-
maining test. These data have been as-
sessed qualitatively using tire currently
recommended Level 1 criteria for bio-
assay response.
Of the five stream samples tested for
mutagenicity, only combustor flue gas
organics (XAD extract) had positive
response. Data reveal mutagenic activ-
ity for this sample in frameshift tester
strains TA 1537,1538, and 98. The low-
est recorded concentration (dose) that
elicited a positive response (LRPC) was
12 //g CH2CI2-extractable material. Rel-
ative mutagenic activity of this sample,
calculated using the number of rever-
tants at the LRPC for the most active
strain (TA 98), is eight revertants///g
organics.
Ames test data also reveal higher spe-
cific mutagenic activity in the absence
of S-9 microsomal mix. Addition of the
activation system generally reduces
mutagenic response, similar to results
observed from testing of Exxon PFBC
samples. These results indicate that
polynuclear aromatic hydrocarbons
(PNAs) cannot be the sole mutagenic
species responsible for the observed
activity. The very low levels of PNAthat
were measured by HPLC/flourescence
also indicate that other compounds
should be investigated.
Mutagenic activity in the Ames assay
is not a quantitative measure of
potential hazard to health or the
environment. The Ames assay is only
one of the battery of Level 1 screening
tests in which a positive response
indicates the need for further
investigation and analysis of the
sample. B&W-EPRI/Alliance Ames test
results can be compared with those
from other units, but absolute
judgments of the numerical
relationships of these results are not
-------
Table 6. Combustor Flue Gas Organic Analytical Results
Sample
fraction designation
Measured
emissions, fjg/m3
4
5
6
7
Paniculate
Coarse f>3 urn)
Fine (<3 (imj
10.4
17.2
110.8
144.7
no data
30
Organic compounds of
potential concern3
Gaseous - boiling point range^'4
-160 to -100°C
- 100 to -50° C
-50 to 0°C
0 to 30°C
30 to 60° C
60 to 90°C
90 to 100°C
Volatile liquid chromatography
1
2
3
4
5
6
7
Nonvolatile liquid chromatography fraction
1
2
3
392
<123
5,388
22,260
<294
<351
<408
0.8
0.9
1.8
not detectable
1.2
14.5
4.4
59.7
1.4
6.7
One-ethylene (ecological-base)
none
two - formaldehyde, vinyl chloride
none
one - acrolein
none
—
none
none
one - PCBs
none
one - N-nitroso dimethylamine
none
none
—
none
three, B(ajP, 1 ,2:5,6-dibenzanthracene.
3-methyl cholanthrene
none
none
one - dibenzo (c,g) carbazole
two - 2,4,6-trinitrophenol,
3,3-dichlorobenzidine
Insufficient information to assign
probable compound types
These organic compounds were not specifically detected in flue gas samples but they are within the indicated boiling point range.
Emission goals of these samples are below measured total emissions; therefore, they have the potential to be present.
Table 7. Emission of Total Organics from the B&W/Alliance AFBC Compared to a Conventional Coal-Fired Boiler
Organic emissions, /jg/m3
Conventional coal-firing
Organic component
Volatile (bp 100 - 300°C)
Nonvolatile fbp >300°Cj
Total organic component
B&W/ Alliance"
117
673
890
Scrubber inlet
810
5400
6210
Scrubber outlet
652
788
1440
a Average of two test runs.
meaningful. Test protocols vary
between laboratories, and even those in
the research field have not decided how
Ames data can best be presented to
facilitate just these types of
comparisons. However, a positive Ames
test response, using agreed-upon
criteria, is a valuable screening tool.
Bearing in mind the limitations
mentioned above, some comparisons
between Alliance results and other data
are still instructive. The result for TA 98
(8 fjg/g organic) is similar to that
calculated from the testing of a
comparable sample from the Exxon
Miniplant PFBC.3 All positive responses
detected were of the direct-acting
frame-shift category. Metabolic
activation did not enhance mutagenic
activity.
Mutagenic activity has recently been
reported in paniculate samples
obtained from other FBC units. Clark et
al.6 have obtained positive Ames
response in testing flyash samples from
the45.7-cm(18-in.)diameterFBCatthe
Morgantown Energy Technology
Center. Kubitschek and Williams7 have
reported mutagenic activity in fly ash
samples from an experimental 15-cm
(6-in.) diameter FBC operated at the
Argonne' National Laboratory. This
response was seen to vary in specific
activity at lower temperatures
presumably because of the increased
deposition of mutagenic species by
condensation mechanisms on particle
surfaces. The higher paniculate
sampling temperatures at B&W-
EPRI/Alliance would result in trapping
of volatilized substances by the XAD-2
resin.
It must be emphasized that the
positive mutagenic response observed
for these several FBC effluent streams
-------
is a result unique neither to FBC
processes nor to coal combustion
effluent streams in general. A survey of
the literature reveals that production of
atmospheric mutagens is not a
phenomenon limited to certain specific
air emission sources. Mutagenicity has
been reported in the Ames assay of
conventional combustion and ambient
air samples collected near various sites
both in the U.S. and elsewhere.
Of the four samples assayed, the fine
particles (<3 fim) from the combustor
flue gas stream elicited the highest toxic
response in RAM cells based on viability
index. The coarse paniculate (>3 /urn)
sample exhibited a relatively lower
toxicity. Several investigators have
demonstrated a direct relationship
between decreasing particle size and
increasing cytotoxic response. This is
corroborated by these data.
Three B&W-EPRI/Alliance samples
were assayed using the CHO test
system. Combustor flue gas XAD-
extract was the most active of the
samples tested. This sample caused 50
percent reduction in plating efficiency at
a concentration of only 1.2 //I/ml. This
response corroborates the biological
activity observed for this sample in the
Ames test.
Data indicate that both the cyclone
catch and bed reject samples were
Table 8. PNA Emissions from B&W-EPRI/Alliance AFBC Compared to DMEG
Emissions3
PNA species*
Naphthalene
Anthracene
Fluoranthene/P//-e/ie
Benz (a) anthracene/
Triphenylene/Chrysene
Benzo (k) fluoranthene
Benzo (a) pyrene/Benzo(e)pyrene
7,12-Dimethylebenzoanthracene,
1 ,2,3,4-Dibenzoanthracene
1.2,5, 6-Dibenzoanthracene
Indeno (1,2,3-cd) pyrene
Emission
goal (/jg/rrff
50,000
56,000
90,000
45
1,600
0.02
0.26
0.093
1,630
B&W-EPRI
Alliance
<2.6
<0.043
0.34
0.13
<0.0003
0.024
<0.078
<0.0022
0.34
a Represents gaseous emissions adsorbed on XAD-2 resin and extracted with
b Where two or more species co-elute, the emission goal of the most hazardous is
listed (underlined).
c Air, health Discharge Multimedia Environmental Goals (DMEGs).
highly toxic (less than 20 percent; see
Table 9) to fathead minnows at
concentrations of 12.3 and 13.5
percent, respectively. LCso values in the
daphnia test for both samples were
similar to those obtained in the fish
bioassay tests. The 48-hour LC50 values
for the bed reject and cyclone samples
were 12.3 and 10.7 percent,
respectively, which is considered high
toxicity High toxicity to algae was also
demonstrated by both samples.
Even though testing of leachates in
these ecological effects assays resulted
in uniformly high toxicity responses in
all tests for both leachate samples,
these results are of limited use. The
high toxicity was probably a result of
increases in pH, to levels fatal to the test
species. Although increased pH is a
valid endpoint to be measured in these
tests, toxicity resulting from increased
pH masks the effects that result from
chemical constituents of these leachate
samples.
Conclusions and
Recommendations
Air emissions of trace elements from
the B&W-EPRI/Alliance AFBC do not
appear to present a significant
environmental concern when these
emissions are evaluated using available
emission DMEGs. This conclusion is
based on particulate measurements
which were made before the use of any
control device and to which a "control
factor" of 99.9 percent was applied.
Measurements after a final particulate
Table 9. Results of Biological Testing of B&W/Alliance Effluent Stream Samples
Health effects testing
Mutagenicity Toxicity
Sample identification
Fine particles f<3 (im)
Coarse particles f>3 fjm)
Flue gas organics
Cyclone catch'
Spent bed material*
Ames RAM
(+/-f (LCsof
60
(MODf
785
(LOWf
+ NT
435
(LOW)"
295
(LOWf
CHO
(LCso)
NT
NT
1.2 (fjl/ml)
(HIGH)
142
(LOWf
358
(LOWf
Ecological effects testing
Fish
(LC50f
NT
NT
NT
12.3
(HIGHf
13.5
(HIGHf
Daphnia
(LCso)
NT
NT
NT
10.7
(HIGHf
12.3
(HIGHf
Algae
(LCso)
NT
NT
NT
8.7
(HIGHf
7.9
(HIGHf
"+/- = positive or negative mutagenic response.
b/.C50 reported as fig/ml except where indicated.
cLCso for fish tests is 96 hour; for Daphnia 48 hour.
"LOW = low toxicity; MOD = moderate toxicity; HIGH - high toxicity.
e NT = sample not tested in the indicated assay system.
leachates of these materials were tested in ecological effects tests.
a
-------
control device should be conducted to
confirm that 99.9 percent control can be
achieved.
The positive mutagenicity and
cytotoxicity results require some further
investigation. Additional bioassays and
chemical analyses are recommended.
References
1. Lentzen, D.E., D.E. Wagoner, E.D.
Estes, and W.F. Gutknecht. IERL-
RTP Procedures Manual: Level 1
Environmental Assessment
(Second Edition). Prepared by
Research Triangle Institute, Rea-
search Triangle Park, NC, for the
U.S. Environmental Protection
Agency. Report No. EPA-600/7-
78-201 (NTIS PB 293795),
October 1978.
2. Cleland, J.G. and G.L Kingsbury.
Multimedia Environmental Goals
for Environmental Assessment,
Volumes I and II. Prepared by
Research Triangle Institute,
Research Triangle Park, NC, for
the U.S. Environmental Protec-
tion Agency. Reports No. EPA-
600/7-77-136a and b (NTIS PB
296919 and 276920), November
1977.
3. Kmdya, R.J., R.R. Hall, G.H. Hunt,
W. Piispanen, and P.P. Fennelly.
Environmental Assessment:
Source Test and Evaluation
Report — Exxon Miniplant Pres-
surized Fluidized-Bed Combustor
with Sorbent Regeneration. Pre-
pared by GCA/Technology Div-
ision, Bedford, MA, for the U.S.
Environmental Protection
Agency. Report No. EPA-600/7-
81-077, April 1981.
4. Harris, J.C., M.J. Hayes," P.L
Levfns, and D.B. Lindsay.
EPA/IERL-RTP Procedures for
Level 2 Sampling and Analysis of
Organic Materials. Prepared by
Arthur D. Little, Inc., Cambridge,
MA, for the U..S. Environmental
Protection Agency. Report No.
EPA-600/7-79-033 (NTIS PB
293800), February 1979.
5. Leavitt, C., K. Arledge, W.
Hamersma, R. Maddalane, R. Bei-
mer, G. Richard, and M. Yamad.
Environmental Assessment of
Coal - and Oil-Firing in a Con-
trolled Industrial Boiler, Volumes
I, II, and III. Prepared by TRW, Inc.,
Redondo Beach, CA, for the U.S.
Environmental Protection
Agency. Reports No. EPA-600/7-
78-164a-c (NTIS PB 289942,
289941, 291236), August 1978.
Clark, C.R., R.L. Hanson, and A.
Sanchez. Mutagenicity of Efflu-
ents Associated with the
Fluidized-Bed Combustion of
Coal. Inhalation Toxicology
Research Institute Annual Report
1977-1978, pp. 274-284. Pre-
pared by Lovelace Biomedical and
Environmental Research Insti-
tute, Albuquerque, NM, for the
U.S. Department of Energy,
December 1978.
Kubitschek, H.E. and D.M.
Williams. Mutagenicity of Fly Ash
From a Fluidized-Bed Combustor
During Start-up and Steady Oper-
ating Conditions. Mutation
Research 77:287-291, 1980.
R. J. Kindya. R. R. Hall, C. W. Young, and P. Fennelly are with GCA/Technology
Division, Bedford, MA 01730.
John O. Milliken is the EPA Project Officer (see below).
The complete report, entitled "Environmental Assessment: Source Test and
Evaluation Report—B&W Alliance Atmospheric Fluidized-Bed Combustor,"
(Order No. PB 82-186 537; Cost: $12.00. subject to change) will be available
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
A U.S. GOVERNMENT PRINTING OFFICE: 1982-559-092/3412
9
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