United States
Environmental Protection
Agency
Environmental Monitoring Systems /
Laboratory \
Research Triangle Park NC 2771
Research and Development
EPA-600/S4-81-023 June 1981
Project Summary
Evaluation of Sampling
Techniques for Atmospheric
Emissions from Sintering in the
Iron and Steel Industry
Tests were conducted et two sin-
tering plants of the Iron and Steel
Industry to evaluate a test method
under consideration by the U.S.
Environmental Protection Agency
(EPA). In field tests, four modified
Method 5 sampling trains, operating
simultaneously at a single point in the
stack, yielded four samples per sam-
pling run. Each sample was analyzed
for front-half filterable particulates
and back-half organic solvent extract-
ables. In addition, the effects of filter
and probe temperatures on filter col-
lection efficiency, and the effects of
sample handling, storage conditions.
and recovery procedures on sampling
results were studied. Temperature
fluctuations from 65° -120°C (150° -
250°F) did not significantly affect the
particulate concentrations, nor did
additional desiccation greater than the
conventional time period. Chromato-
graphic experiments indicated that pH
7 was preferable for OSE extraction.
This Project Summary was devel-
oped by EPA's Environmental Moni-
toring Systems 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
This study was undertaken to evalu-
ate the proposed sampling methodology
to be used to measure the stack gas
concentration of particulate matter
found in the exhaust of the control
device from the sinter process windbox.
The sinter process converts finely
divided, iron-bearing materials, into a
granular material that can be put into
the blast furnace. These iron-bearing
materials are mixed with a limestone
flux, coal or coke, and-water to obtain a
composite material (burden) which is
put on a traveling grate. Combustion is
initiated to agglomerate the iron-bearing
materials into a granular material called
the sinter cake and at the end erf. the
traveling grate, the sinter cake is broken
into pieces and sent to the blast furnace.
The windbox is a compartment under
the traveling grate that promotes the
uniform distribution of combustion air
through the sinter bed. The windbox
exhaust gases pass through a control
device such as a bag house, a wet
scrubber, or an electrostatic precipitator,
and on into the stack.
Windbox emissions contain filterable
particulate and other materials that can
pass through the filter, such as NH4,
S02, S04, NO,, F, and condensible organic
materials. It is this nonfilterable portion
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that has caused the most difficulty in
measuring sinter emissions. Therefore,
this study sought to identify the problem
areas in measuring the particulate
component of these nonfilterable emis-
sions and to develop a consistent ana-
lytical approach that would yield an
acceptable measure of the total particu-
late (filterable and condensible particu-
late) from the sinter process windbox.
Experimental Design
Tests to evaluate the sampling me-
thodology were conducted at two facili-
ties. Because of the heterogeneous
mixture of sinter feed, it was recognized
that the reproducibility of sequential
samples would be difficult. To overcome
this problem, four simultaneous sam-
ples were taken during a run and the
sampling conditions were varied within
the run. For example, the filter tempera-
ture of trains A and B were kept at
120°C (250° F), while the filter tempera-
ture of trains C and D were kept at 65°C
(150°F). The analytical protocol specified
a number of experiments to evaluate the
measurement of condensible particu-
lates. Examples of these experiments
are: 1) variations in the pH of the
impinger solution, 2) effect of oven
drying the particulate, and 3) alternative
procedures to organic extraction is Total
Organic Carbon (TOC) analysis.
Sampling Equipment
The four-train sampling design was
composed of four complete EPA Refer-
ence Method 5(1) sets of apparatus. The
major modification to the sampling
system was locating all the probes,
filters and glassware in a single con-
tainer. This design modification allows
the use of a smaller test crew and
permits the sample probes to be located
in approximately the same place in the
stack. This same type of four-train
assembly is used in most Environmental
Monitoring Systems Laboratory (EMSL)
source method development testing.
Process Conditions
Sinter plant A was of a special design
having a much larger than usual process
feed rate but a smaller concentration of
condensible material. Process operating
conditions were more uniform and
emissions more consistent. Windbox
emissions were controlled by a high
energy venturi scrubber.
Sinter plant B was of a more conven
tional design in that it handled a variety
of scrap iron-bearing material. Feed rate
and operating conditions were more
variable. Testing was interrupted or
several occasions due to upsets on the
sinter process line. Windbox emissions
were controlled by a high energy venturi
scrubber.
Results
The field work resulted in a large
number of test samples. The samples
were analyzed and reported as three
fractions: filterable particulate (FP),
organic solvent extractable (OSE), and
impinger inorganics. The filterable
particulate catch is composed of the
material recovered from the probe and
filter of the train. The organic solvent
extractable catch is the residue left after
evaporation of the ether-chloroform
extraction of the impinger water solu-
tion. The impinger inorganic catch is the
residue remaining after evaporation of
the impinger water phase after extraction
by ether-chloroform. Analysis showed
the inorganic portion was primarily
sulfate. The results from sampling at
plants A and B are summarized in Tables
1 and 2.
Table 1. Statistical Results of Grouped Run Set Data (Plant A)
Run set*
1 A-C
2A.B
C,D
(150)
3A-DC
4A.B
C,D
(150)
5A-D"
6A-D*
7A.B
C.D
(1501
8A-D
Ff*
mg/sm3
35.28
28.05
19.38
30.23
25.13
15.53
29.40
27.47
24.89
27.18
28.92
Mean (x)
OSE
mg/sm3
6.05
3.41
2.65
3.68
5.16
4.77
4.07
3.82
6.87
3.55
3.84
Standard
deviation fSD)
Total
mg/sm3
38.63
31.46
22.48
33.20
30.29
20.30
34.96
31.70
31.76
30.74
32.76
FP
mg/sm3
3.35
O.35
1.80
1.78
2.60
5.28
4.07
4.18
1.60
9.02
2.28
OSE
mg/sm3
3.04
0.0
0.49
0.90
0.80
1.03
1.35
0.64
4.04
1.03
2.46
Total
mg/sm3
5.88
0.35
2.30
1.13
3.40
4.24
4.55
4.48
2.44
10.05
4.31
Coefficient of
variation
(CV=SD/x x 100)
FP
%
10
1
9
6
10
34
14
15
6
33
8
OSE
%
50
0.0
18
24
16
22
33
17
59
28
64
Total
%
15
1
10
3
11
21
13
14
8
33
13
*120°C (250°F) unless otherwise indicated by (150) for 65°C (150°F).
^Filterable particulates.
"Run C OSE invalid.
aRun B OSE invalid.
'Run A OSE invalid.
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Table 2.
Run sef"
1 A-D
2" A.B
C,D
A-D
3' A-D
A-C
4A,B
C.D
A-D
5A,B
C.D
A-D
tf C.D
A.B
A-D
B-D
7 C.D
A.B
A-D
Statistical Results of Grouped Run Set Data (Plant B)
Temperature
°C (°F)
120 (250)
120 (250)
65 (150)
120 (250)
120 (250)
120 (250)
65 (150)
120 (2501
65 (150)
120 (250)
65 (150)
120 (250)
65 (150)
FF*
mg/sm3
32.04
31.42
35.84
33.63
82.71
92.98
53.98
43.73
48.67
48.15
.55.21
51.68
33.06
67.42
50.24
50.07
34.61
42.38
38.50
Mean (x)
O55"
mg/sm3
20.94
—
1.83
1.79
38.07
47.43
42.74
22.38
31.70
27.04
9.93
3.84
6.88
9.07
7.26
8.85
8.05
Standard
deviation fSDJ
TotaF
mg/sm3
52.98
—
84.54
94. 76
92.05
90.79
91.42
70.53
86.90
78.71
42.99
71.26
57.12
59.14
41.87
51.23
46.55
FP
mg/sm3
1.20
9.26
9.61
8.12
20.8
4.32
15.27
4.76
11.10
0.14
4.74
4.91
14.62
23.59
25.74
31.23
6.80
7.83
7.48
OSE
mg/sm3
9.15
—
0.26
0.31
1.63
4.82
6.14
5.17
4.73
6.73
2.02
4.96
4.68
2.07
3.39
5.37
3.78
Total
mg/sm3
8.04
—
20.77
4.41
13.65
0.06
7.91
5.03
9.48
11.30
12.59
28.55
24.31
29.36
10.20
2.47
8.12
Coefficient of variation
fCV=SD/x x 100)
FP
%
4
29
27
24
5
28
10
22
0.3
9.
8.
44
35
51
20
18
19
OSE
%
43
14
14
25
23
47
Total
%
15
5
9
14
50
17
^Filterable paniculate.
^Organic solvent extractables.
CFP plus OSE.
^Outlier values for organics.
'FP acetone rinse for Run D presumed invalid.
'OSf for Run A presumed invalid.
Sampling-Temperature Effects
Because of condensible paniculate
material in the stack gas it had been
expected that more front-half material
and less OSE back-half material would
be collected if the filter temperature
were reduced. Data on separate collec-
tions at 120°C (250°F) and at 65°C
(150°F) could not be compared because
the process conditions and feed mate-
rials were not constant over the test
period of several days, but data on
simultaneous run sets, where samples
from the first two trains collected at
125°C (250°F) to 65°C (150°F) and
those from the other two collected at
125°C (150°F) were compared. At plant
A and plant B, reduction in the filtration
temperature from 120°C (250°F) to
65°C (150°F) did not cause the front-
half catch to increase significantly. A
temperature reduction sufficient to
cause a measurable condensation of
organics was not possible because
condensation of moisture from the gas
stream wet the filter, and the vapor
pressure of the materials (even at 65°C
(150°F)) was enough to prevent such
low concentrations of materials from
condensing on the filter.
Conclusions and
Recommendations
The data base collected in this study
was insufficient to provide definitive
answers to all the questions concerning
the measurement of condensible emis-
sions. However, EMSL has planned
future studies on the quantification and
identification of component's in the
condensible particulate fraction.
Analysis of the data from this study
provided clarification in the use of the
EPA Reference Method 5 sampling
systems at sinter plant windbox exhaust.
The major findings are discussed in the
following sections.
Therefore, it may be concluded that
temperature fluctuations from 120°C
(250°F) to 65°C (150°F) will not signifi-
cantly affect the particulate concentra-
tions by increasing the deposits of
condensible materials on the filter. It is
recommended that the standard EPA
Reference Method 5 filtration tempera-
ture of 120°C (250°F) be used.
pH Effects
The amount of OSE collected by a
Method 5 train is usually considerably
less than 100 mg, but the volume of
organic solvents usually exceeds 100
ml. Under these conditions, substantial
amounts of metal sulfates, nitrates, and
oxides can be dissolved by the organic
solvent (2). The amounts extracted
depend mainly on the solvent and on the
pH of the solution (3). The data on plant
A and plant B show that sequential
extractions at acid, neutral and basic
pH's cause materials to be collected
with each extraction. The OSE concen-
trations at plant A were determined
with the solution at pH 3. Chromato-
graphic experiments at plant B indicated
that pH 7 was preferable so the tests for
> US GOVERNMENT PRINTING OFFICE. 1961-757-012/7137
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OSE were conducted with the solution
at this pH. Therefore, it is recommended
that the impinger solution be adjusted to
pH 7 (4). ',
Alternative Condenser System
The glass condenser system tested at
plant A proved acceptable as an alterna-
tive to the standard impinger arrange-
ment for collecting condensible particu-
lates, although no advantages could be
found for using this method.
Drying-Temperature Effect
Filterable paniculate samples exposed
to elevated temperatures for fixed time
periods did not lose appreciable mass. In
this way, it was determined that filter
drying conditions have no serious effect
on sample loss. However, oven drying of
the filter was not recommended for the
general case since conventional 24-
hour desiccation was satisfactory.
Impinger Sulfate Content
The sulfates formed in the cooled
impinger water constitute a large portion
of the inorganic materials in the back-
half catch, although the sulfates found
there may possibly be byproducts of
sulfuric acid mist in the sintering process.
The inorganics in the back-half catch
were variable, and may include pseudo-
particulates which would not normally
form in ambient air. Because these
results were erratic and irreproducible,
the inorganic (nonextractable) portion of
the back-half catch should not be in-
cluded as part of the total catch.
General Conclusions on the
Use of the EPA Reference
Method 5 Employing the OSE
Catch
No problems were apparent with the
field use of EPA Reference Method 5 for
testing at the iron and steel industry
sintering plants. Precision of the data on
the filterable particulate catch was
roughly in line with test data using
Method 5; the coefficient of variation
(CV), which is the standard deviation
(SO) divided by the mean, was about 19
percent. The OSE results by themselves
present a different picture; there was
much more variation. These studies did
not specifically identify what caused the
lack of precision, but did demonstrate
that for grouped samples taken at the
same time from the same location in the
stack, the CV in the OSE catch varied
from 20 to 40 percent. Based on the data
from these two plants, the effect of the
OSE data variability was not significant
when total catch (filterable particulate
plus OSE) was calculated; in fact, for
some runs the precision of the total
catch was better than either the filterable
particulate or OSE alone. Therefore, the
use of the OSE catch in combination
with the filterable particulate catch does
not adversely affect the total catch and
the total catch can be used to estimate
the total particulate emitted.
References
1. 40 CFR Part 60, Appendix A, Deter-
mination of Particulate Emissions for
Stationary Sources, p. 143-160, July
1, 1979.
2. Grossjean, D. Solvent Extraction and
Organic Carbon Determinations in
Atmospheric Particulate Matter: The
Organic Extraction-Organic Carbon
Analyzer (OE-OCA) Technique. Anal.
Chem. 47. 797-805 (1975).
3. ASTM Standard Method D2778-70,
reapproved in 1974.
4. McGaughey, J. F., and D. E. Wagoner.
Special Analyses of Samples from
Sinter Plants in the Iron and Steel
Industry. EPA Contract No. 68-02-
2725, RTI/1487/64-01 F, January
1978.
This Project Summary was authored by staff of PEDCo Environmental, Inc.,
Cincinnati, OH 45246.
Thomas J. Logan is the EPA contact (see below).
The complete report, entitled "Evaluation of Sampling Techniques for Atmos-
pheric Emissions from Sintering in the Iron and Steel Industry," {Order No.
PB 81-175 911; Cost: $8.00, 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 contact can be reached at:
Environmental Monitoring Systems Laboratory
U.S. Environmental Protection Agency
Research Triangle Park. NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
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