Test Number
72-MM-27
Monsanto Chemical Company
Soda Springs, Idaho
PEDCo ENVIRONMENTAL
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Test Number
72-MM-27
Monsanto Chemical Company
Soda Springs, Idaho
Prepared by:
Robert S. Amick
Richard W. Gerstle, P.E.
PEDCo-Environmental Specialists, Inc.
Cincinnati, Ohio
Contract No. 68-02-0237, Task 15
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TABLE OF CONTENTS
Page Number
I. INTRODUCTION 1
II. SUMMARY OF RESULTS 5
III. PROCESS DESCRIPTION 23
IV. LOCATION OF SAMPLING POINTS 27
V. SAMPLING PROCEDURES 29
APPENDIX A - DATA SUMMARY OF S02/S03/
FLUORIDE, AND P2°5 RESULTS'
COMPUTER PRINTOUTS, AND
EXAMPLE CALCULATIONS
APPENDIX B - FIELD DATA
APPENDIX C - LABORATORY REPORT
APPENDIX D - TEST LOG
APPENDIX E - PROJECT PARTICIPANTS AND
TITLES
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I. INTRODUCTION
Under the Clean Air Act, as amended, the Environmental
Protection Agency is charged with the establishment of
performance standards for new installations or modifications
of existing installations in stationary source categories
which may contribute significantly to air pollution. A
performance standard is a standard for emissions of air
pollutants which reflects the performance of the best
emission reduction systems that have been adequately
demonstrated (taking into account economic considerations).
Tests Performed
A series of tests were conducted at the elemental phos-
phorus plant of Monsanto Chemical Company in Soda Springs,
Idaho during October 5 - 11, 1972. Fluoride, P2°5' S03 and
SO2 concentrations before and after the venturi scrubber
serving the slag tapping operation of the No. 8 electric
furnace were measured. Stack gas velocities, temperatures,
moisture content, and molecular weights were also determined
where applicable. Separate sets of three runs were made for
fluoride and PpO' determinations. However, each sample was
later analyzed by EPA for both fluoride and P2^5' resulting
in six determinations for each compound at each sampling
site. . —-'
- 1 -
-------
Table 1 summarizes the test locations, dates, and other
pertinent information pertaining to this test series.
All samples were analyzed by EPA.
Sampling Sites
Stack gases from the furnace slag tapping operation
were collected before and after the venturi scrubber, as
shown in Figure 1 at points D and E, respectively. Scrubber
water samples were taken at a tap in the recycle line a few
feet upstream of the scrubber recycle pump, as shown in
Figure 1.
- 2 -
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TABLE 1. SUMMARY OF EMISSION MEASUREMENTS
MADE AT MONSANTO CHEMICAL COMPANY IN
- SODA SPRINGS, IDAHO
Date
1972
10/5
10/6
10/9
10/10
10/10
10/11
Test
No.
1 & 2
3
1 & 2
3
1 & 2
3
Test
Site
No. 8 Furnace
Slag Tap Scrubber
Inlet and Outlet
\
f
Stack Gas Parameters
Velc
>
>city
r
Ter
V
np.
i
%H2°
i
r
Molec
i
. wt.
r
1
Emissions
Fluorides and
Visible Emission
"
P2°5 and Visible
Emission
"
so2 & so3
1
If
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EAST
SLAG
HOLE
HOOD
NORTH
SLAG
HOLE
HOOD
METAL
SLAG
HOLE
HOOD
SAMPLING
SITE D
VENTURI
SCRUBBER
STEAM
TOO psig
35-. 5".
I.D.
SAMPLING
SEPARATOR
SCRUBBER WATER
SAMPLING POINT
SCRUBBER
RECYCLE PUMP
MAKEUP
WATER
WASTE TO
SLAG BED
Figure 1. Number 8 phosphorus furnace slag tap scrubber sampling site,
Monsanto Chemical Company - Soda Springs, Idaho
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II. SUMMARY OF RESULTS -,
Fluoride, P»0 , and SO emission data and associated
5 ^^
stack gas flow parameters are presented in Tables 2 through
10. Complete sampling data and calculations are presented
in the appendices of this report. Emissions reported in
pounds per hour are during tapping only, not continuous
clock time.
The average interval between the slag taps during the
nine inlet-outlet tests was twenty (20) minutes, while the
average slag tap duration was ten (10) minutes, i.e., slag
tapping occurred for an average of twenty minutes per hour.
Since there were three separate slag-tap holes with separate
hoods and aspiration ducts, as illustrated in Figure 1, a
wide variation occurred in the emission data, as well as
the visible emission observations made during some of the
tests.
Tables 11, 12, and 13 summarize the average emission
results for the fluoride, P00 , and SO tests, respectively.
^ D X •
Tables 14 and 15 summarize the fluoride and P^O^ content of
" o
the scrubber water and process materials.
Fluoride Tests . . . _
The first Greenburg-Smith impinger plugged with parti-
culate matter after five minutes into the first fluoride test;
- 5 -
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TABLE 2: SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
NO. 8 FURNACE INLET AND OUTLET
RUN NO. 1 - FLUORIDES
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
Stack Volumetric Flow Rate - DSCFMk
Stack Volumetric Flow Rate - ACFMC
Percent Isokinetic
Percent Excess Air
Percent Capacity
Feed Rate - ton/hr
INLET
10-5-72
37.638
.99
125
19,825
27,340
104.6
OUTLET
10-5-72
24.699
2.09
84
20,295
26,208
73.5
Flourides
mg
gr/DSCF
gr/ACF
Ib/hr d
Ib/ton feed
efficiency,
P2°5
mg
gr/DSCF
gr/ACF
Ib/hr d
Ib/ton feed
efficiency,
33.74
.01383
.01002
2.350
3.38
.00211
.00163
.367
84.4
509.50
.20890
.15141
35.499
15.90
.00993
.00769
1.728
95.1
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92 in. Hg.
Actual cubic feet per minute
Emission rate during tapping
Based on emission rate, Ib/hr.
— 6 —
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TABLE 3 : SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
. NO. 8 FURNACE INLET AND OUTLET
RUN NO. 2 - FLUORIDES
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
Stack Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFMC
Percent Isokinetic
Percent Excess Air
Perc-ent Capacity
Feed Rate - ton/hr
INLET
10-5-72
38.107
.50
125
21,032
28,867
103.9
OUTLET
10-5-72
26.854
3.03
83
21,134
27,480
76.8
Flourides
mg
gr/DSCF
gr/ACF
Ib/hr d
Ib/ton feed
efficiency, %(
P2°5
mg
gr/DSCF
gr/ACF
Ib/hr d
Ib/ton feed
efficiency, %
42.73
.01730
.01260 "„
3.119
1.070
.00061
.00047
.111
96.4
448.50
.18163
.13230
32.744
11.20
.00643
.00494
1.165
96.4
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92 in. Hg,
c
Actual cubic feet per minute
Emission rate during tapping
e Based on emission rate, Ib/hr.
— 7 —
If.
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TABLE 4 : SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
NO. 8 FURNACE INLET AND OUTLET
RUN NO. 3 - FLUORIDES
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
Stack Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate
Percent Isokinetic
Percent Excess Air
Percent Capacity
Feed Rate - ton/hr
ACFM
INLET
10-6-72
36.409
0.00
147
18,794
26,599
108.4
OUTLET
10-6-72
32.569
0.00
77
21,328
26,547
77.8
Flourides
mg
gr/DSCF
gr/ACF
lb/hrd
Ib/ton feed
efficiency, %(
P2°5
mg
gr/DSCF
gr/ACF
lb/hrd
12>/ton feed
efficiency, %
13.32
.00564
.00399
.909
1.50
.00084
.00067
.154
174.00
.07375
.05213
11.880
83.1
12.60
.00707
.00568
1.295
89.1
d
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92-in. Hg,
Actual cubic feet per minute
Emission rate during tapping
Based on emission rate, Ib/hr.
_ Q _
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TABLE 5: SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
NO. 8 FURNACE INLET AND OUTLET
RUN NO. 1 -
P2°5
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
Stack Volumetric Flow Rate - DSCFMh
Stack Volumetric Flow Rate - ACFMC
Percent Isokinetic
Percent Excess Air
Percent Capacity
Feed "Rate - ton/hr
INLET
10-9-72
32.689
0.43
137
18,197
25,444
103.8
OUTLET
10-9-72
33.550
1.90
75
20,045
25,360
101.1
P2°5
mg
gr/DSCF
gr/ACF
lb/hrd
Ib/ton feed
efficiency, %e
Fluorides
mg
gr/DSCF
gr/ACF
Ib/hr d
Ib/ton feed
Percent impinger catch
Q
efficiency, %
226.0
.1067
.0748
16,640
15.2
.00699
.00552
1.201
17.69
.00835
.00585
1.302
92.8
94.9
.860
.00039
.00031
*-067
b
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F/ 29.92 in. Hg.
Actual cubic feet per minute
Emission rate during tapping
e Based on emission rate, Ib/hr.
- 9 -
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TABLE 6: SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
NO. 8 FURNACE INLET AND OUTLET
RUN NO. 2 - P 0
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
Stack Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFM°
Percent Isokinetic
Percent Excess Air
Percent Capacity
Feed 'Rate - ton/hr
INLET
10-9-72
30.204
1.27
106
15,246
20,372
118.3
OUTLET
10-9-72
32.770
4.01
83
19,559
25,657
101.2
P2°5
mg
gr/DSCF
gr/ACF
Ib/hr d
Ib/ton feed
efficiency, %e
Fluorides
mg
gr/DSCF
gr/ACF
Ib/hr d
Ib/ton feed
Percent impinger catch
efficiency, %
274.20
.14010
.10478
181308
32.10
.01511
.01148
2:534
97.46
.04979
.03724
6.507
86.2
7.29
.00343
.00261
.575
91.2
d
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92,,In. Hg.
Actual cubic feet per minute
Emission rate during tapping
V Based on emission rate, Ib/hr.
- 10 -
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TABLE 7: SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
NO. 8 FURNACE INLET AND OUTLET
RUN NO. 3 - P°
INLET
OUTLET
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
Stack Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFMC
Percent Isokinetic
Percent Excess Air
Percent Capacity
Feed Rate - ton/hr
10-10-72
29.668
. 86
149
18,089
25,939
103.8
10-10-72
34.650
3.09
82
20,005
25,996
104.7
P2°5
mg
gr/DSCF
gr/ACF
lb/hrd
Ib/ton feed
Q
efficiency, %
Fluorides
mg
gr/DSCF
gr/ACF
Ib/hr d
Ib/ton feed
Percent impinger catch
Q
efficiency, %
231.4
.12036
.08394
18.662
17.9
.00797
.00613
1.367
30.7
.01596
.01113
2.475
92.7
2.35
.00104
.00080
.179
92.8
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92-In, Hg.
Actual cubic feet per minute
Emission rate during tapping
Based on emission rate, Ib/hr.
- 11 -
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TABLE 8: SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
.NO. 8 FURNACE INLET AND OUTLET
RUN NO. 1 - SO
X
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
5uack'Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFM°
Percent Isokinetic
Percent Excess Air
Percent Opacity
Feed Rate - ton/hr
INLET
10-10-72
31.752
2.42
143
17,811
25,691
106.4
OUTLET
10-10-72
34.812 .
1.75
80
19,955
25,445
105.4
SO3
mg
gr/DSCF
gr/ACF
Ib/hr d
ppm
Ib/ton of feed
efficiency, %
352.50
.17132
.11872
26.155
125
3.600
.00159
.00125
.27
1.2
99.'0
mg
gr/DSCF
gr/ACF
Ib/hr d
ppm
Ib/ton of feed
<•>
efficiency, %
60.20
.02925
.02027
4.5
25
e
e
-e
e
e
Dry standard cubic feet at 70°F, 29.92 in. Hg. ~-/
Dry standard cubic feet per minute at 70°F, 29.92 in. Hg,
Actual cubic feet per minute
Emission rate during tapping. " -•-, , -
S0~ concentration unavailable - no reproducible value could
be obtained due to interferences.
Based on emission rate, Ib/hr.
- 12 -
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TABLE 9: SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
NO. 8 FURNACE INLET AND OUTLET
RUN NO. 2 - SO:
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
3Lack'Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFM°
Percent Isokinetic
Percent Excess Air
Percent Opacity
Feed Rate - ton/hr
INLET
10-10-72
33.453
3.76
144
18,587
27,258
107.5
OUTLET
10-10-72
34.558
3.15
79
19,519
25,190
107.0
mg
gr/DSCF
gr/ACF
lb/hrd
ppm
Ib/ton of feed
g
efficiency, %
108.50
.05005
.03415
8.0
36
7.80
.00348
.00270
.58
2.5
92.8
mg
gr/DSCF
gr/ACF
Ib/hr d
ppm
Ib/ton of feed
efficiency, %e
37.80
.01743
.01189
2.8
15
36.40
.01625
.01260
2.7
14
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92 in. Hg,
Actual cubic feet per minute
Emission rate during tapping . .. . .
Based on emission rate, Ib/hr .
- 13 -
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TABLE IQ: SUMMARY OF EMISSION DATA
MONSANTO - SODA SPRINGS, IDAHO
NO. 8 FURNACE INLET AND OUTLET
RUN NO. 3 - SO
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
•ZLack-Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFM°
Percent Isokinetic
Percent Excess Air
Percent Opacity
Feed Rate - ton/hr
INLET
10-11-72
28.001
2.86
116
19,324
26,763
102.4
OUTLET
10-11-72
30.896
2.92
83
18,825
24,385
108.4
S03
mg
gr/DSCF
gr/ACF
Ib/hr d
ppm
Ib/ton of feed
efficiency, %
SO,,
mg
gr/DSCF
gr/ACF
lb/hrd
ppm
Ib/ton of feed
efficiency, %
150.00
.08267
.05970
13.7
60
10.50
.00524
.00404
.85
3.8
96.60
.05324
.03844
8.8
46
60.20 ...
.03006
.02319
4.9
26
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92 in. Hg,
Actual cubic feet per minute
Emission rate during tapping
Based on emission rate, Ib/hr
- 14 -
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TABLE 11. AVERAGE EMISSION RESULTS FOR
FLUORIDE TESTS
1-3
INLET
OUTLET
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
v
Stack Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFM
Percent Isokinetic
Percent Excess Air
Percent Capacity
Feed Rate - ton/hr
132
19,884
27,602
N.A.
N.A.
N.A.
81
20,919
26,745
N.A.
N.A.
N.A.
Flourides
mg
gr/DSCF
gr/ACF
lb/hrd
Ib/ton feed
efficiency, %
P2°5
mg
gr/DSCF
gr/ACF
lb/hrd
Ib/ton feed
efficiency, %
. .01226
.00887
2.1
-90.0
.15476
.11195
26.708
.00119
.00092
.21
.00781
.00610
1.396
94.8
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92 in. Hg.
£*
Actual cubic feet per minute
Emission rate during tapping
6 Based on average emission rate, Ib/hr.
- 15 -
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TABLE 12. AVERAGE EMISSION RESULTS FOR
P O TESTS
INLET
OUTLET
Date
Volume of Gas Sampled - DSCFa
Percent Moisture by Volume
Average Stack Temperature - °F
Stack Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFM°
Percent Isokinetic
Percent Excess Air
Percent Capacity
Feed Rate - ton/hr
131
17,177
23,918
N.A.
N.A.
N.A.
80
19,870
25,671
N.A.
N.A.
N.A.
P2°5
mg
gr/DSCF
gr/ACF
lb/hrd
Ib/ton feed
efficiency,
Fluorides
mg
gr/DSCF
gr/ACF
lb/hrd
Ib/ton feed
efficiency,
.12239
.08784
17.87
90.4
.02470
' .01807
3.43
.01002
.00771
1.70
.00162
.00124
.274
92.0
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92 in. Hg.
Actual cubic feet per minute
Emission rate during tapping
Based on average emission rate, Ib/hr
- 16 -
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TABLE 13. AVERAGE EMISSION RESULTS FOR
SO TESTS
Xl-3
INLET
OUTLET
Date
Volume of Gas Sampled - DS"CFa
Percent Moisture by Volume
Average Stack Temperature - °F
Stack Volumetric Flow Rate - DSCFM
Stack Volumetric Flow Rate - ACFM°
Percent Isokinetic
Percent Excess Air
Percent Opacity
Feed Rate - ton/hr
134
18,574
26,571
N.A.
N.A.
N.A.
N.A.
81
19,433
25,007
N.A.
N.A.
. N.A.
N.A.
SO3
mg
gr/DSCF
gr/ACF
Ib/hr
ppm
Ib/ton of feed
efficiency, %e
SO,,
mg
gr/DSCF
gr/ACF
Ib/hr
ppm
Ib/ton of feed
£i
efficiency, %
. .10135
.07086
15.95
74
.00344
.00266
.567
2.5
-96.6
.03331
.02353
5.4
28.7
.02316
.01790
3.8
20.0
29.6
Dry standard cubic feet at 70°F, 29.92 in. Hg.
Dry standard cubic feet per minute at 70°F, 29.92 in. Hg,
Actual cubic feet per minute
d
Emission rate during tapping
e Based on average emission rate, Ib/hr
- 17 -
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TABLE 14, SUMMARY OF SCRUBBER
WATER ANALYSES FOR FLUORIDES AND P
TEST
DATE
00
I
1-Fluorides- 10/5/72
2-Fluorides 10/5/72
3-Fluorides 10/6/72
i-p2o5
2-P205
3-P2°5
10/9/72
10/9/72
10/10/72
SCRUBBER WATER
FLUORIDES (MG/L)
a,b
(01
a,b
125.2°
124.0 (outlet to lake)
168.9
98.9a/1
399.r
1000b
268. £
CONCENTRATIONS
P0 (MG/ML)
3.5a'b
1.8 (outlet to lake
3.7
2.7
a,b
a,b
14.3^
S>
a) Average concentration of 2 samples taken
b) See Figure 1 for scrubber water sample location.
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TABLE 15. SUMMARY OF PROCESS
MATERIAL ANALYSES
RAW MATERIAL
DATE
TOTAL FLUORIDES
TOTAL
vo
I
Silica Sand
Phosphorus Nodules
Coke
Precipitator Dust
10/6/72
10/6/72
10/10/72
10/6/72
10/9/72
< .0 6 mg/gm
2.63% (by weight)
2.80% (by weight)
7 . 5 mg/gm
27.4% (by weight)
28.9% (by weight)
<.1% (by weight)
26.1%
a) Represents average of 2 samples
-------
consequently, the Greenburg-Smith impinger was replaced with
a modified straight tip impinger, which alleviated this
plugging for the rest of the test. The modified tip first
impinger was used throughout the remaining eight tests at
the inlet site.
Particulate concentration at the inlet site was observed
to vary widely throughout the nine tests.
The percent isokinetic values for the scrubber outlet
fluoride tests were low, averaging 76.03%, because the moisture
had been assumed to be approximately 20%, when it was actually
less than 2 percent.
A ferrophos tap occurred for 12 minutes during the third
fluoride test. This tap yielded visible emissions which were
similar to the ordinary slag taps' visible emissions.
The rest of the fluoride tests were run without incident.
The average inlet fluoride emission rate was 2.1 Ibs/hr and
the outlet was .21 Ib/hr. The scrubber'therefore removed,
90.0% of the fluorides on the average.
Opacity readings of visible emissions recorded during the
three fluoride tests are included in Appendix A, Field Data.
The individual average - weighted opacities for these three
- 20 -
-------
test periods were: Test 1: 14.1%; Test 2: 14.9%; Test 3:
12.0%; the average opacity for the three tests was 13.7%.
P_0._ Tests
—2—5
The relatively low P^Oc an<3 fluoride concentrations in
Test 1 (when compared with the other P?0 tests) confirmed
the following observations made during the first P?0,- test:
1. Opacity of the scrubber outlet stack exhaust was considerably
less than that observed for the three previous fluoride tests;
2. Dust concentration was about 25% of that observed during
the other tests, as evidenced by the lack of appreciable
particulate build-up on the fiberglass inlet filter and visual
observation of the inlet gas stream.
A ferrophos tap occurred for 18 minutes ..during P.. 0^
Test No. 2. This tap yielded visible emissions which were
similar to the ordinary slag taps' visible emissions.
The third PpO^ test was run without incident. The average
P00 emission rate for the three tests was 17.9 Ib/hr at the
5
inlet and 1.7 Ib/hr at the outlet, yielding an average'scrubber
efficiency of 90.4%.
S£ Tests
SO tests were made with a single traverse through one
port, at both the inlet and outlet, as space restrictions
- 21 -
-------
precluded traversing through both ports with a rigid probe.
All tests were made under apparently ordinary conditions.
Average concentrations for SO before and after the
•scrubber were 74 and 2.6 ppm respectively. The SO,, average
concentrations were 29 and 20 ppm at the inlet and outlet
respectively.
- 22 -
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III. PROCESS DESCRIPTION
Elemental phosphorus is produced from phosphate rock by
reduction in an electric arc furnace. Typical ores contain
10-13% phosphorus so that about 10 tons of rock must be
processed per ton of phosphorus produced. Considerable
quantities of coke, silica, and recycled materials are fed to
the furnaces with the beneficiated ore.
Prior to being fed to the furnace, the rock is agglomerated
and heat-hardened in a kiln. The partially fused product is
cooled and crushed to a specified size before being fed to
the furnace as shown in Figure 1.
Phosphate feed is carefully proportioned with silica and
coke before being transferred to feed bins directly above the
furnace. The feed mixture then moves by gravity from the bins
down into the furnace as the furnace feed is consumed.
The reaction within the furnace is approximated by the
following equation:
2 Ca3 (P04)2 + 10 C + 6 Si02 (230Q-2700°|2. ?4 + 10 C + 6 CaSi03
Elemental phosphorous and carbon monoxide leave the
furnace as gases. Dust is removed from the stream by an
electrostatic precipitator and the phosphorous vapor is later
condensed out in direct-^contact water condensers. W;aste CO
gas is used as a fuel in the kiln operation.
- 23 -
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The molten process by-products and some coke must be
periodically removed from the furnace by tapping. This
molten material separates into two layers inside the furnace.
The lighter top layer is a slag from the ore material. This
slag has no economic value except as an aggregate. It is
tapped alternately from two tapholes at 15-minute intervals.
The slag runs out into water-filled pits behind the furnace
building.
i
The heavier bottom layer is about twice the density of
the slag, and is largely a phosphorous-iron mixture known as
ferrophos. This metal by-product is tapped from the furnace
twice each day. The ferrophos is poured into chills and
then shipped to a nearby plant for vanadium redovery.
The tapping of slag and ferrophos results in the evolution
of significant amounts of fumes, most of which are P^O,-
particulates.
The No. 8 furnace at Monsanto's Soda Springs, Idaho
plant has been partially controlled since 1971 by a taphole-
hooding system vented to a scrubber.
Each of the three tapholes is hooded by a completely
enclosed box. Each box is refractory lined with outside
dimensions of 8' x 6' x 7". The refractory lining is necessary
- 24 -
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to prevent warping of the metal shell from the intense heat.
There are access ports and doors on the hoods which are
usually kept closed. However, even when the doors are open,
fume pickup is very effective within the hooded area. There
is no hooding over the slag runners or at the chill line or
metal well.
A three-foot diameter duct directs the fumes from each
;
hopd to the control device. Each duct has interior water
sprays for cooling purposes and dampers to control draft on
each hood. Usually, two ducts are open and one is closed.
The intake velocity across the access ports is approximately
700 feet per minute.
The three ducts join and lead to a high pressure-drop
venturi scrubber. Water is sprayed from nozzles on each side
of the throat at 370-420 gpm, depending on the amount of
water being sprayed into the ductwork prior to the scrubber.
The pressure drop across the scrubber is maintained at 48-52
inches of water. From the scrubber the exhaust stream enters
a cyclonic separator. The removed water is recirculated
from the bottom of the separator back to the venturi throat;
Make-up water is added at a fate of 30-40 gallons per minute.
From the separator, the cleaned gas is exhausted through an
induced-draft fan to a 175' fiberglass stack to the atmosphere.
- 25 -
-------
During testing, the furnace and scrubber control system
were operating normally and at rated capacity.
- 26 -
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IV. LOCATION OF SAMPLING POINTS
Figure 2 shows the sampling ports and the number of
sampling points at the inlet and outlet sites used to determine
the emissions from the slag tapping process. The inlet site
was located in a 35.5-inch round horizontal duct, and samples
here were collected at 48 points (24 along each diameter) of
a vertical and a horizontal port. This inlet port location
(Figures 1 and 2) does not conform to requirements of the
Federal Register , which specifies a minimum sampling distance
from obstructions of two (2) duct diameters and one-half (1/2)
duct diameter upstream and downstream of the sampling port
respectively. The site was nonetheless used because it was
the only available location for sampling. As shown, outlet
samples were extracted at 12 points (6 along each diameter)
from two ports in a 36-inch round vertical stack 48' above
the slag tap scrubber exhaust fan.
Federal Register, Vol. 36, No. 247, December 23, 1971
- 27 -
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INLET
SAMPLING
PORTS
\>
f IV
• 35. .5" rf
4
,1
VENTURI
SCRUBBER
1
— 1
TO SEPARATOR
•44
00
I
NO. 8 PHOSPHORUS FURNACE
SLAG TAP SCRUBBER INLET
TRAVERSE POINT DISTANCES
FROM INSIDE OF STACK, inches
il .
2.
3.
4.
5.
6.
7.
8.
9.
10.
11 .
12.
0.4
1 .1
2.0
2.8
3.7
4.7
5.7
6.9
8.2
9.7
11.5
14.1
13.
14.
15.
16.
17.
18.
19.
20.
21 .
22.
23.
24.
21 .4
24.0
25.8
27.3
28.6
29.8
30.8
31 .8
32.7
33.6
34.4
35.1
OUTLET
SAMPLING
PORTS
FROM
SEPARATOR
O
36"
50'
48
FAN
TRAVERSE POINT DISTANCES
FROM. INSIDE
OF STACK, inches
1. 1.6
2. 5.3
3. 10.6
4. 25.4
5-. 30.7
6. 34.4
NO. 8 PHOSPHORUS FURNACE
SLAG TAP SCRUBBER OUTLET
Figure 2. Slag tap scrubber sampling sites and location of sampling points-
Monsanto Chemical Company
-------
V. SAMPLING PROCEDURES •
All sampling procedures were selected by EPA prior to
field sampling. All analysis of collected samples were also
performed by EPA. Field data sheets were submitted to EPA
at the test site.
Velocity and Gas Temperature
All gas velocities were measured with a type S pitot
tube and inclined draft gage. In all cases velocities were
measured at each sampling point across the stack diameter to
determine an average value according to procedures described
in the Federal Register - Method 1. Temperatures were
measured by long stem dial thermometers.
Molecular Weight
An integrated sample of the stack gases was collected
during each run by pumping gas into a Mylar plastic bag at the
rate of approximately 0.5 liter per minute. This bag sample
was then analyzed with an Orsat apparatus for C0» and 0? as
described in the Federal Register, December 23, 1971, in
Method 3.1
Fluorides
The basic train for total fluoride samples, as shown in
Figure 3, consisted of three standard Greenburg-Smith impingers
Federal Register, Vol. 36, No. 247, December 23, 1971.
- 29 -
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V3^>
(jO
o ;
NOZZLE-
GLASS PROBE
FLEXIBLE
TEFLON
CONNECTOR
PAPER
FILTER
THERMOMETER
STACK WALL
PITOT
TUBE £
DRAFT
GAUGE
G-S IMPINGERS
NOTE:
FIRST IMPINGER CHANGED
TO STRAIGHT TIP AFTER
. PART OF FIRST TEST AT
INLET SITE.
ORIFICE
THERMOMETERS
9£i
Jn
-"'i-iki
MANOMETER
MODIFIED
G-S IMPINGERS
CONTROL
VALVES
DRY TEST
METER
UMBILICAL
CORD
VACUUM
GAUGE
Figure 3. Fluoride and
sampling train
-------
containing 250 ml each of 2.5% sodium hydroxide , one empty
straight tip impinger, a 3" or 4" unheated Whatman #1 paper
filter, and an impinger containing approximately 200 grams of
accurately weighed silica gel. The impingers were contained
in an ice-water bath. A stainless steel nozzle and glass
lined probe were used in all cases. A flexible Teflon connector
(5' long) was used at both test sites to connect the probe to
the first impinger, as space limitations precluded the use of
a rigid train configuration.
After sampling,, the entire train was rinsed with distilled
water and combined with the impinger contents and the filter
into a single container. An acetone rinse of all components
was placed in a second container.
*2°5
A sampling train identical to that used for fluorides was
employed for the collection of P2°5 excePt that only 100 ml
of 2.5% sodium hydroxide was used in the first three impingers.
Sample recovery was identical to the fluoride procedure.
S00 and S00
"~ ' "^£ ""*" -" • • .3
Method 8 as described in the Federal Register was used
to measure sulfur oxides as shown in Figure 4. A rigid train
Though a 10% NaOH solution was originally planned, this was
changed to 2.5% based on tests conducted at another plant
during the previous week.
DFederal Register, Vol. 36, No. 247, December 23, 1971.
- 31 -
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t!
'
SS NOZZLE
HEATED GLASS PROBE
STACK WALL
u>
to
1
2
3
4
5
TO PUMP
AND METER
G-S IMPINGER - 100 ml
MODIFIED G-S IMPINGER
.G-S IMPINGER - 100 ml ,
MODIFIED G-S IMPINGER
FILTER HOLDER w/GLASS
80% ISOPROPANOL
- 100 ml. 3% H20Z
3% HzOZ
- 200 g., SILICA GEL
FIBER FILTER
Figure 4.
so2/so3
sampli ng trai n
-------
with heated glass lined probe was employed at both the inlet
and outlet of the venturi scrubber.
In all cases sampling was conducted under isokinetic
conditions by continually monitoring the velocity with a pitot
tube and adjusting the sampling rate accordingly. When slag
tapping and sampling stopped in the middle of a traverse, that
traverse point was completed at the start of the next slag tap
before going to the next traverse point.
i
Sample recovery consisted of rinsing the probe with
distilled water and adding the washings to the first impinger
along with the filter. The contents of the two impingers
after the filter were poured into another container and rinsed
with distilled water.
- 33 -
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