A Comparison of Normal and Worst Case Cement Plant Emissions
Gossman Consulting, Inc. David Gossman
Gossman Consulting, Inc.
dgossman@gcisolutions.com Norris Johnson
Lone Star Industries, Inc.
Presented at the AWMA International Specialty Conference on Waste Combustion in Boilers and Industrial Furnaces March, 1996
ABSTRACT
Lone Star Industries, Inc. in Cape Girardeau, Missouri conducted a
trial burn in October, 1995. Two metals emissions test days were
conducted. One of the test days was a worst case metals spiking day and
one of the test days was a normal emissions day. This paper examines
and compares the emissions from these two test days. Much has been made
of metals emissions from hazardous waste burning cement kilns, but for
the most part, this has been due to the worst case metals emissions
data that became available from the 1992 BIF compliance testing
performed and reported by 24 cement plants. By comparison, very little
data exists on normal cement kiln emissions. This paper provides one
comparison.
INTRODUCTION
The Lone Star Industries, Inc. (LSI) cement plant located in Cape
Girardeau, Missouri conducted a RCRA/BIF Trial Burn1 the
week of October 2, 1995. Two of the test days were metals emissions
stack testing days. The metals of concern were the ten BIF metals;
mercury, silver, arsenic, barium, beryllium, cadmium, chromium, lead,
antimony, and thallium plus nickel & selenium. One of those metals
test days involved the spiking and input of metals to the kiln under
the so called "worst case" scenario. Worst case being metals fed to the
kiln at rates sufficient to represent a maximum metals concentrations
input to the kiln and kiln temperatures being as hot as possible in
order to volatilize the most metals. These metals feed rates also
become the legal limit. A second metals test day, involving the same
twelve metals, was conducted under "normal" operating conditions.
Normal operations being representative of a typical cement
manufacturing day for the LSI Cape Girardeau preheater/precalciner
cement kiln. The prevailing logic for normal test day conditions was
that the worst case test conditions, required by BIF, were achieved for
approximately one week out of the year and that normal test day
conditions would be much more representative for purposes of risk
analysis. In this report, Test Day 1 data represents the worst case
scenario test day which also included metals spiking and Test Day 4
data represents the normal operations test day. The average operational
conditions for each test day are presented in Table 1.
TESTING
Metals stack testing was accomplished according to 40 CFR Part 266
Appendix IX; "Methodology for the Determination of Metals Emissions in
Exhaust Gases from Hazardous Waste Incineration and Similar Combustion
Processes,"2 also known as the BIF Method. Process sampling
was initiated at the beginning of each run and subsequent samples taken
once each hour thereafter. These hourly samples for each process stream
were later composited for each test run. Both process and stack samples
were analyzed for metals using atomic absorption spectroscopy (AAS)
inductively coupled argon plasma, graphite furnace or cold vapor AAS.
Feed rates of the various kiln feed streams inputs were coupled with
the metals concentrations of those feed streams to determine the metals
feed rates to the kiln for each test day. Those feed rates are
represented in Tables 2 and 3. A comparison of those feed rates is
graphically represented in Figure 3. A concerted effort was made to
input worst case arsenic, beryllium, cadmium, chromium and lead through
either spiking or elevating the metals concentrations in the waste fuel
that was fed to the kiln. Figure 3 illustrates the higher input level
on Test Day 1 as compared to Test Day 4 for each of these metals. Note
that when making range comparisons, only ranges that do not
significantly overlap should be considered different.
RESULTS
Using the kiln inputs and comparing them to the stack test results,
metals balances were determined for both test days as well. Those
balances are represented by Figures 1 and 2. It can be readily noted
that input/output balances are quite good for both days. The one
exception was mercury. The mercury inputs and outputs did not balance.
In the case of the Cape Girardeau preheater/precalciner cement kiln,
emissions are passed through the roller mill and appear to never reach
equilibrium. Some emissions have been demonstrated to increase without
the scrubbing/absorption action of the roller mill and to decrease with
the roller mill in operation.
Close examination of the metals emission rates for both the worst case day and the normal operations day reveal an interesting finding. The emission rates are very similar. These findings are represented in Table 4, and a comparison is graphically represented in Figure 4.
DISCUSSION
The most interesting finding that came out of the comparison between
the worst case data from Test Day 1 and the normal test day data from
Test Day 4 emerges when system removal efficiencies (SREs) are examined
for each metal under both test conditions. The data is presented in
Tables 2 and 3, and is graphically represented in Figure 5. Note that
SREs for arsenic and antimony are actually higher on the normal test
day rather than the hot kiln worst case test day as would be predicted
and/or is assumed by the boiler and industrial furnace regulations. In
addition, USEPA has provided recent communication that further
enunciates their BIF assumptions by stating that "Generally, SRE
decreases at lower feedrates."3 The normal test day SRE data
clearly conflicts with this assumption. The SRE comparison indicates
that there is no across the board volatility phenomena as is assumed by
the BIF testing requirements for a worst case scenario which includes a
hot kiln. While this data was collected on a preheater/precalciner kiln
and may only be specific to that type of kiln, it clearly raises a
number of questions. Do SREs vary in a similar fashion for other kilns?
Will SREs vary in a similar fashion for other preheater/precalciner
cement kilns? Will worst case metals emissions be similar to normal
operations metals emissions for other types of cement kilns? Will worst
case metals emissions be similar to normal operations metals emissions
for other preheater/precalciner kilns? Or, are the changes in SREs
reflective of normal background fluctuations in this type of testing
and none of the so-called worst case conditions are, in fact, worst
case?
Table 1. Operating Parameters.
| Stream |
Unit |
Test Day 1 |
Test Day 4 |
| HWF Total |
tons/hr |
10.2 |
8.46 |
| Kiln Feed |
tons/hr |
260 |
241 |
| Clinker |
tons/hr |
166 |
154 |
| Fourth Stage Gas Inlet Temperature |
Degrees, F |
1724 |
1669 |
| Main Baghouse Pressure Differential |
Inches, WC |
11.1 |
11.8 |
| Main Baghouse Inlet Temperature |
Degrees, F |
354 |
181 |
| Bypass Baghouse Pressure Differential |
Inches, WC |
8.4 |
10 |
| Bypass Baghouse Inlet Temperature |
Degrees, F |
440 |
420 |
Table 2. Metals and Chlorine Balance
Test Day 1 - 10/04/95
|
Kiln Feed lb/hr |
Coal Primary lb/hr |
Coal Precalciner lb/hr |
HFL lb/hr |
Tower Water lb/hr |
Tires lb/hr |
Spike lb/hr |
Total Input lb/hr |
||||||||||
|
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
||
|
Mercury
|
0.5024
|
0.8374
|
0.0005
|
0.0008
|
0.0031
|
0.0052
|
0.0113
|
0.0189
|
0.0000
|
0.0000
|
0
|
0
|
0.5174
|
0.8623
|
|||
|
Silver
|
0.0000
|
0.0807
|
0.0000
|
0.0006
|
0.0000
|
0.0049
|
0.0279
|
0.0464
|
0.0000
|
0.0024
|
0
|
0
|
0.0279
|
0.1350
|
|||
|
Arsenic
|
1.0412
|
1.7354
|
0.0258
|
0.0431
|
0.1178
|
0.1964
|
0.0264
|
0.0441
|
0.0000
|
0.0012
|
0
|
0
|
3.4038
|
4.1602
|
4.6151
|
6.1803
|
|
|
Barium
|
16.7713
|
27.9521
|
0.5647
|
0.9412
|
3.4350
|
5.7249
|
6.1229
|
10.2048
|
0.0001
|
0.0077
|
0
|
0
|
26.8939
|
44.8308
|
|||
|
Beryllium
|
0.1178
|
0.1963
|
0.0072
|
0.0120
|
0.0557
|
0.0929
|
0.0000
|
0.0051
|
0.0000
|
0.0026
|
0
|
0
|
0.0510
|
0.0624
|
0.2318
|
0.3713
|
|
|
Cadmium
|
0.2354
|
0.3923
|
0.0020
|
0.0034
|
0.0118
|
0.0197
|
0.2364
|
0.3939
|
0.0000
|
0.0026
|
0
|
0
|
4.1010
|
5.0124
|
4.5866
|
5.8242
|
|
|
Chromium
|
6.9968
|
11.6613
|
0.0629
|
0.1049
|
0.4350
|
0.7251
|
4.7272
|
7.8786
|
0.0000
|
0.0006
|
0
|
0
|
6.4665
|
7.9035
|
18.6887
|
28.2744
|
|
|
Nickel
|
5.5947
|
9.3246
|
0.0429
|
0.0714
|
0.3022
|
0.5036
|
0.4646
|
0.7743
|
0.0006
|
0.0077
|
0
|
0
|
6.4051
|
10.6818
|
|||
|
Lead
|
2.3027
|
3.8378
|
0.0464
|
0.0773
|
0.3246
|
0.5410
|
11.0538
|
18.4231
|
0.0000
|
0.0011
|
0
|
0
|
13.7276
|
22.8805
|
|||
|
Antimony
|
0.4038
|
0.6731
|
0.0000
|
0.0002
|
0.0000
|
0.0042
|
0.4095
|
0.6826
|
0.0007
|
0.0077
|
0
|
0
|
0.8141
|
1.3677
|
|||
|
Selenium
|
0.0000
|
0.0619
|
0.0132
|
0.0220
|
0.0947
|
0.1578
|
0.0146
|
0.0244
|
0.0004
|
0.0022
|
0
|
0
|
0.1229
|
0.2683
|
|||
|
Thallium
|
6.0089
|
10.0148
|
0.0006
|
0.0035
|
0.0052
|
0.0330
|
0.0240
|
0.0401
|
0.0000
|
0.0020
|
0
|
0
|
6.0388
|
10.0934
|
|||
|
Chlorine
|
103.7016
|
155.5523
|
2.613231
|
3.9198
|
8.4086
|
210.2148
|
460.7539
|
691.1309
|
1.3018
|
1.9527
|
0
|
0
|
576.7819
|
1062.841
|
|||
|
Kiln Dust Wasted lb/hr |
CKD Precalciner lb/hr |
Clinker lb/hr |
Worst Case Stack lb/hr |
System Removal Efficiency (%) |
Total Output lb/hr |
||||||||||||
|
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
||||||
|
Mercury
|
0.0000
|
0.0001
|
0.0795
|
0.1325
|
0.0085
|
0.0171
|
0.1784
|
0.2676
|
48.2774
|
79.3113
|
0.2665
|
0.4174
|
|||||
|
Silver
|
0.0354
|
0.0590
|
0.0065
|
0.0260
|
0.0000
|
0.0514
|
0.0001
|
0.0001
|
99.4789
|
99.9283
|
0.0420
|
0.1365
|
|||||
|
Arsenic
|
0.0749
|
0.1248
|
0.5418
|
0.9030
|
4.0550
|
6.7583
|
0.0004
|
0.0007
|
99.9858
|
99.9929
|
4.6721
|
7.7867
|
|||||
|
Barium
|
0.2926
|
0.4877
|
1.8704
|
3.1174
|
30.1475
|
50.2459
|
0.0022
|
0.0033
|
99.9878
|
99.9951
|
32.3128
|
53.8543
|
|||||
|
Beryllium
|
0.0024
|
0.0041
|
0.0155
|
0.0258
|
0.2219
|
0.3699
|
0.0000
|
0.0001
|
99.9686
|
99.9869
|
0.2399
|
0.3998
|
|||||
|
Cadmium
|
1.7446
|
2.9077
|
0.5637
|
0.9395
|
0.5637
|
0.9395
|
0.0013
|
0.0020
|
99.9560
|
99.9769
|
2.8734
|
4.7887
|
|||||
|
Chromium
|
0.1838
|
0.3064
|
0.6647
|
1.1079
|
15.1554
|
25.2590
|
0.0012
|
0.0019
|
99.9900
|
99.9956
|
16.0052
|
26.6751
|
|||||
|
Nickel
|
0.0672
|
0.1120
|
0.4570
|
0.7616
|
6.4004
|
10.6673
|
0.0010
|
0.0015
|
99.9760
|
99.9904
|
6.9255
|
11.5424
|
|||||
|
Lead
|
4.8750
|
8.1250
|
2.2609
|
3.7681
|
4.6821
|
7.8036
|
0.0048
|
0.0072
|
99.9478
|
99.9791
|
11.8228
|
19.7038
|
|||||
|
Antimony
|
0.0200
|
0.0334
|
0.0090
|
0.0296
|
1.2201
|
2.0335
|
0.0004
|
0.0006
|
99.9312
|
99.9727
|
1.2495
|
2.0970
|
|||||
|
Selenium
|
0.0919
|
0.1532
|
0.0293
|
0.0488
|
0.0000
|
0.0983
|
0.0044
|
0.0066
|
94.6103
|
98.3542
|
0.1256
|
0.3070
|
|||||
|
Thallium
|
0.0150
|
0.0250
|
6.0883
|
10.1472
|
0.0000
|
0.1280
|
0.0059
|
0.0089
|
99.8533
|
99.9415
|
6.1092
|
10.3091
|
|||||
|
Chlorine
|
449.8347
|
674.752
|
87.77449
|
131.6617
|
41.3655
|
62.04826
|
71.068
|
86.86089
|
650.0427
|
955.3229
|
|||||||
|
HCl
|
70.1
|
85.67778
|
85.1455
|
93.4045
|
|||||||||||||
|
Cl2
|
0.968
|
1.183111
|
99.7949
|
99.9089
|
|||||||||||||
Table 3. Metals Balance
Test Day 4 - 10/06/95
|
Kiln Feed lb/hr |
Coal Primary lb/hr |
Coal Precalciner lb/hr |
HFL Lb/hr |
Tower Water lb/hr |
Tires lb/hr |
Spike lb/hr |
Total Input lb/hr |
|||||||||
|
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
|
|
Mercury
|
0.4577
|
0.7628
|
0.0004
|
0.0007
|
0.0022
|
0.0037
|
0.0037
|
0.0061
|
0.0000
|
0.0000
|
0
|
0
|
0.4639
|
0.7732
|
||
|
Silver
|
0.0000
|
0.0748
|
0.0000
|
0.0008
|
0.0000
|
0.0040
|
0.0131
|
0.0218
|
0.0000
|
0.0025
|
0
|
0
|
0.0131
|
0.1038
|
||
|
Arsenic
|
0.8944
|
1.4907
|
0.0309
|
0.0515
|
0.1519
|
0.2532
|
0.0153
|
0.0255
|
0.0000
|
0.0018
|
0
|
0
|
0
|
0
|
1.0926
|
1.8228
|
|
Barium
|
13.3076
|
22.1793
|
0.5411
|
0.9019
|
3.3526
|
5.5876
|
4.7901
|
7.9834
|
0.0001
|
0.0079
|
0
|
0
|
21.9914
|
36.6601
|
||
|
Beryllium
|
0.0652
|
0.1500
|
0.0114
|
0.0190
|
0.0605
|
0.1008
|
0.0000
|
0.0042
|
0.0000
|
0.0040
|
0
|
0
|
0
|
0
|
0.1370
|
0.2780
|
|
Cadmium
|
0.5259
|
0.8765
|
0.0032
|
0.0054
|
0.0181
|
0.0301
|
0.1117
|
0.1862
|
0.0000
|
0.0001
|
0
|
0
|
0
|
0
|
0.6589
|
1.0982
|
|
Chromium
|
7.2634
|
12.1056
|
0.0819
|
0.1365
|
0.3990
|
0.6650
|
2.3423
|
3.9038
|
0.0000
|
0.0006
|
0
|
0
|
0
|
0
|
10.0869
|
16.8120
|
|
Nickel
|
4.8535
|
8.0892
|
0.0751
|
0.1252
|
0.3752
|
0.6253
|
0.2997
|
0.4996
|
0.0006
|
0.0079
|
0
|
0
|
5.6043
|
9.3474
|
||
|
Lead
|
2.7765
|
4.6276
|
0.0936
|
0.1561
|
0.4162
|
0.6937
|
5.0452
|
8.4086
|
0.0003
|
0.0021
|
0
|
0
|
8.3320
|
13.8883
|
||
|
Antimony
|
0.0230
|
0.2405
|
0.0000
|
0.0003
|
0.0000
|
0.0036
|
0.1853
|
0.3088
|
0.0005
|
0.0056
|
0
|
0
|
0.2088
|
0.5588
|
||
|
Selenium
|
0.0000
|
0.0858
|
0.0199
|
0.0331
|
0.0979
|
0.1632
|
0.0062
|
0.0110
|
0.0004
|
0.0023
|
0
|
0
|
0.1244
|
0.2955
|
||
|
Thallium
|
8.3943
|
13.9905
|
0.0000
|
0.0033
|
0.0046
|
0.0329
|
0.0232
|
0.0386
|
0.0000
|
0.0020
|
0
|
0
|
8.4221
|
14.0674
|
||
|
Chlorine
|
166.8629
|
250.2944
|
5.482217
|
8.223326
|
6.224397
|
155.4462
|
212.0356
|
318.0534
|
1.3747
|
2.06209
|
0
|
0
|
391.9807
|
734.1014
|
||
|
Kiln Dust Wasted lb/hr |
CKD Precalciner lb/hr |
Clinker lb/hr |
Worst Case Stack lb/hr |
System Removal Efficiency (%) |
Total Output lb/hr |
|||||||||||
|
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
min |
max |
|||||
|
Mercury
|
0.0002
|
0.0005
|
0.1323
|
0.2205
|
0.0057
|
0.0082
|
0.0398
|
0.0598
|
87.1189
|
94.8476
|
0.1781
|
0.2890
|
||||
|
Silver
|
0.0219
|
0.0366
|
0.0060
|
0.0241
|
0.0000
|
0.0475
|
0.0015
|
0.0022
|
83.1239
|
98.5818
|
0.0294
|
0.1103
|
||||
|
Arsenic
|
0.0212
|
0.0353
|
0.1122
|
0.1871
|
1.0409
|
1.7349
|
0.0004
|
0.0006
|
99.9476
|
99.9791
|
1.1747
|
1.9578
|
||||
|
Barium
|
0.2566
|
0.4277
|
1.6531
|
2.7552
|
19.9467
|
33.2446
|
0.0003
|
0.0005
|
99.9977
|
99.9991
|
21.8568
|
36.4280
|
||||
|
Beryllium
|
0.0019
|
0.0031
|
0.0135
|
0.0225
|
0.1311
|
0.2185
|
0.0001
|
0.0001
|
99.9421
|
99.9810
|
0.1465
|
0.2442
|
||||
|
Cadmium
|
0.3150
|
0.5250
|
0.1265
|
0.2108
|
0.2602
|
0.4337
|
0.0001
|
0.0001
|
99.9789
|
99.9916
|
0.7018
|
1.1696
|
||||
|
Chromium
|
0.1073
|
0.1788
|
0.6777
|
1.1294
|
8.3889
|
13.9815
|
0.0003
|
0.0005
|
99.9950
|
99.9980
|
9.1742
|
15.2902
|
||||
|
Nickel
|
0.0589
|
0.0982
|
0.4493
|
0.7489
|
4.7389
|
7.8982
|
0.0002
|
0.0002
|
99.9957
|
99.9983
|
5.2473
|
8.7455
|
||||
|
Lead
|
2.3660
|
3.9433
|
1.2715
|
2.1191
|
1.8106
|
3.0177
|
0.0022
|
0.0033
|
99.9607
|
99.9843
|
5.4503
|
9.0835
|
||||
|
Antimony
|
0.0104
|
0.0173
|
0.0023
|
0.0241
|
0.3252
|
0.5420
|
0.0004
|
0.0006
|
99.7057
|
99.9267
|
0.3383
|
0.5840
|
||||
|
Selenium
|
0.0950
|
0.1584
|
0.0023
|
0.0096
|
0.0000
|
0.0908
|
0.0025
|
0.0038
|
96.9321
|
99.1391
|
0.0999
|
0.2625
|
||||
|
Thallium
|
0.0155
|
0.0258
|
5.8795
|
9.7992
|
0.0000
|
0.1314
|
0.0005
|
0.0007
|
99.9918
|
99.9967
|
5.8955
|
9.9572
|
||||
|
Chlorine
|
349.9947
|
524.992
|
90.5097
|
135.7645
|
5.09437
|
7.64155
|
445.5987
|
668.3981
|
||||||||
Table 4. Stack Emissions Summary
Concentrations (F g/dscm @ 7%O2)
|
Test Day 1 10-04-95 |
Run 1 |
Run 2 |
Run 3 |
Avg |
Min |
Max |
| Mercury |
300
|
293
|
303
|
298.67
|
293
|
303
|
| Silver |
<0.163
|
<0.166
|
<0.188
|
<0.17
|
<0.163
|
<0.188
|
| Arsenic |
0.732
|
0.388
|
0.846
|
0.66
|
0.388
|
0.846
|
| Barium |
3.68
|
2.69
|
2.58
|
2.98
|
2.58
|
3.68
|
| Beryllium |
<0.0814
|
<0.0828
|
<0.0939
|
<0.09
|
<0.0814
|
<0.0939
|
| Cadmium |
2.25
|
0.856
|
0.706
|
1.27
|
0.706
|
2.25
|
| Chromium |
2.09
|
1.18
|
1.27
|
1.51
|
1.18
|
2.09
|
| Nickel |
1.63
|
1.08
|
2.02
|
1.58
|
1.08
|
2.02
|
| Lead |
8.02
|
3.38
|
2.85
|
4.75
|
2.85
|
8.02
|
| Antimony |
0.627
|
0.481
|
0.687
|
0.60
|
0.481
|
0.687
|
| Selenium |
5.11
|
5.89
|
8.72
|
6.57
|
5.11
|
8.72
|
| Thallium |
9.92
|
8.86
|
10.7
|
9.83
|
8.86
|
10.7
|
| Test
Day 4 10-06-95 |
Run 1 |
Run 2 |
Run 3 |
Avg |
Min |
Max |
| Mercury |
69.7
|
40.4
|
19.9
|
43.3333
|
19.9
|
69.7
|
| Silver |
<0.185
|
2.78
|
<0.165
|
<1.04333
|
<0.165
|
<2.78
|
| Arsenic |
0.661
|
0.434
|
0.636
|
0.577
|
0.434
|
0.661
|
| Barium |
0.35
|
0.642
|
0.433
|
0.475
|
0.35
|
0.642 |
| Beryllium |
<0.0925
|
<0.0983
|
<0.0824
|
<0.09106
|
<0.0824
|
<0.0983
|
| Cadmium |
0.146
|
0.067
|
0.155
|
0.12266
|
0.067
|
0.155
|
| Chromium |
0.468
|
0.642
|
0.49
|
0.53333
|
0.468
|
0.642
|
| Nickel |
0.145
|
0.0625
|
0.269
|
0.15883
|
0.0625
|
0.269
|
| Lead |
3.83
|
0.418
|
<0.165
|
<1.471
|
<0.165
|
<3.83
|
| Antimony |
<0.277
|
0.384
|
0.683
|
<0.448
|
<0.277
|
<0.683
|
| Selenium |
1.9
|
3.06
|
4.24
|
3.06666
|
1.9
|
4.24
|
| Thallium |
0.758
|
0.875
|
0.551
|
0.728
|
0.551
|
0.875
|
Figure 1. Metals and Chlorine Balance - Test Day 1 - 10/04/95
Figure 2. Metals Balance - Test Day 4 - 10/06/98
Figure 2. Input Range Comparison - Test Day 1 vs. Test Day 4
Figure 4. Emissions Comparison - Test Day 1 vs. Test Day 4
Figure 5. SRE Comparison - Test Day 1 vs. Test Day 4
REFERENCES
1. Lone Star Industries, Inc., Cape Girardeau, MO, Trial Burn Report, December, 1995.
2. United States Environmental Protection Agency, Burning of Hazardous Waste in Boilers and Industrial Furnaces, 40 CFR Part 266, Government Printing Office (NTIS), 1990.
3. M. Shapiro, Director-Office of Solid Waste, USEPA, Washington,
DC, personal communication, 1995.