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Gossman Consulting, Inc.

A Comparison of Normal and Worst Case Cement Plant Emissions

 

Jim Woodford
Gossman Consulting, Inc.
jimwoodf@gcisolutions.com
 
David Gossman
Gossman Consulting, Inc.
45W962 Plank Road
Hampshire, IL 60140
(847) 683-4188, Fax (847) 683-4212
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  
 
 
   
0.5174  
0.8623  
Silver 
0.0000  
0.0807  
0.0000  
0.0006 
0.0000  
0.0049  
0.0279  
0.0464 
0.0000  
0.0024  
 
 
   
0.0279  
0.1350  
Arsenic 
1.0412  
1.7354  
0.0258  
0.0431 
0.1178  
0.1964  
0.0264  
0.0441 
0.0000  
0.0012  
 
 
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  
 
 
   
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  
 
 
0.0510  
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  
 
 
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  
 
 
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  
 
 
   
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  
 
 
   
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  
 
 
   
0.8141  
1.3677  
Selenium 
0.0000  
0.0619  
0.0132  
0.0220 
0.0947  
0.1578  
0.0146  
0.0244 
0.0004  
0.0022  
 
 
   
0.1229  
0.2683  
Thallium 
6.0089  
10.0148  
0.0006  
0.0035 
0.0052  
0.0330  
0.0240  
0.0401 
0.0000  
0.0020  
 
 
   
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  
 
 
   
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  
 
 
   
0.4639 
0.7732  
Silver 
0.0000  
0.0748  
0.0000  
0.0008 
0.0000  
0.0040  
0.0131  
0.0218 
0.0000  
0.0025  
 
 
   
0.0131 
0.1038  
Arsenic 
0.8944  
1.4907  
0.0309  
0.0515 
0.1519  
0.2532  
0.0153  
0.0255 
0.0000  
0.0018  
 
 
 
 
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  
 
 
   
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  
 
 
 
 
0.1370 
0.2780  
Cadmium 
0.5259  
0.8765  
0.0032  
0.0054 
0.0181  
0.0301  
0.1117  
0.1862 
0.0000  
0.0001  
 
 
 
 
0.6589 
1.0982  
Chromium 
7.2634  
12.1056  
0.0819  
0.1365 
0.3990  
0.6650  
2.3423  
3.9038 
0.0000  
0.0006  
 
 
 
 
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  
 
 
   
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  
 
 
   
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  
 
 
   
0.2088 
0.5588  
Selenium 
0.0000  
0.0858  
0.0199  
0.0331 
0.0979  
0.1632  
0.0062  
0.0110 
0.0004  
0.0023  
 
 
   
0.1244 
0.2955  
Thallium 
8.3943  
13.9905  
0.0000  
0.0033 
0.0046  
0.0329  
0.0232  
0.0386 
0.0000  
0.0020  
 
 
   
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  

nvimage7

Figure 1. Metals and Chlorine Balance - Test Day 1 - 10/04/95
 

nvimage6

Figure 2. Metals Balance - Test Day 4 - 10/06/98

nvimage3

Figure 2. Input Range Comparison - Test Day 1 vs. Test Day 4

 
 

nvimage4

Figure 4. Emissions Comparison - Test Day 1 vs. Test Day 4

nvimage5

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.