1. John Kline – John Kline Consulting
Robert Schreiber Jr. – Schreiber, Yonley & Associates
April 2013

2. Presentation
 Background
 Sources of Mercury
 Mercury Oxidation
 Typical Emissions
 Internal Cycles
 Mass Balances
 Conclusions

3. NESHAP Rules Reissued
Pollutant Existing Sources New Sources EPA expected
Emissions
Reductions
Mercury 55 lb/million tons
clinker
21 lbs/million tons
clinker
93%
THC 24 ppmvd 24 ppmvd 82%
O-HAP 12 ppmvd 12 ppmvd
PM 0.07 lb/ton clinker 0.02 lb/ton clinker 91%
HCL 3 ppmvd 3 ppmvd 96%
Compliance Date September 2015

4. Knowledge comes from coal
And Slag
Input
Outputs
Output
Source - Tutorial: Mercury Chemistry in Boilers and Mercury Control Technology (Part 1), C. Senior, April
17-21, 2005 30th International Technical Conference on Coal Utilization & Fuel Systems, Clearwater,
Florida

5. But, Cement is Very Different
Source: "Fate and transport of mercury in Portland cement manufacturing facilities", J.K. Sikkema. Theses and Dissertations. Paper 11907. http://lib.dr.iastate.edu/etd/11907
Kiln Feed
Fuels From
Kiln &
Precalciner
Raw Mill
BH Catch
Stack
Coal
Mill
1000 oC
330 oC
90 oC

6. Fuel Sources
Mean Values 0.035 – 0.095

7. Raw Materials
0.001
0.01
0.1
1
Limestone Clay Shale Sand Flyash Bottom
Ash
Mill Scale
MercuryConcentrationsinPPM
Min
Max
Mean

8. And materials can vary over time
Monthly mass balance Hg contributions by raw material (Linero, Read, and Derosa, 2008)

9. Mercury oxidation occurs
Influencing
Factors
Temperature
Cl Available
O Available
SO3 Available

10. Typical Cement Kiln Emissions

11. Schreiber & Kellett 2009
Mercury Speciation – Long Wet

12. Mercury Speciation – Long Dry
Schreiber & Kellett 2009

13. Good
Generalization
but each case is
specific
Mercury Speciation – Summary
Schreiber & Kellett 2009

14. Internal Cycles
 Raw mill
 Can capture 90% of mercury emissions
 Captured mercury tends to be oxidized
 Coal mill
 Captures mercury if using preheater gases
 Complete internal cycle until disruption
 Baghouse
 Can capture a large amount of mercury
 Dust removal can be effective bleed

15. Large internal cycles
Mercury in the Cement Industry, commissioned by Cembureau – CSI (April 2010)
Raw
Meal
BH
Dust

16. Scale
Change
Mercury Emissions Mill On / Off
Schreiber & Kellett 2009

17. Mass Balances
 Periodic / Average value mass balances
 Give a good overall picture
 Can take into effect longer term variations in
fuels and raw materials
 Spot Balances
 Give a view of what is happening at the
moment
 Allows identification of internal cycles

18. Annual Mass Balance
Tons/hr PPM Hg Lbs Hg/hr
Limestone 136 1.02 0.292
Shale 20 0.01 0.037
Clay 16 0.23 0.008
Iron 5 0.00 0.000
Total Feed 174 0.90 0.3370.000
Fuel 13 0.02 0.0010.000
Total Input 0.338
Clinker 117 0.02 0.005
Hours ug Hg/DSCM Lbs Hg/hr
Mill On 6,245 241 0.094
Mill Off 1,207 2197 0.162
Stack Total 0.2560.000
Total Output 0.260
Balance 77%

19. Mercury Cycles
0%
100%
200%
300%
400%
500%
600%
700%
800%
900%
1000%
Raw Coal As Fired
Fuel
Raw Mill
Feed
Kiln Feed Preheater
Exit
Raw Mill
Product
CKD Stack
Plant A Mill On
Plant A Mill Off
Plant B Mill On
Plant C Mill On
Plant D Mill On
Plant E Averaged

20. Spot Balance
Particle Gaseous
DRY TPH ppm lbs/hr Bound lbs/h lbs/hr
Inputs
Kiln Feed 122.4 3.016 0.813 0.813
Mix fuel (as fired) 6.8 2.996 0.045 0.045
Tires (as fired) 0.4 0.168 0.000 0.000
CFS (as fired) 1.4 0.586 0.002 0.002
Coarse coke 0.000 0.000
Coal fines 0.001 0.001
Raw Mill Feed Rate 121.0 2.425 0.646 0.646
Total In 0.646 0.860
Outputs
Raw Mill Product 119.6 3.145 0.828 0.828
Out of Filter in CKD 8.4 13.988 0.260 0.260
Stack Oxidized 0.166
Stack Elemental 0.217
Coke Mill Product 9.4 1.676 0.035 0.035
Coke Mill Stack 0.000
Total Out 1.123 0.383

21. Spot Balance
Calculated Measured
ug/DNCM ug/DNCM
Oxidized Hg+ 394 400
Elemental Hg0 517 525
Total HgT 911 925
Balance 98%
53% Oxidized captured in raw mill from kiln gas
57% Oxidized captured in Filter
98% Oxidized & elemental captured in coal mill

22. Spot Balance
OutputsInputs
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
1400.0
1600.0
8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00
Fuel KilnFeed Mill Feed Mill Product CKD Stack
Raw Mill
Feeder Choke
0.0
100.0
200.0
300.0
400.0
500.0
600.0
700.0
800.0
900.0
In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out In Out
8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00
Spot Balance

23. Conclusions
 Cement plants are more complex and
more variable than power plants
 Mercury input varies according to the
raw materials and fuels used
 Mercury levels vary even within a
specific raw material or fuel over time
 Mercury oxidation is important to control
strategies and needs to be better
understood

24. Conclusions
 Modern cement plants have up to 3
internal cycles
 In-line raw mills
 Fuel processing using preheater gases
 Return dust from exhaust gas filters
 Global and spot balances should be
performed over several time periods to
better understand the mercury cycles
 Do not purchase your abatement
technology until you understand your
cycles