Mercury Abatement in the US Cement Industry

John Kline

John Kline Consulting

Cement Processing in US

82 Clinker Plants 128 Operating Kilns Source: EPA Web Site

Mercury Emissions in US by Source (metric tons per year)

Source Air Water Soil Mercury from cement production 2.31 0 1.16 Mercury from large combustion plants 43.46 0.17 33.06 TOTAL EMISSIONS (tpy) 109.2 46 2658.2 Cement as % of Total 2.1% 0% 0.04% Large Combustors as % of Total 39.8% 0.4% 1.2%

Source: The US Mercury Emission Inventory for the Arctic Council Action Plan, Karen Rackley and Anne Pope, 1999 National Emissions Inventory for HAPs (NEI) and 2001 Toxic Release Inventory (TRI).

Cement Kiln Regulations

All Cement Plants / Kilns

(NESHAP)

Commercial and Industrial Solid Waste Incinerators

(CISWI)

Hazardous Waste

Combustors (HWC)

Cement Plants that burn

Hazardous Waste

Cement Plants that burn Non-

Hazardous Waste

82 Clinker Plants 128 Operating Kilns

Summary of Standards

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%

Bold indicates a change

Monitoring Standards

Original Rule

• Particulate CEM

• Mercury CEM

• THC CEM

• HCl CEM

Final Rule

• Particulate Parametric Testing

• Mercury CEM

• THC CEM

Timing

• Original Compliance Date – Sept, 2013

• Revised Compliance Date – Sept, 2015

• Possibility of one year extension

– Need to demonstrate significant effort, and

– External forces at play

Mercury in Power Plants

• One source – Fuel

• Multiple Outlets – Bottom ash, slag, flyash, FGD solids, FGD liquids, stack

• One pass with no recycle

• Relatively stable gas composition and temperatures

• What goes in – comes out !

Mercury in Power Plants

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

Distribution of mercury concentrations in solid fuels from ICR, Part 2 data for fourth quarter, 1999. Source: Inherent Mercury Controls within the Portland Cement Kiln System—Model of Mercury Behavior within the Manufacturing System, C. Senior, C. Montgomery, A. Sarofim, Portland Cement Association

Mercury in Power Plants

• One source – Fuel => multiple fuel and raw material sources

• Multiple Outlets – Bottom ash, slag, flyash ash, FGD solids, FGD liquids, stack => outlets stack and dust

• One pass with no recycle => multiple potential recycle loops

• Relatively stable gas composition and temperatures => large swings in gas temperature and composition (with in-line mills)

Mercury in Cement Plants

Typical Levels of Mercury in the Cement Industry

Mercury concentration in PPB •Limestone 10 to 100, can be up to 1000 or more •Coal: 20 to 200 (also Cl = 800/2000ppm) •PRB: 40 to 100 (also Cl = 7/35ppm) •Coke: 10 to 20 •Other fuels: <50 •AF generally low – except HWF: up to 6000 (not in EPA) and SSW (up to 200)

•Bottom ash and fly ash: 200 to 400

Flyash – 37 Plants Bottom Ash – 21 Plants

Looking Deeper at Raw Materials

The most common ingredients of cement are: – Limestone (75% - 80%),

– Shale and/or clay (15% - 20%),

– Sand (2% – 5%),

– And Iron Source (1% - 2%)

Limestone, Shale and Clay are sedimentary materials and therefore typically low in metals including mercury

The exception comes when these materials are associated with volcanics

Variations in Raw Materials

Monthly mass balance Hg contributions by raw material (Linero, Read, and Derosa, 2008)

Mercury Cycle in a Modern Cement Plant with In-Line Raw Mill

Kiln Feed

Fuels From Kiln & Precalciner

Raw Mill Feed

BH Catch

Stack

Coal Mill

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

1000 oC

330 oC

90 oC

The Hg cycle / with in-line raw mill: can be 10 to 50 times the inputs

Source: “MERCURY IN THE CEMENT INDUSTRY”, Roberto RENZONI ,Christophe ULLRICH, Sandra BELBOOM, Albert GERMAIN, Universite de Liege, Independently commissioned by CEMBUREAU – CSI

Spot Balance in Preheater Kiln with Raw Mill Running

Spot Balance

Kiln

18-Jun-12 Filter Inlet Exit Gas Calculated

Feed In grams/hr Balance 18.8 PB 75.2 Ox.

369.1 PB Bypass grams/hr CEM Signal 174.4 Ox. 98.7 El.

83.9 Ox. % Capture 98.7 El. Fiter Capture 173.9 Total

30.0 El. 291.9 Total 57% Ox. Only Exit Gas Measured

113.9 Total 76.4 Ox.

100.3 El.

176.7 Total

Cylcone Out

18.8 PB

Fuel In Raw Mill Feed 90.5 Ox.

21.2 PB 293.4 PB 68.7 El.

178.0 Total

Raw Mill

Duct Capture

287.4 Ox. 53% Ox. Raw Mill Out CKD

102.8 El. 554.1 Total 118.0 PB

390.3 Total To Raw Mill

192.0 Ox.

68.7 El.

260.8 Total Raw Mill Product

376.1 PB Coke 0.13 PB Coal Mill

Coal 0.23 PB Exit Gas Calculated

0.16 El.

Exit Gas Measured

0.27 El.

To Coal Mill Coal Mill Product

11.5 Ox. 15.8 PB

4.1 El.

15.6 Total

Mercury Balance Mercury Inputs

From Kiln Feed 54.0%

From Fuel (As-Fried) 3.1%

From Raw Fuel 0.1%

From Raw Mill Feed 42.9%

Mercury Outputs

In Raw Mill Product 55.0%

In CKD 17.3%

Oxidized in Kiln Stack 11.0%

Elemental in Kiln Stack 14.4%

In Fine Coke 2.3%

in Coke Mill Stack 0.0%

All CKD Removed

The Hg cycle / with in-line raw mill: can be 10 to 50 times the inputs

Source: “MERCURY IN THE CEMENT INDUSTRY”, Roberto RENZONI ,Christophe ULLRICH, Sandra BELBOOM, Albert GERMAIN, Universite de Liege, Independently commissioned by CEMBUREAU – CSI

Schreiber & Kellett 2009

Mercury Emissions Raw Mill Off + Raw Mill On Scale Change

Influencing Factors Temperature Cl Available O Available SO3 Available

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

Schreiber & Kellett 2009

Mercury Emissions Averages All Cement Kilns Surveyed

Good Generalization but

each case is specific

Largest Emitters (2010 Data)

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Conclusions

• The mercury emission limit remains at 55 pounds per million tons of clinker

• Compliance has been pushed to September 2015, with the possibility of a one year extension

• More than half of the cement plants will have to reduce emissions to meet the new limit

• Roughly a third will have to install some form of control

• Many plants can qualify as CISWI installations which may not be coherent with NESHAP