florida department of environmental protection david read cement subproject manager bureau of air...
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Florida Department of Environmental Protection
David Read
Cement Subproject ManagerBureau of Air Regulation
Cement Mercury Subproject
Florida Cement Industry
• 10,000,000 tons per year clinker
• Ten cement kilns
• Demand is down
• Five in operation
• Two are temporarily down
• Three at/near startup
Suwannee American
Vulcan
AmericanCEMEX N. Brooksville
CEMEX S. Brooksville
Titan America
CEMEX Miami
Fuel and Materials Hg – Plant AConcentrations in parts per billion (ppb)
0
50
100
150
200
250
300
Pa
rts
pe
r b
illi
on
(p
pb
)
Limestone Sand Iron Ore Fly Ash HC fly Ash Coal
Other
Coal Ash
Fuel and Materials Hg – Plant AContribution to total emissions in percent (%)
44.02
42.16
10.26
3.56
Limestone Coal Ash Coal Other
EPA and Florida Kiln Emission Estimatesin pounds (lb) of Hg per million tons of clinker
10
100
1000
10000
0 10 20 30 40 50 60 70 80 90 100
Kiln Number
U.S. Kilns FL Kilns (Mass Balance) New FL Kilns (Potential) FL Kilns (DEP Estimate)
Lowest ~ 10 lb/million tons clinker
Highest ~ 3,300 lb/million tons clinker
Best 12% by EPA ranking
40
Raw Mill On – Most Hg Captured, Stored
CoalHg in
(to Cement Mill)
Meal & Hg Removed
Hg in(from Raw Mix)
Meal & Hg Stored
RAW
MEAL
SILO
(Hg)
Filter
FuelHg in
ClinkerNo Hg out
Hg outLittleLOTSRaw Mill Off – Hg Emitted
LEGEND
GasSolid
Filter Dust
Raw Mill
Separators
Preheater Exhaust
Preheater Feed
Hg Control Options
• Limit high carbon coal ash, raw materials/fuels Hg• Add-on control equipment prior to stack
Baghouse, activated carbon (Norcem Brevik and Ash Grove Durkee, Oregon) Wet Scrubber (such as for SO2 in TXI Midlothian, Holcim Holly Hill)
• Heat and return filter dust, recover Hg in activated carbon Much smaller gas volume than end-of-process controls (F.L. Smidth offers)
• Heat problem fuels/material, recover Hg in activated carbon Also much smaller volume (F.L. Smidth describes in patent)
• Filter dust shuttling to cement product Typically practiced in some European countries (allowed in Florida?)
RAW
MEAL
SILO
Hg out(to Cement Mill)
Hg out Some
Hg in(coal)
No Hg out(to Cement Mill)
Hg outSome
Hg in(from Raw Mix)
Hg in(fuel)
Filter
Scrubber
(Hg Stored)(Hg Removed)
Filter Dust Shuttling – Mill OffProblem Raw Material/Fuel Treatment
MercuryPlant
Hg in(Alternate
Material/Fuel)
Hg in
Mercury Plant
(Filter Dust)
Hg
(Filter Dust)
Filter Dust Treatment, Return
LEGEND
GasSolid
Hg Removed by ScrubberHg Removal by Activated Carbon
Hg Removed
Some
Most
Hg out
Removed
Comparison of Florida Kilns with Best 12%
at 25, 50, and 75% reduction from present estimates
10
100
1000
10000
0 10 20 30 40 50 60 70 80 90 100
Kiln Number
U.S. Kilns Florida Kilns FL 75% Reduction FL 50% Reduction FL 25% Reduction
40
Florida Cement Industry Summary
• Florida kilns emit ~ 100 lb Hg/million tons clinker
• At full capacity emissions will be ~ 1,000 lb Hg/year
• A well-controlled coal power unit emits < 20 lb Hg/year
• EPA will propose draft limit by March 31, 2009
• May need significant reductions to achieve EPA limit
• Start with more careful materials and fuel selection
• Avoid high carbon fly ash (abated power plant emissions)
• Shuttle filter dust to product to extent cement meets specs
• Treat problem alternative fuels/materials
• Only then get to end-of-process add-on controls
Additional Thoughts• Need better data at some existing kilns• Material testing, sorbent traps, Hg-CEMS• Total Maximum Daily Load (TMDL) driver• May require limits beyond EPA MACT*• We ought to try out dust shuttling first• We will visit FDOT** to see if allowed
* Maximum Achievable Control Technology
** Florida Department of Transportation