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Published byKiley Motte Modified over 10 years ago
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Florida Department of Environmental Protection David Read Cement Subproject Manager Bureau of Air Regulation Cement Mercury Subproject
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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 American CEMEX N. Brooksville CEMEX S. Brooksville Titan America CEMEX Miami
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Fuel and Materials Hg – Plant A Concentrations in parts per billion (ppb)
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Fuel and Materials Hg – Plant A Contribution to total emissions in percent (%)
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EPA and Florida Kiln Emission Estimates in pounds (lb) of Hg per million tons of clinker Lowest ~ 10 lb/million tons clinker Highest ~ 3,300 lb/million tons clinker Best 12% by EPA ranking 40
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Raw Mill On – Most Hg Captured, Stored Coal Hg in (to Cement Mill) Meal & Hg Removed Hg in (from Raw Mix) Meal & Hg Stored RAW MEAL SILO (Hg) Filter Fuel Hg in Clinker No Hg out Hg out Little LOTS Raw Mill Off – Hg Emitted LEGEND Gas Solid Filter Dust Raw Mill Separators Preheater Exhaust Preheater Feed
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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 SO 2 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?)
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RAW MEAL SILO Hg out (to Cement Mill) Hg out Some Hg in (coal) No Hg out (to Cement Mill) Hg out Some Hg in (from Raw Mix) Hg in (fuel) Filter Scrubber (Hg Stored) (Hg Removed) Filter Dust Shuttling – Mill Off Problem Raw Material/Fuel Treatment Mercury Plant Hg in (Alternate Material/Fuel) Hg in Mercury Plant (Filter Dust) Hg (Filter Dust) Filter Dust Treatment, Return LEGEND Gas Solid Hg Removed by Scrubber Hg Removal by Activated Carbon Hg Removed Some Most Hg out Removed
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Comparison of Florida Kilns with Best 12% at 25, 50, and 75% reduction from present estimates
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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
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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
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