Mercury in Cement Clinker Production - Behaviour and Abatement of Emissions

Transcription

1 Mercury in Cement Clinker Production - Behaviour and Abatement of Emissions June 21 st, 2016 Reinhard Beilmann tkis Peru, 1 st Conference Determination and Abatement of Mercury Emissions

2 Behaviour of heavy Metals in Cement Kilns Arsenic Nickel Chrome Copper Cobalt Cadmium Lead Thallium Mercury Volatility non low light high Emissions 0 solid, (bounded) Enrichment on filter dust (%) bounded and gaseous 2 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

3 Concentration in mg/nm³ Mercury Emission Measurements at German Cement kilns 34 yearly averages from continuous control and 112 measurements from 44 plants. 5 Values below detection limit. Exceptional Limit: 50 μg/nm³ if caused by Raw Material Limit: 30 μg/nm³ Measurement Source: VDZ June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

4 Mercury Emission Measurements at US Cement kilns Source: 4 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

5 Mercury Cycle in Cement Kilns direct operation Hg-Sources: Fuels + Raw Meal Direct operation: High mercury emissions Adsorption on the dust (depends on the temperature) Mercury evaporation from Raw Meal Raw Meal Silo Filter Hg Hg Dust Fuels Silo Hg Clinker 5 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

6 Mercury Cycle in Cement Kilns compound operation Hg-Sources: Fuels/Raw Materials/Meal Compound operation: Enrichment in the outer cycle (depending on mill type, amount of kiln gas used for grinding) Raw Meal Silo Raw Materials Hg Lower mercury emissions Filter Hg Bypass Dust Fuels Silo Hg Clinker 6 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

7 Mercury - Typical Emission Behavior Source: tkis Stack Compound Operation Direct Operation Compound Operation 7 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

8 Primary Mercury Abatement Technologies Reduce Mercury input into the System Fuels: could be possible Raw Materials: might be possible if a minor component is the source but hardly achievable if the Limestone Quarry is the Source 8 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

9 Primary Mercury Abatement Technologies Dust shuttling (typically in direct operation) Exhaust gas cooling as a Precondition Mercury Removal in % Filter-dust to Clinker grinding or disposal Filter-dust back to process (Silo) Gas Temperature in C Quecksilberabscheidung in Abhängigkeit von der Gastemperatur 9 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

10 Hg concentration clean gas (µg/nm³) clean gas temperature ( C) Hg concentration clean gas (µg/nm³) clean gas temperature ( C) Primary Mercury Abatement Technologies Effect of Dust shuttling in direct operation Hg Emission without Dust Shuttling Hg Emission with Dust Shuttling in dircet operation Hg concentration clean gas clean gas temperature compound operation Hg concentration clean gas clean gas temperature compound operation Source: ZKG , June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

11 Secondary Mercury Abatement Technologies: ACI Dust Shuttling with ACI (typically in Direct Operation) Activated Carbon - Injection approx. Clinker 12-15kg AC/h Filter-dust to Clinker grinding or disposal approx. 10 t/h ; 0,15% Clinker and 8%Dust related to Clinker Filter-dust back to process (Silo) 11 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

12 Secondary Mercury Abatement Technologies: ACI Expected Hg-Removal with ACI from Industrial Trials (Landreth and Hardtke ZKG , 46-51) 1 lb/mmacf equal to approx. 16mg/Nm³ Removal efficiency generally confirmed by plant operations 12 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

13 Secondary Mercury Abatement Technology: ACI ACI with two Baghouses Activated Carbon - Injection improved efficiency pure activated carbon high investment landfill recycling Filter-dust back to process (Silo) 13 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

14 Secondary Mercury Abatement Technologies: ACI ACI - Hg-Removal Experience with two Baghouses Source: Mercury Reduction - The Plant Experience Terry Kerby, IEEE June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

15 Secondary Mercury Abatement Technology ACI with Hg-Desorption from Dust Activated Carbon - Injection Hg-Desorption Filter-dust back to process (Silo) 15 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

16 o o Secondary Mercury Abatement Technology - Thermal dust treatment for Hg-Desorption by TKIS Waste minimization: High Hg Enrichment factor Extremely compact design, mobile full scale demonstration plant possible Feed Cyclone ACF Clean Gas Reactor Product Heat Exchanger Product 16 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

17 Secondary Mercury Abatement Technology - Thermal dust treatment for Hg-Desorption by TKIS Indirectly heated Rotary kiln for thermal Treatment of EP-Dust Industrial Installation in June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

18 Mercury Online Measurement Big discussions about accuracy in cement process in Germany. Very low concentration (µg/nm³) Alternating concentrations Different measurement ranges in compound and direct operation Interferences (newer analyser with underground compensation) Hg HgCl 2 Only detection of elemental mercury (photometer) Ionic mercury hast to be converted to the elemental form Older analysers uses a converter material Deactivation by the sample gas of the kiln exhaust Newer analysers: Thermal conversation 18 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

19 Conclusion Mercury in Cement Kilns Mercury is completly volatile in the preheater During mill down times (direct operation), the outer cycle is partly unloaded Dust Shuttling is the first step to reduce Mercury Emission Low temperatures in the filter are advantageous Activated Carbon Injection may further reduce Emissions Plant specific emissions and the maximum allowable emission determine the suitable abatement technology 19 June 21st, 2016 Mercury in Cement Clinker Production Reinhard Beilmann tkis

20 Mercury in Cement Clinker Production Behaviour and Abatement Strategies Thank you for your attention! Any questions?