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Tekran ® Automated Mercury Speciation F.H. Schaedlich 1, Robert K. Stevens 2, D.R. Schneeberger 2, Eric Prestbo 3, Steve Lindberg 4, Gerald Keeler 5 F.H.

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Presentation on theme: "Tekran ® Automated Mercury Speciation F.H. Schaedlich 1, Robert K. Stevens 2, D.R. Schneeberger 2, Eric Prestbo 3, Steve Lindberg 4, Gerald Keeler 5 F.H."— Presentation transcript:

1 Tekran ® Automated Mercury Speciation F.H. Schaedlich 1, Robert K. Stevens 2, D.R. Schneeberger 2, Eric Prestbo 3, Steve Lindberg 4, Gerald Keeler 5 F.H. Schaedlich 1, Robert K. Stevens 2, D.R. Schneeberger 2, Eric Prestbo 3, Steve Lindberg 4, Gerald Keeler 5 1 Tekran Inc., Railside Rd. Toronto, Canada M3A 1A3, 2 Florida Dept. Environmental Protection at USEPA, Res Triangle Park, NC 27711, 3 Frontier Geosciences Inc., 414 Pontius Ave. N., Suite B, Seattle, WA Oak Ridge National Lab. PO Box 2008, Oak Ridge, TN University of Michigan, School of Public Health, 109 Observatory Street, MI

2 Tekran Automated Mercury Speciation Objectives Development of automated methods to measure and differentiate between: Development of automated methods to measure and differentiate between: Reactive Gaseous Mercury (RGM) in ambient air Reactive Gaseous Mercury (RGM) in ambient air Total Particulate Mercury (TPM) in ambient air Total Particulate Mercury (TPM) in ambient air Elemental mercury (Hg 0 ) in ambient air Elemental mercury (Hg 0 ) in ambient air

3 Tekran Automated Mercury Speciation Ambient Air Mercury Speciation Different forms of gaseous Hg have very different behaviors. Different forms of gaseous Hg have very different behaviors. Forms can interconvert in the atmosphere and in various reservoirs. Forms can interconvert in the atmosphere and in various reservoirs. Classes of mercury in ambient air: Classes of mercury in ambient air: Elemental mercury: Hg 0. Elemental mercury: Hg 0. Reactive mercury: Hg II, RGM, Hg 2+. Reactive mercury: Hg II, RGM, Hg 2+. Particulate mercury: Hg P, TPM. Particulate mercury: Hg P, TPM.

4 Tekran Automated Mercury Speciation Model 2537A Mercury Analyzer Provides continuous total gaseous (TGM) readings with update rate as low as 2.5 minutes. Provides continuous total gaseous (TGM) readings with update rate as low as 2.5 minutes. Detection limit < 0.1 ng/m 3 (5 min. samples). Detection limit < 0.1 ng/m 3 (5 min. samples). Automatic recalibration with internal Hg 0 permeation source. Automatic recalibration with internal Hg 0 permeation source. Capable of unattended operation for extended periods. Capable of unattended operation for extended periods.

5 Tekran Automated Mercury Speciation Model 2537A Analyzer

6 Tekran Automated Mercury Speciation Flow Diagram of Model 2537A Mercury Analyzer

7 Tekran Automated Mercury Speciation Elemental Mercury: Hg 0 Typically 90+% of atmospheric Hg loadings. Typically 90+% of atmospheric Hg loadings. Relatively inert. Long residence time. Relatively inert. Long residence time. Hg 0 sources impact large areas. Hg 0 sources impact large areas. Sources: chlor-alkali plants, gold and Hg mining, thermal power plants. Sources: chlor-alkali plants, gold and Hg mining, thermal power plants.

8 Part 1 Reactive Gaseous Mercury Monitoring

9 Tekran Automated Mercury Speciation Why Bother Measuring RGM ? RGM (as HgCl 2 ) is emitted from power plants and incinerators. RGM (as HgCl 2 ) is emitted from power plants and incinerators. RGM is removed rapidly via wet and dry deposition. RGM is removed rapidly via wet and dry deposition. Often responsible for contamination of sensitive nearby ecosystems. (Florida Everglades, Arctic). Often responsible for contamination of sensitive nearby ecosystems. (Florida Everglades, Arctic).

10 Tekran Automated Mercury Speciation Reactive Mercury: Hg(II) or RGM Consists of reactive, water soluble forms, primarily HgCl 2. Consists of reactive, water soluble forms, primarily HgCl 2. Usually only a few percent of total gaseous mercury present in the atmosphere. Usually only a few percent of total gaseous mercury present in the atmosphere. Short range: deposits relatively close to the source of emission. Short range: deposits relatively close to the source of emission. Primary sources: Coal burning power plants, waste incinerators. ( Chlor-alkali plants ?) Primary sources: Coal burning power plants, waste incinerators. ( Chlor-alkali plants ?)

11 Tekran Automated Mercury Speciation Difficulties Measuring RGM Method must be 1-2 orders of magnitude more sensitive than total mercury methods. Method must be 1-2 orders of magnitude more sensitive than total mercury methods. Reject much larger elemental component. Reject much larger elemental component. Exclude particulate bound mercury, however, particulate filters have problems passing RGM. Exclude particulate bound mercury, however, particulate filters have problems passing RGM. Apparatus must pass RGM to the collector quantitatively. Apparatus must pass RGM to the collector quantitatively.

12 Tekran Automated Mercury Speciation Model Principles of Operation Quartz, specially coated annular denuder is thermally desorbed and regenerated. Quartz, specially coated annular denuder is thermally desorbed and regenerated. Sampling Phase. Sampling Phase. Absorbs RGM while passing all elemental Hg. Absorbs RGM while passing all elemental Hg. Model 2537A reads Hg 0 during this phase. Model 2537A reads Hg 0 during this phase. Desorption/Analysis Phase. Desorption/Analysis Phase. Zero air used as carrier. Zero air used as carrier. RGM released as elemental mercury. RGM released as elemental mercury.

13 Tekran Automated Mercury Speciation RGM Sampling Phase Denuder is slightly warm. Denuder is slightly warm. Inlet slightly warm. Inlet slightly warm. Denuder captures all RGM while passing Hg 0. Denuder captures all RGM while passing Hg 0. Total sample flow is 10 lpm. Total sample flow is 10 lpm. Analyzer measures Hg 0 during this time. Analyzer measures Hg 0 during this time.

14 Tekran Automated Mercury Speciation Analysis Phase Denuder is heated to 500C. Denuder is heated to 500  C. Inlet heated to clean upstream glassware. Inlet heated to clean upstream glassware. Denuder releases captured RGM as Hg 0. Denuder releases captured RGM as Hg 0. Excess zero air flow cleans upstream components. Excess zero air flow cleans upstream components. Instrument measures accumulated RGM as Hg 0. Instrument measures accumulated RGM as Hg 0.

15 Tekran Automated Mercury Speciation Lab RGM Apparatus

16 Tekran Automated Mercury Speciation Quartz Denuder Assembly

17 Tekran Automated Mercury Speciation Model 1130 Denuder & Pump Module

18 Tekran Automated Mercury Speciation Preliminary Results - Toronto

19 Tekran Automated Mercury Speciation Preliminary Results - Toronto

20 Tekran Automated Mercury Speciation Lab Testing: Frontier Geosciences

21 Tekran Automated Mercury Speciation Seattle RGM Data Ambient Air - Downtown Seattle Courtesy: Frontier Geosciences

22 Tekran Automated Mercury Speciation Mercury Levels - Rural Michigan Courtesy: UMAQL

23 Tekran Automated Mercury Speciation Summary - RGM A quartz annular denuder coated with KCl quantitatively collects HgCl 2 but does not retain Hg 0. A quartz annular denuder coated with KCl quantitatively collects HgCl 2 but does not retain Hg 0. HgCl 2 collected on a denuder is thermally desorbed as Hg 0. HgCl 2 collected on a denuder is thermally desorbed as Hg 0. The automated instrument that uses this denuder technology measures RGM concentrations down to 1 pg/m 3. The automated instrument that uses this denuder technology measures RGM concentrations down to 1 pg/m 3. Denuder lasts weeks between recoatings. Denuder lasts weeks between recoatings.

24 Part 2: Particulate Mercury Monitoring

25 Tekran Automated Mercury Speciation Why Bother Measuring TPM ? Particulate bound mercury (TPM / Hg P ) is created directly by some industrial processes and also formed downwind of sources by the combination of mercury with existing particulates. Particulate bound mercury (TPM / Hg P ) is created directly by some industrial processes and also formed downwind of sources by the combination of mercury with existing particulates. TPM is removed rapidly via wet and dry deposition. TPM is removed rapidly via wet and dry deposition.

26 Tekran Automated Mercury Speciation Particulate Mercury: TPM Consists of various compounds of mercury bound onto particles. Consists of various compounds of mercury bound onto particles. Size range: Generally < 3 um. Size range: Generally < 3 um. Usually only a few percent of total mercury present in the atmosphere. Usually only a few percent of total mercury present in the atmosphere. Short range: deposits relatively close to the source of emission. Short range: deposits relatively close to the source of emission.

27 Tekran Automated Mercury Speciation Difficulties Measuring TPM Method must be 1-2 orders of magnitude more sensitive than total mercury methods. Method must be 1-2 orders of magnitude more sensitive than total mercury methods. Must reject much larger elemental component. Must reject much larger elemental component. Method must exclude reactive gaseous mercury, however, normal particulate filters have problems in that they retain RGM. Method must exclude reactive gaseous mercury, however, normal particulate filters have problems in that they retain RGM.

28 Tekran Automated Mercury Speciation Model Principles of Operation Sampling Phase Sampling Phase Quartz, regenerable particulate filter (RPF) captures fine fraction (< 2.5 um) particulates after air has passed through impactor and denuder Quartz, regenerable particulate filter (RPF) captures fine fraction (< 2.5 um) particulates after air has passed through impactor and denuder Desorption/Analysis Phase Desorption/Analysis Phase Zero air used as carrier Zero air used as carrier Downstream pyrolyser is activated first Downstream pyrolyser is activated first RPF is heated to desorb captured particulates RPF is heated to desorb captured particulates

29 Tekran Automated Mercury Speciation Model 1135 – Particulate Mercury Monitor Unit stacks on top of Model 1130 Unit stacks on top of Model 1130 Allows simultaneous deter- mination of Hg 0, RGM and HgP Allows simultaneous deter- mination of Hg 0, RGM and HgP Detection limit ~ 1 pg/m 3 Detection limit ~ 1 pg/m 3

30 Tekran Automated Mercury Speciation Model 1130 & Model 1135 Flow Path

31 Tekran Automated Mercury Speciation Ambient Air Speciation

32 Tekran Automated Mercury Speciation Conclusions - HgP A quartz RPF quantitatively collects particulate mercury but does not retain Hg 0 A quartz RPF quantitatively collects particulate mercury but does not retain Hg 0 HgP collected on a denuder is thermally desorbed and converted to Hg 0 in the pyrolyzer HgP collected on a denuder is thermally desorbed and converted to Hg 0 in the pyrolyzer Carbon based particulate matter on the filter is oxidized to CO 2 during desorption cycle Carbon based particulate matter on the filter is oxidized to CO 2 during desorption cycle Filter is usable for 1 – 2 weeks before requiring restuffing Filter is usable for 1 – 2 weeks before requiring restuffing


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