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California Desert Air Working Group

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Presentation on theme: "California Desert Air Working Group"— Presentation transcript:

1 California Desert Air Working Group
Ultra Low Level HCl CEMs for Coal Combustion Facilities Using FTIR and Associated Performance Specifications California Desert Air Working Group November 13-14, 2013 Las Vegas, NV Peter G. Zemek, Ph.D. MKS Instruments On-Line Product Group 2 Tech Drive, Suite 201 Andover, MA Tel: MultiGas™ FT-IR Automated HCl CEM Systems

2 Discussion 40 CFR Parts 60 and 63 - (NESHAP) for the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants - Meet Standard by 2015 EPA Utility MACT (40 CFR Part60, Subpart UUUUU, EPA – 1,350 Units Affected Continuous Monitoring (HCl) from new and existing coal and oil-fired (HF) emissions Cement - 3 ppmv HCl, (3.8 7% O2), EGU – 1 ppmv HCl Instrument HCl Quantification - Rule of Thumb 20% below Emissions Regulation, So need 0.2 ppm Current MKS FTIR is 50 ppb Use Performance Specification 15, App B and Procedure 1 of Appendix F until new PS (20 yrs. old) New PS-18 in development specific to HCl (Spring 2014) Initial Instrument Qualification On-going QC promulgated separately

3 Performance Specifications for FTIR CEMS
PS-15 For Extractive FTIR CEM Systems in Stationary Sources Reference Method RATA Run Comparisons – Follow PS 2 Specifications and Test Procedures for SO2 and NOX CEM in Stationary Sources – WILL BE CHANGED (M320/ASTM D ) Draft PS-18 and Test Procedures for HCl CEMS in Stationary Sources - Spring 2014 Tests on-going at EPA RTP-NC NIST traceable standards now available 1-20 ppmv Bal N2. EPA has a 1 ppm NIST traceable standard. We match against HITRAN - High Resolution Transmission -Air Force Research Laboratories (1960s) Harvard-Smithsonian Center for Astrophysics, Cambridge MA, USA. Worldwide standard of atmospheric molecular transmission and region of the EM spectrum

4 FTIR Reference Methods for CEMS Validation and RATA
Method 301—Field Validation of Pollutant Measurement Methods From Various Waste Media Method 320* - Measurement of Vapor Phase Organic and Inorganic Emissions by Extractive (FTIR) (Includes FTIR Protocol) Method 321** - Measurement of Gaseous HCl Emissions at Portland Cement Kilns by FTIR Spectroscopy ASTM D Standard Test Method for Determination of Gaseous Compounds by Extractive Direct Interface Fourier Transform Infrared (FTIR) Spectroscopy *1 of 2 RM for EGU **Only acceptable RM for Portland Cement MACT

5 Validation and On-Going HCl CEM PS-18
Before Installation, instrument manufacturer must perform: Linearity Detection Limit Cross Sensitivity After Installation to Validate must perform: RATA Test on Other than HCl compounds Reference Method Test HCl - EPA-M321 RATA Includes Dynamic Spike 7 day drift test Daily and On-Going (all automated) Zero Dynamic Spike or Dry Cal Span (Wet or Dry) Periodic RATA Provide 30 day rolling avg HCl

6 Advantages of FTIR No training needed Measurements done Hot-Wet
Required for polar components HCl, HF Works with High CO2 and H2O No Chemical Conversions Multiple components Simultaneously THCs, HCl, HF, VOCs, NOx, SO2, etc. Additional components: No hardware change Can be added in the field Simple Operation No daily maintenance No Daily Calibration High sensitivity gas cell small volume (200mL) long path length (5.11m) No training needed Software alerts to any malfunction Only laser replace and cell cleaning Fast (1 Hz or 5 Hz)


8 What is FTIR? Fourier Transform Infrared Spectroscopy (Spectrometry)
Fourier Transform: mathematical conversion from the time domain to the frequency domain Infrared: Low energy wavelengths longer than visible light (heat) Spectroscopy: study of the electromagnetic spectrums electrical and magnetic fields FTIR uses an “Interferometer” -- a device which splits focused light, optically retards it and recombines it to produce an optical interference pattern resulting in an Interferogram. A computer converts the Interferogram to an Absorbance spectrum which is Linear

9 MKS IR Spectroscopy Hardware
Source: Blackbody (Hot Silicon Carbide ~ 1300 K) Modulator: Interferometer Sample: Vapor (Gas Cell, 10, 5.11m, 35cm, or 2cm path lengths) Detector: Mercury Cadmium Telluride (MCT) Quantum Detector cooled by Thermoelectrically (TE) Peltier

10 The FT-IR Light Modulator Creating the Interferogram
HeNe Laser monochromatic light Fixed Mirror Beamsplitter Moving Mirror Optical Retardation - difference between the distance the light travels in the two arms of the pathway above. If the difference is 0 (same length of travel) there will be Constructive interference (all light passes to the detector) otherwise there is interference between the beams and less light gets to the detector. At 1/4 wavelength displacement of the moving mirror the optical retardation is 1/2 wavelength which causes destructive interference and no light reaches the detector. Constant velocity movement of the mirror causes a sinusoidal response seen by the detector. Laser light is very narrow and is used to calibrate the exact positions of when the Zero crossing occur. IR Source To Gas Cell & Detector

11 FTIR From Igram to Spectrum
Create Interferogram then send to detector (Modulator) Amplify Interferogram (preamp) then digitize it (A/D converter) Send digital signal to computer (PC) Apply Fourier Transform math to Interferogram, result is Spectrum (I) Remove background noise signals (Io) from Sample (I) Result is Absorbance gas spectrum (A) used to identify the different species Show full water region

12 Background and Sample Absorbance = - Log (I/Io) BACKGROUND (Io)
N2 Purge SAMPLE (I) 1000 ppm NH3 Single Beam Background N2 purging instrument then background collected (eg. is 1cm-1) Single Beam Sample Sample gas flowing through cell (eg. is 1000 ppm NH3 at 1cm-1) Absorbance = - Log (I/Io)

13 Absorbance is Proportional to Concentration
Absorbance = - Log (I/Io) Absorbance =  • C • path FFT of Sample 1000 ppm NH3

14 FTIR Analysis Method Analytical Method
Classical Least Squares (CLS) then Beers Law, Abs = a b c  measured spectrum a absorptivity coefficient or ε  from calibration b path length  fixed (5.11 meter) c sample concentration (calculated)  what we want Canned Method - No user input necessary Hot and Wet, No sample change – No ionization No pressure drop across sample cell 1 scan/second data point every 30 seconds 40 sample cell turnovers per minute Self -validating sample method Cement – Only acceptable reference method EPA M321

15 Classical Least Squares
Model Based on Beer’s Law Relatively fast computationally More complex mixtures Wavelengths used need to be greater than #components Noise reduced as #s increase 1 2 a b a+b WAVELENGTH ABSORBANCE CLS Spectral Analysis  Finds factors for all reference spectra in method/recipe to recreate the sample spectrum Classical Least Squares K contains the pathlength and the molar absorptivity coefficient for each component at a particular wavelength.

16 Powerful Technique - CLS for HCl Measurements with FTIR
Sample (white) with 5 ppm HCl and 12% water (red) H2O subtraction HCl peaks clearly visible after H2O subtraction

17 Powerful Technique - CLS for HCl Measurements with FTIR
HCl calibration peaks (red and green) HCl subtraction After HCl subtraction, only noise left

18 Examples of Pre-Abatement Coal Fired (Cement Plant) Gas Concentrations Measured by FTIR
HCl 5-300 0-5 0-4 <1 2-4 SO2 0-60 0-200 0-240 0* NOx * ~ 150 ~ 800 CH2O 5-25 0-3 3-9 2-3 ~ 20 ~ 3 *NH3 0-150 0-40 0-80 0-50 ~30 0-15 CO * * * ~ 300 CH4 ~ 2 ~ 5 * Also includes periodic high concentration spikes This slide compares the measurements requirements in terms of sensitivity, accuracy, etc… for US standards and European standards. IN the next few slides, I am going to go through how FTIR can meet all these requirements. All values in ppmv (or ppm) Includes data from non-US plants Concentration ranges e.g. min reading. Note: max reading, not rolling averages Data spanning few minutes to few days H2O and CO2 also measured with targets (cost effective) * - Not measured with high sensitivity instrument (but can do high levels)

19 Examples of HCl Concentration Profiles at Cement Plants – RM On/Off
Raw Mill OFF Raw Mill ON HCl Concentration (ppm) Time 19

20 TÜV ranges & uncertainties MKS 2030D TE9 CEM FTIR
Gas comp. Cert. range Supp. range 1 Supp. range 2 ELV U/C U/C req. NH3 0-10 mg/m3 0-75 mg/m3 - 10 mg/m3 6.2% 30.0% CO 0-300 mg/m3 mg/m3 50 mg/m3 7.5% SO2 mg/m3 7.0% 15.0% NO 0-200 mg/m3 0-400 mg/m3 130 mg/m3 6.8% NO2 0-50 mg/m3 0-100 mg/m3 mg/m3 4.1% HCl 0-15 mg/m3 0-10 ppmv 0-90 mg/m3 8.1% HF 0-3 mg/m3 1 mg/m3 19.3% CH4 22.5% CO2 0-25% 3.3% H2O 0-40% 3.4% N2O 0-500 mg/m3 4.5% 1 ppm HCl = 1.49 mg/m3

21 FTIR Suppliers - TÜV Ranges & Uncertainties
SO2 Cert. range Supp. range 1 Supp. range 2 Rel. U/C MKS 0-75 mg/m3 0-300 mg/m3 mg/m3 7.0% of 50 mg/m3 Comp 1 mg/m3 9.4% of 50 mg/m3 Comp 2 10.5% of 50 mg/m3 Comp 3 - Comp 4 11.5% of 50 mg/m3 HCl Cert. range Supp. range 1 Supp. range 2 Rel. U/C MKS 0-15 mg/m3 0-90 mg/m3 0-200 mg/m3 8.1% of 10 mg/m3 Comp 1 - 12.0% of 10 mg/m3 Comp 2 0-150 mg/m3 12.2% of 10 mg/m3 Comp 3 12.8% of 10 mg/m3 Comp 4 11.4% of 10 mg/m3

22 EPA Test Facility – PS18 RTP, NC MKS Reference Method -Anchor
ORD’s Multi-Pollutant Combustion Research Facility 4M Btu/h down-fired combustor firing coal and/or NG Multiple pollution control configurations possible SCR, ESP, FF, Wet Scrubber Duct injection of gases to control emission profiles and combinations HCl, SO2, NOx, CH4, CO, NH3, H2O, CH2O All CEMS and RM measurements from same basic location

23 EPA REFERENCE METHODS – MKS FTIRs - Anchors for Testing (EPA and Industry)
Looking at 3 different high resolution FTIR analyzers Focus on DLs, measurement quality and RM performance at very low HCl levels LN2, TE9, HS Point of reference for HCl Gas Standards

24 NEW: High-Sensitivity FTIR HCl Analyzer for CEM
HCl detection limit 0.03 ppm (30 ppbv) plus bias Hot and Wet – 200mL Sample Volume No liquid nitrogen (LN2) needed No N2 Background → easier integration than standard FTIR – turn on and go No Calibration Needed– “Canned” Method Can measure HCl, CH2O, HF, H2O, N2O, CH4 with similar high sensitivity – or ELIMINATE Spectral Regions of no concern –hardware based

25 Installations -Two CEM systems two Cement Plants –Passed PS18 RATA
1 is almost 1 year old and 2 other HCl CEM going in -Two in Hildago, Mex. CEM PS-15 Cal Data 2 years Running

26 Transferrable Hardware & Software

27 Detector/Hardware Influences High Sensitivity System HCl, HF, CH4, H2O, N2O, CH2O
TE9u CEM LN2-16u MCT (77K) TE-HS CEM Sensitivity (signal) <noise >S/N IR Band-pass Filters spectral region

28 EXAMPLE of No Cross Sensitivity
No change in HCl concentration 900 ppm CH4 and 6% H2O

29 Staged Blowback Filtration 80 psig

30 MKS FTIR CEM Data 15 Days RM and PS18 require a Dynamic Spike
Replace 10% CEM flow with spike material Spike10 x 50% of what’s found (3 ppm native, 15 ppm spike) Result Theoretical ~3+1.5 = 4.5 ppm HCl CEM Recovery +-20%, RM is 30%

31 H2O vs. HCl in CEM Cement Extractive System
No Filter Change or Blowback – 4 months CEM passes PS-15/Draft 18 with Sig Filter Cake, until Dry Gas is introduced Dropping H2O to < 0.5%, Filter cake sublimes to HCl gas, Conc. Inc. rapidly Then, comes back to Steady-State when H2O > 0.5%

32 HCl CEM Dynamic Spiking

ASTM D /03 LOD – Measure of Precision EPA Method 320 – Max Anal Uncertainty (MAU) MDC =2 stdev at 95% CI from Residual NIOSH 3800 Method 1 - LOD (ambient) Examines Interference Residuals

34 Detection Limits - Which One?
1 set of data

35 Compliance Software MDC/LOD/MAU/OFC EPA-M320,ASTM D6348-12

36 Manual Check TE-HS LOD Software Included
Goodness of Fit-2x sigma Manual Check TE-HS LOD Software Included CH4 12 ppm HCl 30 ppb

37 Comparison of HCl Calibrations Precision

38 Comparison of MKS FTIR Analyzers Solutions for HCl
HCl DL* (30 sec) Main Components Measured Information Broadband CEM TUV Certified EPA Certified <300 ppb HCl, SO2, NOx, CO, CO2, H2O, NH3, HF, N2O, CH4, CH2O No LN2 needed Requires daily N2 Zero High-sensitivity HCl FTIR <30 ppb HCl, Formaldehyde, HF, CO, CO2, CH4 No daily N2 Zero Uses Auto-Reference method * Detection Limit based upon 3σ in 30% H2O and 25% CO

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