ORD Testing to Support Developme

EPA Performance Specification 18 for H

Office of Research and DevelopmentNational Risk Management Research Laboratory. 

38th Stationary Source Sampling & Analysis for Air 

March 4th, 2013 

Point Clear, AL

Jeff Ryan and Ed Brown

US EPA – Office of Research and Developme

Peter Kariher

ARCADIS US, Inc
Topics

• Update on HCl measurements testing• Update on HCl gas standards• Traceability Protocol for HCl Evaporative Gener

1
2

Reference Method Agreement

M26A Avg.

ppmv (wet)

FTIR

ppmv (wet)

Absolute

Difference

ppmv

Re

Diffe

Fuel/Coal Type RD 

Natural gas 0.27 6.3% 0.19 0.08 Natural gas 0.59 1.1% 0.59 0.00 Natural gas 2.02 1.7% 1.98 0.04 

Bituminous 23.36 0.7% 24.37 1.01 Bituminous 25.06 0.7% 25.87 0.81 Bituminous 20.15 3.7% 25.71 5.56 Bituminous 23.42 0.3% 26.46 3.04 

PRB 3.44 1.0% 3.82 0.38 PRB 3.58 0.0% 3.99 0.41 PRB 4.08 8.4% 4.25 0.18 

Lignite 2.03 9.4% 2.34 0.31 Lignite 2.33 0.3% 2.52 0.20 

Bituminous 30.35 2.1% 33.14 2.79 Bituminous 29.86 1.1% 32.30 2.45 

Average 2.6% Average 
Gas Standard Testing

• Compressed Gases:

–Have come a long way

• Lower levels• Stable

–Now being used for PS-18

Testing

–Evaluating dilution for low levels

3

• Hovacal/Evaporative Generators:

–Alternative to compressed gases–Testing to evaluate comparability–Testing to determine uncertainty of gases generated–Testing to inform Traceability Protocol 

3/26/2013 

AirgasTag 

Value

FTIR 

Measured 

Value Agreement

ppm ppm % 

1.843 1.846 0.2 4.600 4.525 -1.6 9.280 9.439 1.7 
Wet and Dry HCl Gas Compari

Wet Gas (HovaCAL) - Moisture Fixed at 8% 

Gas Cylinders with Gas Divider

Set Point

Conc.

(ppmv)

Theoretical

Conc.

(ppmv)

FTIR

Measured Conc. 

(ppmv)

Relative 

Difference

%

RSD 

(%)

0.5 0.53 0.49 -7.9% 6.6%

1 1.02 1.02 -0.3% 4.3%2 2.09 2.06 -1.6% 1.8%5 5.31 5.37 1.2% 0.9%9 9.00 8.79 -2.3% 1.0%

Set Point

Conc.

(ppmv)

Theoretical

Conc.

(ppmv)

FTIR

Measured Conc. 

(ppmv)

Relative 

Difference

%

RSD 

(%)

0.5 0.45 0.44 -2.3% 8.5%

1 0.90 0.88 -2.0% 4.1%2 2.25 2.25 0.2% 1.9%

5* 4.60 4.49 -2.4% 1.8%

10* 9.28 9.15 -1.4% 0.5%

* = Gas direct from cylinder
NIST Status

•Establishing capabilities to provide traceabi

–Developed multiple working ref HCl gas cylinders 

(1, 8-14ppm)

• Primary HCl standard = 400 ppm

–NIST concentrations confirmed by VSL 

(within uncertainties)

–Have characterized HCl RGMs from 2 gas vendo

• HCl concentrations 8-12 ppm• Uncertainties ~1.5%, one year certification (for now)• RGMs will be returned to vendors soon

–Recognize the need to expand the range of conc

• Targeting vendor supplied concentrations from 0.5 ppm 

5
Gas Vendor Status

• Multiple gas vendors are now providing low level 

(<10 ppm) HCl gas standards

–Targeting <1 ppm gases

• Based on NIST RGM uncertainties, out-the-door un

for commercial HCl gases expected to be well belo

• Current commercial gases have agreed well with F

reference spectra and have been used to conduct fCalibration Error testing

• Examining stability for long-term certifications• Evaluating HCl-specific regulators for improved per• Discussing guidance for cylinder use

6
HCl Gas Standard Availabilit

7

Low Mid Hig

Span 10% 30% 50% 60% 80% 

ppm ppm ppm ppm ppm ppm 

2 0.2 0.6 1.0 1.2 1.6 

5 0.5 1.5 2.5 3.0 4.0 

10 1.0 3.0 5.0 6.0 8.0 20 2.0 6.0 10.0 12.0 16.0 50 5.0 15.0 25.0 30.0 40.0 

Gases available from NIST and vendors

Gases available from NISTGases available from vendors

Gases available from evaporative generators only
EPA Traceability Protocol for Qualification 

Certification of Evaporative Hydrochloric AGenerators and Humidification of Gases fro

• Qualification Tests

–Performed by manufacturer–Demonstrates the adequacy of each model, not each un–Manufacturer’s Disclosure defines for customer the rang

conditions under which the model can operate reliably

• Certification

–Unit-specific – serial number recorded on documentatio–Performed by manufacturer, but may be repeated by cu

third-party if in-field recertification becomes necessary

–Defines the relationship between reported concentration

corresponding NIST-traceable concentrations.
Qualification Tests (tentativ

• Setpoint Repeatability (hysteresis)• Thermal Stability• Back Pressure• Supply Pressure• Line Voltage
Certification Assumptions

• Assumptions (based on qualification tests)

–The “mass balance” holds – no leaks, losses, or conversi–All component measurement devices deliver stable and r

readings over their range of operation

–The performance of the overall calibration gas delivery de

reproducible over its range of operating conditions
Certification

• NIST-traceable reference devices/materials requi

–HCl source material – liquid or gaseous standard with tra

concentration

–Gas flow(s) – independent traceable standard(s), with un

certification, covering the full range of gas flows required

–Liquid flow(s) – usually performed by gravimetric means, 

balance calibrated with NIST-traceable weights

• Output Verification

–Demonstrates that the actual HCl output concentration a

the calculated concentration from the NIST-traceable inp

–Comparison with NIST-traceable bottled gas
Uncertainty of Certified Out

• Calculated by propagation of uncertainty from inp

concentrations and operational measurements

–Concentration of certified HCl liquid or gas standard–Uncertainty of dilution process (if used) to make liquid w

solution from commercial standard solution

–Liquid and gas feed rates, including reproducibility

• Standard uncertainties of these components are 

combined to calculate combined uncertainty.

• Combined uncertainty is multiplied by a coverage 

of 2 to get expanded uncertainty.
13

Calculated Uncertainty Compon

1/ 2

2 2

2

2         A F CS WS U U U U

Where:

UWS = Uncertainty in the concentration of the working solution (%)

UCS = Expanded uncertainty of the commercial standard, with a coverage factoUA = Uncertainty of the aliquot weight or volume (%)

UF = Uncertainty of the final, diluted standard weight or volume (%)

Liquid HCl Concentration:

    1/ 2 2 2

1

2

2

( 1)

1

         J LFD LFD LFD U JJ U j Jj LFR LFD j

    1/ 2 2 2

1

2

2

( 1)

1

         J GFD GFD GFD U JJ U j Jj GFR GFD j

Liquid Feed Rate:Where:

ULFR = Uncertainty of the liquid feed rate (%)

J = Number of independent liquid feed determinations

ULFD = Uncertainty of an independent liquid feed determination (%)

LFR = Liquid feed rate as determined (g/min or mg/min)

Where:

UGFR = Uncertainty of the gas feed rate (%)

J = Number of independent gas feed determinations

UGFD = Uncertainty of an independent gas feed determinationGFD = Gas feed rate as determined (l/min or ml/min)

Gas Feed Rate:
14

Expanded Combined Uncertai

 

1/ 2

2 2

2

2 2

       OUT   WS  UGFR ULFR TFR GFR U U

Where:

UOUT = Uncertainty in the delivered concentration (%)

UWS = Uncertainty in the concentration of the working solution (%)

GFR = Gas feed rate measurement (dslpm)

TFR = Total flow rate, including dry gas and evaporated liquid measurements (

UGFR = Uncertainty of the gas feed rate (%)ULFR = Uncertainty of the liquid feed rate (%)

GFR

MW

LFR V TFR

W

std   

ˆ

Where:

LFR = Liquid feed rate measurement (g/min)

= Standard molar volume from ideal gas law (22.4 liters/mol @ 0°C, 1 atm

MWW = Molecular weight of water (18.016 grams/mol)

Vstd

ˆ

J

LFD

LFR

J

j

 j





1

J

GFD

GFR

J

j

 j





1
15

Example Uncertainty Calculati

0.25%

2

1/ 2

2 2

2



        A F CS WS U U U U

UCS = 0.50%UA = 0.03%UF = 0.04%

Liquid HCl Concentration:

    0.21%

( 1)

1

1/ 2

2

2

1

2

2



         J LFD LFD LFD U JJ U j Jj LFR LFD j

    0.88%

( 1)

1

1/ 2

2

2

1

2

2



         J GFD GFD GFD U JJ U j Jj GFR GFD j

Liquid Feed Rate: J = 3

ULFD = 0.009% 0.016% 0.013%LFD = 0.5218 g/min 0.5283 g/min 0.5267 g/minJ = 2 UGFD = 0.4% 0.4%GFD = 8.812 slpm 8.708 slpm

Gas Feed Rate:
16

Example Uncertainty Calculati

2   

1/ 

2 2

2

2

       OUT   WS  UGFR ULFR TFR GFR U U

UWS = 0.25%

UGFR = 0.88%ULFR = 0.21%

GFR lpm MW LFR V TFR W std 9.413

ˆ

 





LFR = 0.5256 g/min

= 22.4 liters/mol 

MWW = 18.016 grams/molGFR = 8.760 lpm

Vstd

ˆ
Questions ...

17