ISO 17025 Accreditation of ISO 17025 Accreditation of Stack Gas Calibration Gas Mixtures
The Air Quality and Emissions Show AQE 2013 AQE 2013
Telford, 13th–14th March 2013
Sant Celoni’s Specialty Gases Laboratory
J A è Josep Aragonès
Esteban Elías
Dr. Gordon Ferrier
1
Industrial EmissionsIndustrial Emissions
European directives
- Greenhouse Gas EmissionsGreenhouse Gas EmissionsDirective 2003/87/EC and others
- The Waste Incineration Directive - The Waste Incineration Directive Directive 2000/76/EC
- Large Combustion Plants Directive Directive 2001/80/EC
Requirement for monitoring CO2, NOx, SO2, CO, TOC, HF, HCl
Analysis of NO/SO2/CO/CO2Analysis of NO/SO2/CO/CO2
The calibration of analysers using binary mixtures can often lead to errors
in the analysis of stack gases due to cross-sensitivity effects occurring within
the analysers
Errors due to cross sensitivity can prove expensive (e.g. during any
emissions trading process)g p )
Calibration using binary mixtures often requires a large number of
calibration cylinders and often do not take into account cross sensitivity
effects
There is therefore a need for suitable accredited multi-component
calibration gas mixtures. calibration gas mixtures.
Q tif i i t f (I)Quantifying cross interference (I)
A h
1) Preparation of several mixtures containing one possible interfering
Approach
1) Preparation of several mixtures containing one possible interfering
and the component to be analyzed.
I diff i In different concentrations.
In different ratios.
2) Calibration with binary standards.
3) Calculation of the interfering effect.
Q tif i i t f (II)Quantifying cross interference (II)
N2
NO/N2
Gas mixer Analyzer
CO2/N2
Q tif i iti it (III)Quantifying cross sensitivity (III)Analysis of constant levels of NO in the presence of varying levels of CO2Analysis of constant levels of NO in the presence of varying levels of CO2
(chemiluminescence analyzer)
NO concentration (ppm)
CO2 concentration (%)
Analysis results (ppm NO)
Increase due to CO2 (ppm NO)(pp ) ( ) (pp ) (pp )
5005.4 20 5077.2 71.85005.4 17 5069.9 64.55005.4 14 5059.2 53.85005.4 11 5045.6 40.25005.4 8 5031.6 26.25005.4 4 5023.2 17.8
Quantifying Cross Interferences (IV)Quantifying Cross Interferences (IV)Analysis of varying levels of NO in the presence of varying levels of CO2
Interference CO in NO
(chemiluminescence analyzer)
60.00
70.00
80.00
OInterference CO2 in NO
20 ppm NO
30.00
40.00
50.00
or p
pm
NO 20 ppm NO
50 ppm NO
100 ppm NO
500 ppm NO
10 00
0.00
10.00
20.00
0 5 10 15 20 25
Erro 1000 ppm NO
2500 ppm NO
5000 ppm NO
-10.00% CO2
Error (ppm NO)= 0.00081176 [NO] [CO2] ‐ 0.147528
Q tif i C I t f (V)Quantifying Cross Interferences (V)Analysis of varying levels of NO in the presence of varying levels of CO2y y g p y g 2
(chemiluminescence analyzer)
100100.2
torInterference CO2 in NO
99.299.499.699.8
ren
cefa
ct
98.498.698.8
99
0 5 10 15 20 25
Inte
rfer
0 5 10 15 20 25
% CO2
Interference factor (If) = ‐0.0007 [CO2] + 0.9999( f) [ 2]
Q tif i C I t f (VI)Quantifying Cross Interferences (VI)
Analysis of Varying levels of CO in the Presence of Varying Levels of CO2
(NDIR analyzer)
1.50
CO
10 ppm CO
1 00
1.50
CO
45 ppm CO1.00
CO
100 ppm CO
0.00
0.50
1.00
0 10 20 30rror
pp
m C
-0.50
0.00
0.50
1.00
0 10 20 30
rror
pp
m C
-1.00
0.000 10 20 30
rror
pp
m C
0 10 20 30Er
% CO2-1.00Er
% CO2-2.00Er
% CO2
Interferences are calculated for 3 different CO2 ranges
Quantifying Cross Interferences (VII)Quantifying Cross Interferences (VII)Analysis of varying levels of SO2 in the presence of varying levels of NO2
(NDIR UV analyzer)
Interference NO2 in SO2
3
3.5
4
m S
O2
Interference NO2 in SO2
1
1.5
2
2.5
or p
pm
20 ppm SO2
80 ppm SO2
145 ppm SO2
0
0.5
0 10 20 30 40 50 60
Erro
ppm NO
145 ppm SO2
Error (ppm SO2)= 0.074037 [NO2] – 0.000131 [NO2] [SO2] ‐ 0.009827
ppm NO2
S f I t fSummary of Interferences
ANALYZER 1 NO /NOx(CLD)
ANALYZER 2 NO/NOx (CLD)
SO2
(NDIR) SO
2(UV Fluorescence)
SO2
(NDUV) CO
(NDIR)
NO/NOx
‐‐‐‐ ‐‐‐‐ NO YES NO YES
SO NO YES ‐‐‐‐ ‐‐‐‐ ‐‐‐‐ YESSO2
NO YES YES
CO NO NO NO NO NO ‐‐‐‐
CO2
YES YES NO YES NO YES
NO2
‐‐‐‐ ‐‐‐‐ NO YES YES NO
U t i t C l l tiUncertainty Calculation
Uncertainty due to the Calibration Standards
Uncertainty due to Analytical InstrumentationResolutionRepeatabilityLinearityI t di t P i iIntermediate PrecisionFlowPressure and Temperature
Uncertainty due to the corrections
)( ti( l i ))(C 22 n)(correctiou(analysis)u)u(C 22i
Did we miss any cross sensitivity effects?Did we miss any cross sensitivity effects?
Are the corrections correct?Are the corrections correct?
I t i E i
PT Stack Gas Round 11 (VSL)
Intercomparison Exercises
319 ppm 302 0 ppm 169 5 ppm 12 00 % 51 70 ppm Balance
PT-Stack Gas Round 11 (VSL)
Reference value 319 ppmNO
302.0 ppmSO2
169.5 ppm CO
12.00 % CO2
51.70 ppmC3H8
Balance N2
Analysis 320.1 ppm 302.9 ppm 169.7 ppm 11.96 % 51.60 ppm
Compatibility index 0 17 0 22 0 04 0 35 0 15Compatibility index 0.17 0.22 0.04 0.35 0.15
Compatibility index =analysisdards
analyisisdards
UU
CC2
tan2
tan
≤ 1
A l i f NPL P i R f M t i lAnalysis of NPL Primary Reference MaterialsPRM 20.3 ppm NO 20.0 ppm SO2 4957 ppm CO 19.84 % CO2 Balance N2
Analysis 20 42 ppm 20 03 ppm 4968 ppm 19 79 %Analysis 20.42 ppm 20.03 ppm 4968 ppm 19.79 %Compatibility index 0.23 0.18 0.31 0.37
PRM 20.1 ppm NO 4978 ppm SO2 19.9 ppm CO 20.08 % CO2 Balance N2
Analysis 20.26 ppm 4966 ppm 20.13 ppm 20.02 %Compatibility index 0.31 0.24 0.45 0.31
PRM 1008 0 ppm NO 1003 0 ppm SO 1005 0 ppm CO 20 08 % CO Balance NPRM 1008.0 ppm NO 1003.0 ppm SO2 1005.0 ppm CO 20.08 % CO2 Balance N2
Analysis 1015.3 ppm 1002.4 ppm 1007.5 ppm 20.03 %Compatibility index 0.41 0.14 0.20 0.27
PRM 1004.0 ppm NO 146.0 ppm SO2 1000.0 ppm CO 8.026 % CO2 Balance N2
Analysis 1008.8 ppm 146.12 ppm 1000.9 ppm 8.023 %Compatibility index 0.25 0.10 0.06 0.16
PRM 4986 ppm NO 19.7 ppm SO2 20.0 ppm CO 19.99 % CO2 Balance N2
Analysis 5011.4 19.77 ppm 19.52 ppm 19.96 %Compatibility index 0.29 0.22 0.57 0.21
Air Products Accredited Scope (Stack Gases)(Stack Gases)
Concentration Uncertaintyrange y
NO 9 ppm ‐ 5000 ppm 2.5% ‐ 1%
SO 9 5000 2 5% 0 9%SO2 9 ppm ‐ 5000 ppm 2.5% ‐ 0.9%
CO 9 ppm ‐ 5000 ppm 2% ‐ 0.9%
CO2 300 ppm ‐ 21% 1.5% ‐ 0.75%
N2 Balance
Air Products Accredited Scope (Environment)
Concentration Uncertainty
(Environment)
range Uncertainty
NO Balance N2 9 ppm ‐ 5000 ppm 2.5% ‐ 1%
SO2 Balance N2 9 ppm ‐ 5000 ppm 1.5% ‐ 0.9%
NO2 Balance N2/Air 9 ppm ‐ 400 ppm 4% ‐ 3%
Concentration range Uncertainty
CO 9 ppm ‐ 5000 ppm 2% ‐ 0.9%
CO2 300 ppm ‐ 21% 1.5% ‐ 0.75%
O2 1% – 28% 0.8% ‐ 0.5%
N2 Balance
Air Products Accredited Scope ( O )(MOT)
Concentration Uncertaintyrange y
C3H8 1 ppm ‐ 3500 ppm 2.5% ‐ 1%
CO 900 11% 0 75%CO 900 ppm – 11% 0.75%
CO2 300 ppm – 21% 1.5% ‐ 0.75%
O2 1000 ppm ‐ 28% 4% ‐ 0.5%
N2 Balance
ConclusionConclusion
The Calibration of Stack Gas Emission analysers by using binary
calibration mixtures can lead to errors
Analytical cross sensitivity can vary depending on the technique,
the brand and the model of the analyzer
There is a need for accredited NO/SO2/CO/CO2 in N2 multi-
component calibration gases to support pollution monitoring co po e ca b a o gases o suppo po u o o o g
Thank youThank you…tell me more
4/3/201320
