Review of ISO10723 Performance Test Frequency. By Anwar Sutan

Transcription

1 Review of ISO10723 Performance Test Frequency By Anwar Sutan

2 Agenda Objectives Regulation Requirements Issues in analyzer system ISO Intention and Practices Case Studies Alternative method ISO other method comparison Summary

3 Objectives To discuss the possibility of reducing ISO Performance test freq To consider other Health Checks to catch inyear GC issues

4 REGULATORY REQUIREMENTS

5 Regulatory Requirements (EU ETS) The commission of the European communities decision 18/7/2007 Commission Regulation 601/2012 on the monitoring and reporting of greenhouse gas emissions It does not mention ISO anymore

6 Regulatory Requirements (EU ETS) Regulation from 2007 is much more quoted in comparison to the regulation from 2012 Or Wording validation is interpreted as ISO Performance Test

7 Regulatory Requirements (EU ETS) Determination of Calculation Factors based on analyses: Use of laboratories Use of online gas chromatograph Use of offline chromatograph Precedence Operators who determine calculation factors using laboratories did not get any audit points

8 Regulatory Requirements (EU ETS) When using laboratory for calculation factors determination: There is minimum frequency of analysis in terms of sampling plan

9 Regulatory Requirements (EU ETS) Different frequency is allowed if: Based on historical data, any variation does not exceed 1/3 of the uncertainty value to which operator has to adhere to Using the required frequency would incur unreasonable cost

10 Regulatory Requirements (DECC Guideline) DECC Guideline Issue DECC may require operators of relevant systems to quantify at regular intervals the linearity and repeatability of fiscal gas chromatographs 7.6. The gas chromatograph should be subject to a health check, the frequency of which may be determined on a risk-based analysis. DECC may insist on ISO certification Calibration gas should lie within linear response of the analyser

11 ISSUES IN ANALYSER SYSTEM

12 Issues in Analyzer System Heavy end drop out Linearity and repeatability, leakage etc GC Pressure Let Down System Human Error / Procedure Cal gas Stratification / high uncertainty cal gas

13 Issue Sensitivity Issue Errors found Heavy end drop out in PLS More than 150K /month (0.8%) Calibration gas error More than 50K /month (0.35%) Human error More than 300K /month (1.4%) Linearity from GC (Up to 20% difference in Methane) 0.075% in CV (Acceptable CV uncertainty of 0.2%)

14 Validation / Health Check

15 ISO INTENTION AND PRACTICES

16 ISO INTENTION To quantify GC repeatability To quantify GC linearity To determine GC Performance benchmark Errors (bias) Uncertainties (from calibration gas and repeatability) Overall bias Combination of errors and uncertainty Overall to validate that GC is working correctly (Health Check) There is no calibration being done during this process

17 Current ISO Practices Many operators do it once a year / once every two years Range of gas is very often not as per actual concentration

18 Current ISO Practices Linearization constants are seldom implemented (only 4 out of 30 GC on case study has multilevel calibration constant applied) Some GC don t have these feature inside the GC

19 Current ISO Practices The benchmark is only valid if the GC maintains performance characteristics measured on the day of calibration Many operators send a GC specialist prior to ISO test Extra cost

20 CASE STUDIES

21 Case study Two tracking GC of which one failed ISO test MLC constants applied vs single point calibration mole% Errors masked by polynomial curve ISO test GCAS ISO test

22 Case Study 1 Performance test failed outside the actual gas range

23 Case Study 2 MLC mole% vs single point calibration mole%

24 Case Study 2 MLC mole% vs single point calibration mole%

25 Case Study 2 MLC mole% vs single point calibration mole%

26 Case Study 2 MLC mole% vs single point calibration mole%

27 Case Study 2 CV and Relative Density

28 Case Study 2 CV and Relative Density

29 Case Study 2 CV and Relative Density

30 Case Study 2 CV and Relative Density

31 Case Study 3 ISO Performance check may be performed on Chromat with: Valve timing error Peak cuts The benchmark is only valid if the GC maintains performance characteristics measured on the day of calibration

32 Case Study 3 ISO10723 Polynomial constants are formed under faulty conditions Errors are masked by polynomial curve

33 Case Study 4 ISO10723 GCAS monitoring ISO10723 was done

34 Case Study 4 ISO10723 GCAS monitoring ISO10723 was done

35 Case Study 4 Could we reduce the ISO test frequency in this case?

36 WHAT IS THE ALTERNATIVE?

37 i-vigilant s GCAS Method

38 What is the method? Footprint and calibration data Ascending trends and high correlation ensures correctness of calibration gas as well as events timing in GC

39 What is the method? Uncertainty monitoring Uncertainty limit can be set to flag an alarm when limit is reached

40 What is the method? Last calibration data update monitoring When data is not updated it s an indication that GC calibration has failed

41 In a Nutshell

42 GCAS GC Validation Valve timing correctness Calibration gas correctness

43 GCAS GC Validation Valve timing correctness Calibration gas correctness Control chart

44 GCAS GC Validation Valve timing correctness Calibration gas correctness Control chart Uncertainty calculation

45 GCAS GC Validation Valve timing correctness Calibration gas correctness Control chart Uncertainty calculation Spot sampling checks

46 GCAS GC Validation Valve timing correctness Calibration gas correctness Control chart Uncertainty calculation Spot sampling checks Fully auditable comments

47 Issues in Analyzer System Pressure Let Down System GC RISK BASED Cal gas

48 Other Validation Method GC calculated density vs densitometer measured density GC calculated VOS vs USM measured VOS

49 ISO10723 vs GCAS The only health check / validation feature that s missing in GCAS is linearity determination Density or VOS comparison is additional set of validation that can be used ISO to determine GC linearity

50 CONCLUSION

51

52 Where the following conditions are met: Initial ISO has been done on well maintained GC

53 Where the following conditions are met: Initial ISO has been done on well maintained GC Actual measurement bias are within acceptable limit

54 Where the following conditions are met: Initial ISO has been done on well maintained GC Actual measurement bias are within acceptable limit GC proves to be reproducible throughout the year (low uncertainty)

55 When Do We Need to do ISO10723 Performance Test? DECC Guideline: risk-based analysis Error exposure if it s not being done Arguably, ISO should be done any time there s a major change in thermal conductivity property of detector

56 Considering all that Can the frequency of ISO be reduced? What would be the requirement to do that?

57 Thank You i-vigilant