Emissioni convogliate in atmosfera: Sistemi di monitoraggio in continuo delle emissioni SME

Transcription

1 Emissioni convogliate in atmosfera: Sistemi di monitoraggio in continuo delle emissioni SME Aspetti gestionali e verifiche periodiche (norma UNI EN 14181:2015) Walter Battaglia - Alessandro Migatta - Sandro Casagrande (Stazione Sperimentale del Vetro ScpA)

2 SUMMARY The presentation will take into consideration the following topics: 1. Description CEM Management a. CEMS Manual content 2. CEMS calibration procedures: a. D.Lgs.152/06 (IAR + linearity + characterization of the dust meter) b. UNI EN 14181: QAL1, QAL2, QAL3, AST Procedures 3. Differences between UNI EN 14181:2005 and 2015 edition a. General description of new edition 2015: I. Calibration functions II. Topics

3 CEMS management Audit and periodic checks Periodic maintenaince Management ELV exceeds and failures CEMS Management Annual Calibration and/or check (EN or D.Lgs. 152/06) Periodic automatic or/ manual calibration

4 CEMS management Audit (periodic checks) and reports Weekly automatic and/ manual calibration Annual Calibration and audit (EN 14181) Management of failures and exceeds the ELV Periodic maintenance

5 CEMS management: Manual of the CEMS The manual management of the CEMS must contain at least: 1. Description and requirements of the CEMS (QAL1) 2. CEMS calibration procedures: UNI EN (QAL1, QAL2, QAL3, AST) or D.Lgs.152/06 (IAR + linearity + characterization of the dust meter) criteria 3. Periodic CEMS audits, evaluation of calibration criteria (CEMS quality assurance) 4. Names and responsibilities of people involved in the CEMS management 5. Periodic maintenance of the CEMS description 6. Data acquisition system requirements, validation and processing mode, storage and modality of data transmission to the Competent Authority (CA) 7. The procedures agreed with the CA have to be implemented in case of Plant failure/ system failure of CEMS or portions of this in case of an ELV exceed 8. Alternative measures and timelines in case of unavailability of data from the CEMS 9. List of CEMS management procedures (Monitoring and check)

6 Quality Assurance Standard Procedures The CEMS quality assurance has to be guaranteed and checked by EN or by means calibration and checks according to D.Lgs. 152/06: CEMS CALIBRATION OR CHECK UNI EN QAL1 Selection of an appropriate CEMS (Certificate QAL1) QAL2 Installation and calibration of the CEMS and verifies if the CEMS meets the measurement uncertainty requirements, once installed. (Calibration function) QAL3 The ongoing quality control AST Regular checks of the calibration function QAL2 D.Lgs. 152/06 IAR Accuracy relative index Linearity check instrumental response Dust meter calibration Correlation determinination curve

7 Quality Assurance Standard D.Lgs. 152/06 Procedure The CEMS quality assurance is guaranteed according to D.Lgs. 152/06 (Annex VI, Part V): Relative Accuracy Index of direct measuring systems (Points and 4.4). The verification of accuracy of a measurement is performed by comparing the measurements IAR detected by the system under consideration (AMS) with the measurements taken in the same place or in the same area sampling by another measuring system used as a reference (SRM). The agreement between the two systems is evaluated, taking at least three measures of comparison, using the index of accuracy relative (IAR). Check instrumental response (Point 4.1): Regular checks edited by the plant operator, Linearity consist of periodic monitoring of the response of the entire measurement range of the individual analyzers, to be made at least annually. This type of check must be made even after maintenance interventions consequent to a failure of the analyzers. Correlation curve (Point 4.2.1): In case of in situ analyzers for the measurement of gas or Dust meter calibration dust, which provide a indirect measure of the concentration value, the calibration consists in determining the field of the correlation curve between the instrumental response (AMS) and the values supplied by a second manual or automatic system (SRM)

8 Quality Assurance Standard Procedures The CEMS quality assurance has to be guaranteed and checked by EN or by means calibration and checks according to D.Lgs. 152/06: CEMS CALIBRATION OR CHECK UNI EN QAL1 Selection of an appropriate CEMS (Certificate QAL1) QAL2 Installation and calibration of the CEMS and verifies if the CEMS meets the measurement uncertainty requirements, once installed. (Calibration function) QAL3 The ongoing quality control AST Regular checks of the calibration function QAL2

9 Quality Assurance Standard EN Procedures Proced ure Activity Priority Timescales of EN Procedures Responsibility QAL1 Selection of an appropriate CEMS (Certificate QAL1) Before an AMS can be installed on site Manufacturer QAL2 Installation and calibration of the CEMS and verifies if the CEMS meets the measurement uncertainty requirements, once installed Operator Within 6 months after installation of a new CEMS; At least every three/ five years depending on the (Laboratory) Plant; If a QAL3 evaluation demonstrates a need for a QAL2; If there is a significant changes, upgrades or repairs to the CEMS which will influence and change the results significantly; Whenever there is a significant change in plant operation which changes the emissions. QAL3 The ongoing quality control Continuously from installation. It is advisable to apply the QAL3 procedure before QAL2 tests Operator AST Regular checks of the calibration QAL2 Annually Operator (Laboratory)

10 Quality Assurance Standard EN Procedures EN14956; EN15267 EN14181 EN14181 Manufacturer Operator / Test House Operator / Test House

11 Continuous Monitoring System Dynamic approach The CEMS used as SRM is composed of: Gas: O2, CO, NOx Cooled probe for the extraction of the gaseous flow and cooler system equipped of filter. The gas samped is delivered to analyzers Temperatures Pressures Cooled probes Micromanometers Data Lab 1 acquisition unit AMS Calibration suction

12 Trend emissions values Analytical Method During the sampling in according to QAL2/AST procedures must be used the following method: n Measurements Data Method of analysis Principle of method 1 Stack temperature, velocity and EN ISO volume flow rate of the exhausts gases Discontinuous 2 Volume concentration of dry Oxygen EN 14789:2005 Continuous (Paramagnetic) 3 Carbon oxides conc. (CO) EN 15058:2006 Continuous (NDIR) 4 Oxides of Nitrogen (NOx) EN 14792:2005 Continuous (Chemiluminescence) 5 Sulfur Oxides (SO2) EN Discontinuous 6 Determination of the water vapour in EN ducts (H2O) Discontinuous

13 Procedures QAL2, AST: flow chart Functional test AST: Minimum 5 valid measurements in a day Parallel measurements with the SRM AST Data evaluation Calibration function of the AMS and its range of validity Calculation of variability Test of variability Reporting QAL2: Minimum 15 valid measurements spread over at least 3 days

14 UNI EN 14181:2015: Significant technical changes introduced The mains changes in the 2015 revision are: 1. The confidence intervals provided for ELV are now defined as MPU (Maximum permissible uncertainty) 2. The procedures of the QA and objectives apply to the daily ELV. 3. Functional checks QAL2 and AST have been uniformed 4. All QAL2/ AST must be conducted by a laboratory accredited ISO in its list testing is accredited for UNI EN The AMS measurement range can be chosen in such a way that fits better the value of the short term ELV 6. A new method has been added for those situations in which the concentrations of pollutants are very low and it is not possible check the performance of the AMS (they can be used materials reference in combination with data from the QAL2);

15 UNI EN 14181:2015: Significant technical changes introduced 6. In some circumstances is expected a reduced number of points for the QAL2 and methods of identification and reporting has changed outliers 7. And greater flexibility was introduced in the development of the cards control for the QAL3 8. The criteria to develop the functional tests and to process the QAL2 relatively peripheral parameters (O2 and water vapor) were modified; 9. They updated the references to standards for the certification of instruments (A to EN 15267) and for the localization of the measures (UNI EN 15259) have been update (. Annex J of the Standard shows the main changes present in the second revision

16 UNI EN 14181:2015: Significant technical changes introduced Same functional test for both procedures

17 UNI EN 14181:2015: Significant technical changes introduced Measurements importance of peripheral parameters 1 The influence of oxygen measurements error increases with its level of concentration 2 For humidity is possible to use theoretical values

18 UNI EN 14181:2015: Significant technical changes introduced 6.3 If calibrated AMS measured values for water vapor are available, these may be used to convert the SRM data to dry or wet basis. In case of wet abatement techniques with nearly costant water vapour concentration, conversion to dry or wet basis may be carried out using calculated water vapour values. 6.3 If the QAL2 is not the first QAL2 being carried out on the AMS, then an AST may be performed instead of a QAL2 provided that the SRM measured values obtained in the AST and at least 95% of the AMS measured values at standard conditions obtained since the last AST are less than the maximum permissible uncertainty specified e.g. in the relevant EU Directive

19 UNI EN 14181:2015: Significant technical changes introduced Requirements has been added that outliers in data sets shall be identified and reported. The EN doesn t mention the statistical method to identify the outliers in the data set. Some Labs use Huber test or a z score test. SSV: (Quick guide RM-QG14 Dealing with outliers in monitoring data) UK Environmental Agency

20 UNI EN 14181:2015: Significant technical changes introduced A new procedure for treatment of low level clusters has been added. The criterion for the identification of a cluster has been changed from 15% of ELV to the maximum permissible uncertainty. Criterion changed from 15%ELV to P.U A: (ysmax-ysmin) p(x) ELV The calibration function is decribed as: y= a+bxi+e B: (ysmax-ysmin) < p(x) ELV Ysmin 15%ELV Procedure C: Addition of two data pairs with CRM, zero and close to ELV C: (ysmax-ysmin) < p(x) ELV Ysmin < 15%ELV

21 UNI EN 14181:2015: Significant technical changes introduced 6.5 A minimum upper limit of the valid calibration range of 20% of ELV has been added 6.5 Treatment of exceedances of the valid calibration range in case of discontinuos plant operation or plant failures has been added. Last 168 operational hours (representing one week in operation)

22 UNI EN 14181:2015: Significant technical changes introduced 7.3 Choosing control chart. Any type of manual or automated control chart, which allows separate or combined determination of drift and precision may be used threee examples of control charts (Shewhart, EMWA and CUSUM) are described in Annex C. An alternative to an external control chart is to use built-in procedures. CEMS QAL3 CHECK built-in procedures CEMS internal checks to compensate for drift and to warn for instrument problems Zero and span checks according to QAL1 (EN ) Data checks shall be available to the operators Describe in detail the built-in procedure CEMS has to be able to record any for a time period longer than one year (AST, QAL2) Describe how to respond to exceeding of control chart limits Alarms to the operators have to be output when the control chart limit are exceeded

23 UNI EN 14181:2015: quality assurance The standard EN guarantees the quality assurance of automated measuring system (CEMS), but it assumes that the standards reference methods (SRM) have not BIAS and that each variability observed is due only to AMS uncertainty. In particular the EN standard evaluates the variability of experimental results but does not include any test to the BIAS. CEMS CALIBRATION OR CHECK QAL1 Selection of an appropriate CEMS (Certificate QAL1) QAL2 Installation and calibration of the CEMS and verifies if the CEMS meets the measurement uncertainty requirements, once installed. (Calibration function) QAL3 AST The ongoing quality control Regular checks of QAL2 calibration function SRM Is the SRM correct and free of uncertainty? SRM check Procedure

24 SRM Check Procedure The purpose of the procedure is to verify the performance requirements of the SRM system and ensure the quality of the same in time, in order to define and reduce to a minimum the uncertainty. Listed below are the main checks carried out: 1. Check if SRM is QAL1 certificated; 2. Maintenance of instrumental linearity according to EN 14181; 3. During the QAL2/ AST tests: calibration protocol and functional test QAL1 Verifica linearità Test funzionali

25 Thank you for your kind attention!