On the assessmement of pollutant emissions: the role of

IN DEGREE PROJECT MECHANICAL ENGINEERING,SECOND CYCLE, 30 CREDITS

, STOCKHOLM SWEDEN 2016

On the assessmement of pollutant emissions: the role of flue gas flow rate measurement

Critical review and industrial feedback

JULIETTE CHATEL

KTH ROYAL INSTITUTE OF TECHNOLOGYSCHOOL OF INDUSTRIAL ENGINEERING AND MANAGEMENT

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Master of Science Thesis EGI-2016-106MSC

On the assessment of pollutant emissions: the role of flue gas flow rate measurement

Critical review and industrial feedback

Juliette Chatel

Approved

2016-22-12

Examiner

Per Lundqvist

Supervisor

Fabian Levihn Commissioner

ALCIMED

Contact person

Ronan Lucas

Abstract From a bottom-up perspective, the assessment of flow rate of stack flue gases is crucial being the very first brick of the calculation. With the concentration of pollutant, it gives access to the amount of pollutant released in the atmosphere. Nevertheless, flow rate measurement has not been well-framed and can be poorly controlled, leading to large uncertainties. The recent launch of the European Standard EN 16 911 has enlighten the lack of expertise concerning the flow rate assessment in the industry. That is why RECORD, the project sponsor, conscious of the possible lack of expertise and the possible unreliability of the measurement is willing to understand the requirements; theoretical, technical and regulatory; for a reliable pollutant emissions measurement in accordance with the EU regulation in the field of waste treatment and incineration.

Thus, this study offers the theoretical, operational and regulatory keys to realize a reliable flow rate measurement. 9 methods are identified for stack flue gases flow rate measurement. For each of these methods an ID-card, based on bibliographical researches, supplier’s interviews and representatives of the industry’s feedbacks, has been built containing information required for a reliable measurement. This thesis will contribute to a report that will offers all the keys for a reliable velocity/flow rate measurement in the waste treatment (domestic waste incineration mainly but it can also be useful in every industry that releases flue gas in the atmosphere: chemistry, steel manufacture, etc.).

Moreover, this study proposes an analysis of the European Standard related to flow rate measurement in the industry and enlightens the key information related to these standards for an industrial operator.

Finally, in relation with the complete report published on the RECORD website, a comparison tool of the 9 technologies is created to guide the industrial in their flow rate measurement. Once the best technology has been selected thanks to the comparison tool, the ID-card gives the key to realize a reliable measurement with the selected method. Finally, the theoretical part and the standard analysis have to be used as a frame for all the technologies.

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Table of Contents Abstract ........................................................................................................................................................................... 2

Foreword ........................................................................................................................................................................ 6

1 Context and problem formulation..................................................................................................................... 8

1.1 Background .................................................................................................................................................. 8

1.2 Problem formulation ................................................................................................................................10

1.3 Purpose and research questions ..............................................................................................................11

1.4 Expected contribution ..............................................................................................................................11

1.5 Disposition .................................................................................................................................................11

2 Methodology .......................................................................................................................................................14

2.1 State of the art of the techniques and devices for flue gases flow rate measurement ....................14

2.2 Review of current standards ....................................................................................................................17

2.3 Collection and analysis of industrial feedbacks on flow rate measurement ....................................17

2.4 Planning of the study ................................................................................................................................17

2.5 Discussions on the methodology ...........................................................................................................17

3 Results ..................................................................................................................................................................20

3.1 Theoretical and operational reminders on flow rate and velocity measurement of canalized flows 20

3.2 Technologies identification .....................................................................................................................32

3.3 Review of the technologies ......................................................................................................................34

3.4 Technology comparison ...........................................................................................................................40

3.5 European standards analysis and synthesis ...........................................................................................42

4 Conclusions .........................................................................................................................................................44

5 APPENDICES ...................................................................................................................................................46

5.1 APPENDIX 1: Techniques ID card template .....................................................................................46

5.2 APPENDIX 2: Uncertainty calculation for the QAL1 certification of a Pitot tube manufactured by PCME Ltd. (TUV Rheinland, 2016) ..............................................................................................................52

5.3 APPENDIX 3: QAL 1 certificated flow rate/velocity products (MCerts; SIRA certification; CSA group, 2016) (TUV Rheinland, 2016) ........................................................................................................54

Acknowledgements .....................................................................................................................................................56

List of figures ...............................................................................................................................................................58

References .....................................................................................................................................................................60

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Foreword

The following report is the result of several months of work in the Energy and Environment department of the innovation consulting company ALCIMED. Created in 1993 in Paris, it now employs 200 consultants all around the world divided in the following different business units: healthcare industry, life science, agribusiness, public policies, chemicals and materials and finally energy, environment and mobility. The Energy and Environment team work with companies involved in renewable energies, oil & gas, power, water, waste, energy efficiency, energy management, industrial gases, tertiary and nuclear industries. Missions type are various: new market approaches (e.g. designing new services, designing innovative business models, seizing opportunities in adjacent markets, implementing unexpected partnerships, motivating communities of customers), technological developments (e.g. the impact of new technologies, analyzing the actions of market leaders and innovators, building an ecosystem of technology partnerships, drawing up an R&D roadmap) or simply to establish positioning on new issues (e.g. Industrial Internet of Things, circular economy, sharing, blockchain…).

This project was conducted for the French collaborative network RECORD gathering public and private environmental organizations. The main objective of this collaboration is the funding and the realization of studies and researches in the field of waste (domestic and industrial) and industrial pollution. Their areas of study are: the evaluation and the characterization of waste and pollution, the management of waste and contaminated sites, the evaluation of the impacts on health and on natural environment and the development and integration of knowledge from the field of social sciences.

The results of this work will be published in a completed report titled – Mesurages de vitesses et débits gazeux en vue de déterminer des flux de polluants canalisés. Revue critique et retours d’expérience1. This document will be released in the first months of 2017 on the RECORD website2 and will be accessible by everyone. The following article describes the work and the discussions encountered during the realization of this study. Some results cannot be found in this thesis but in the report on the RECORD report due to confidentially and properties reasons. Nevertheless, links to this report have been added to the section of the report.

The project manager, Mr. Lucas supervised, challenged and guided me during the work. A technical expertise especially in the field of European Standards was provided by the INERIS – National Institute of Industrial environment and risk.

NB – Due to confidentiality issues towards the ALCIMED Company, some data will not be communicated in this report.

1 In French on the website – The assessment of pollutant emissions: the role of flue gases flow measurement. Critical review and industrial feedbacks 2 The final report is available here: http://www.record-net.org/reports

http://www.alcimed.com/en/saveLang___en/

http://www.record-net.org/

http://www.record-net.org/reports

http://www.ineris.fr/en


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1 Context and problem formulation This chapter introduces the key issues of pollutants emissions assessment with the crucial role of flow rate and velocity measurement in the industry, which can lead to important uncertainties and mistakes if the good practices of measurement are not well implemented.

1.1 Background

1.1.1 GHG emissions reduction: a compulsory step for climate change mitigation

With more than 15 755 million tons of CO2eq released in 2012 by the OECD countries (OECD, 2016), the CO2 emissions and more globally the Green House Gases emissions are at the heart of the global warming concerns. A scientific consensus has now emerged to link the GHG emissions to the global rise of temperature and its dramatic consequences on climate change.

1.1.1.1 GHG emissions from a top-down perspective

These scientific publications have raised awareness and have led to political actions, with the Kyoto protocol at first followed by the recent COP 21 and 22. In all of these agreements, the mitigation of states emissions are crucial and debated issues: 188 countries are committed to reduce their emissions to limit global warming to 2°C between now and 2100. This target can be reached by reducing the GHG emissions by 40-70% by 2050 and the carbon neutrality needs to be achieved by the end of the century (COP 21, 2015).

To respect these commitments, actions have to take place at the origin of the GHG emissions which are described in the following chart:

Figure 1: Global mean surface temperature increase as a function of cumulative total global carbon dioxide (CO2) emissions from various lines of evidence, source: (IPCC, 2014)

Figure 1: Time series of global annual change in mean surface temperature for the 1900–2300 period (relative to 1986–2005) from Coupled Model Intercomparison Project Phase 5 (CMIP5) concentration-driven experiments, Source: (IPCC, 2014)

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Figure 2: Total anthropogenic greenhouse gas (GHG) emissions by economic sector (gigatons of CO2- equivalent per year, GtCO2-eq/yr) from economic sectors in 2010, source: (IPCC, 2014)

Thus, the direct emissions represent more than half of the global GHG emissions, and more than half of these are from industry. Thus, flue gases released in the industry (post-combustion mainly) represents an important share of the GHG emissions. This enlightens the importance of GHG evaluation in the industry releasing stack flue gases: gases released in the waste treatment industry are mainly composed of CO2, O2, H2O and N2 (IVRY PARIS XIII, 2013).

1.1.1.2 A need for trustful GHG emissions measurements

To mitigate the direct emissions, a carbon market has been implemented (European Comission - Climate Action, 2016) on the principle “polluters pays”: a GHG emissions threshold is delivered to industries releasing greenhouse gases. Companies that have emitted less than expected can sell CO2 quotas and those who exceed their threshold have to buy CO2 quotas or right to pollute. This implies that GHG emissions have to be precisely measured to have a trustful system. Besides, this is not the only reason for a precise and trustful measurement: many countries have implemented, national or supranational in the case of European Union, GHG emissions statements. The monitoring of the emission and the realization of right and reliable measures are crucial to respect their political commitments.

1.1.1.3 GHG emissions from a bottom-up perspective: the current situation of GHG emission measurements in the industry

As it has been underlined in the section above, the GHG emissions evaluation is crucial for each emitted entity. The mass of GHG gases; carbon dioxide CO2, methane CH4, nitrous oxide N2O, fluorinated gases; and also substances (for these last ones are not GHG but are important for environmental pollution)possibly regulated for environmental and health reasons such as heavy metals have to be known for the reasons explained above.

Currently, in Europe at least, industry has to declare their emissions in terms of pollutants concentration in mg/Nm3 (3) (FNADE, 2006). Yet, this concentration value cannot give access to the amount of pollutants emitted during a period of time.

3 The Nm3 are referring to standard conditions: the pressure is taken at 1 013 hPa and the temperature at 0°C. Cf. section 3.

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The concentration level can only provide threshold below which the local impacts on the environment and health are considered low. Nevertheless, it is not sufficient to determine accurately the amount of GHG released during a time lapse.

1.1.1.4 The need for flow rate or velocity measurements

The evaluation of yearly pollutant emissions requires the flow rate or the velocity of the flue gases emissions in Nm3 per unit of time.

1.1.1.5 The lack of framework concerning the flow rate measurement

As it has been enlighten before, currently the industry master and monitor the concentration measurements, which are well standardized and normed, whereas the flow rate measurements can, in some cases, be inaccurate (local measurements, non-established flow, non-symmetrical flow, etc.) and can cause reliability issues (charged fluid, calibration defects, etc.) if the good practices are not fully and well-implemented. Suppliers and experts4, interviewed during the study, agree that the measurement can be, in some cases, poorly controlled (influence parameters unknown, installation issues, large uncertainties, etc.). Indeed, when local regulations (such as prefectural order-decree) do not impose the flow rate measurement and the reliability control, the measurement can be up to 20% inaccurate, implying 20% of uncertainties on the pollutant emissions.

1.1.1.6 EN 16 911: a new standard to regulate the flue gases flow rate measurement in the industry

This measurement has been recently regulated in Europe with the publication of a new European Standard, the EN 16 911, describing and regulating the performances, the installation, the calibration and the use of flow rate or velocity AMS (Automatic Measurement System)5. This recent publication of the EN 16911 (entering in effect in 2017) is still debated and will come into effect in the next months.

1.2 Problem formulation The EN 16911 has launched the debate on flow rate measurement in flue gases and has enlightened the possible lack of knowledge and expertise on this measurement, which is a vital

4 Experts interviewed and reports on the subjects (ROBINSON) 5 A similar standard, the EN 14 181 were already implemented concerning the system measuring the concentration (the gases analyzers or dust monitors).

Figure 3: The role of flow rate measurements in the assessment of pollutant emission

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value to determine pollutant emissions yet. Actually, as figure 4 illustrates, the flow rate quantity is crucial to determine the amount of pollutant emitted during a period of time.

1.3 Purpose and research questions The issue of pollutants emission, and as it is emphasized in the previous paragraph, is particularly crucial in the waste treatment industry where flue gases are extremely framed and where multiple treatments are applied (IVRY PARIS XIII, 2013) (Urban community, 2007) before the release in the air. That is why RECORD, conscious of the lack of expertise and of a complete, simple guiding tool, eagers to understand the requirements; theoretical, technical and regulatory; for a reliable pollutant emissions measurement in accordance with the EU regulation in the field of waste treatment and incineration. Thus, this thesis will contribute to a report that will offer all the keys for a reliable velocity/flow rate measurement in the waste treatment (domestic waste incineration mainly but it can also be useful in every industry that releases flue gas in the atmosphere: chemistry, steel manufacture, etc.). Until now, no report are existing to guide the flowrate/velocity measurement in the industry.

The following research questions and sub-questions have structured the project approach:

• RQ 1: How can a flow rate measurement of flue gases be reliable? • Sub-question 1.1: What are the theoretical requirement, for an industrial operator, that

can impact the flow rate measurement reliability and accuracy? • Sub-question 1.2: How to choose the right instrument between the different existing

technologies and on which criteria, for a reliable flow rate measurement? • Sub-question 1.3: How is the measurement carried-out on site, are there any best

practices emerging among the industries?

• RQ 2: How to apply to European Standard on the flue gases flow rate assessment?

1.4 Expected contribution The purpose of the study is to provide a guiding tool for waste treatment (mainly domestic) industries regarding the flow rate measurement with the theoretical, the technical and the regulatory knowledge for a good, reliable and trustful emissions assessment. The final results will be presented in front of the RECORD steering committee, composed of experts and decision-makers of waste treatment leading company, in January 2017. After the approval of the RECORD members, the deliverables will be published on the RECORD website and broadcasted among the members of RECORD6.

1.5 Disposition The deliverable published on the RECORD website follows the disposition below which is also the disposition of this report7:

1- Context and problem formulation - This chapter introduces the key issues of pollutants emissions assessment with the crucial role of flow rate and velocity measurement in the industry, which can lead to important uncertainties and mistakes if the good practices of measurement are not well implemented.

2- Methodology – This section underlines the objectives of the study, the expected results and the methodology used to reach them. The study has been conducted in three main steps: a literature review with multiple types of sources combined with flow rate devices suppliers interviews with the objective to realize a state of the art of the existing

6 http://www.record-net.org/members 7 In this report, the results part is not fully integrated due to confidential reasons. Nevertheless, they could be found on the RECORD website once the study is published.

http://www.record-net.org/members

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available techniques for gas flow rate measurement, an analysis and a synthesis of the European standards and a collection of interviews of representative of the industry to gather feedbacks on the flow rate measurement in industries.

3- Results – The results section is organized in five main parts described below.

a. Theoretical and operational reminders on flow rate and velocity measurement of canalized flows – This section provides a short fluid mechanics theoretical description with the perspective to be usable at an operational level. The objective is to guide the operators to reliable measurements, explains and illustrates the basics of the measurements theories (influence of specific parameters, installation conditions, uncertainties parameters, etc.). In this section, the important messages from the standards are also included to make the standard key information practical and usable for industry.

b. Technologies identification – During the bibliographic researches and the different interviews

conducted, 18 technologies have been identified for flow rate/velocity evaluation of gases. Out of theses 18 methods, only nine technologies have been selected for flue gases flow rate measurement in the industry. This section explains the reasons of this selection and lists the available and usable technologies.

c. Review of the technologies – This section is composed of the 9 technologies descriptions. For each technology, an “ID-card” has been created describing: the principle of the measurement, the installation conditions, the benefits vs. the drawbacks of the solution, the main fields of application and typical case-studies if available, the diffusion rate of the solution in the industry, the operating condition of the technology (type of fluid, measurement ranges), the performances of the method, the costs (purchasing and operational) and finally the main suppliers. These ID-cards are a synthesis of the literature review, the suppliers’ and the industrial users’ interviews. The objective is to build a synthesis and practical comparison tool between the different technologies and to underline the correct and proper usage of the method to obtain a reliable and trustable measure. Besides, the terms and the notions used in the ID-cards are described, explained and illustrated. They are also linked and underlined with best practices and vigilance points - that have to be kept in mind – gathered during the interviews of industrial users and suppliers.

d. Technology comparison – This section provides a comparison tool for the industries. Different

criteria have been used related to the type of fluid, the environment of the measurement, the cost, etc.

e. European Standard analysis and synthesis – This section enlightens notions and important issues that can be found in the European standards related to air emission monitoring: the EN 15 259, 14 181, 15 267 and the last released the EN 16 911that will be implemented next year, in 2017.

4- Conclusions – This part concludes the work presented, underlines the answers provided to the researches

questions, the impact on the study and also enlightens knowledge gathered during the master thesis realization at Alcimed.

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2 Methodology This section underlines the objectives of the study, the expected results and the methodology used to reach them. The study has been conducted in three main steps:

1. a literature review with multiple types of sources combined with flow rate devices suppliers interviews with the objective to realize a state of the art of the existing available techniques for gas flow rate measurement

2. an analysis and a synthesis of the European standards 3. a collection of interviews with representatives of the industry to gather feedbacks on the flow rate measurement

in industries.

The study has followed three main steps with dedicated means for each of them:

It has been decided during the first steering committee that the work will also include flow rate measurement techniques for:

• the measurement of flow rate of stack flue gases with the objective to estimate the emissions and to be in conformity with the regulation,

• the measurement of process gases in the incinerator plant and biogas with the objective to assure control of the process.

2.1 State of the art of the techniques and devices for flue gases flow rate measurement

2.1.1 Bibliographic researches

The bibliographic researches aimed to identify the available techniques and to characterize them, to understand the features of flow rate measurement and finally to gather best practices. To reach these objectives, sources from diverse nature have been used: academic supports, specialized media, scientific publications identified thanks to specialized databases – SCOPUS, SCIENCE DIRECT &

Figure 4: Methodology of the study - Objectives & means implemented

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TECHNIQUES DE L’INGENIEUR, MSc and PhD works, licenses database, publications from public institutional organisms, social media (Twitter8 and LinkedIn work group9), websites of flow rate solution supplier.

The main sources are listed and classified below:

8 The Twitter researches have allowed finding the magazine Flow Control. 9 The LinkedIn groups have helped during the state-of-the-art to check if no technology were forgotten and during the validation of the benefits/drawbacks for each technology. 10 Techniques de l’ingénieur, Engineering techniques are a reference database in engineering field: http://www.techniques-ingenieur.fr/.

Academic supports Teaching supports in fluid mechanics courses Bachelor and Masters level (COUFFIGNAL BTS CIA) (GATT, 2006) (MARCOUX, 2016) (SENGUPTA) (MOISY, 2014)

Specialized media Flow control magazine (WYATT, 2013)

Scientific publications 27 relevant publications counted since 2011 on the SCOPUS database

7 relevant publications on specific flow rate measurement techniques on the SCIENCE DIRECT database

5 relevant articles in the Techniques de l’ingénieur 10 (TI - Techniques de l'ingénieur): Optic velocimetry (BOUTIER, et al., 1998), Local velocity measurements in a fluid (DUPRIEZ, et al., 2013), Volumetric flow rate measurement devices (DELLA BELLA, 2007), Choice of a flowmeter (SIGONNEZ, 2006), Temperature sensors (ROGEZ, et al., 2010)

PhD thesis (LE GLEAU, 2012) (RIGAL, 2012)

MSc thesis (BENHICOU, 2003) (CHERIGUI, 2003)

Specialized literature (BOUTIER, 2012)

1 interview realized with the Scientific Director of RECORD, Department Head of Industrial Processes for the University of Technology of Compiègne (UTC)

Patents 300 patents reviewed on the European patent office database (EPO - European Patent Office , 2016) with a worldwide scope, using the key words: “flow meter” OR “velocity fluid” NOT(electromagnetic OR ultrasonic), from 2012 to 2016

Institutional publications United States: Environmental Protection Agency (US Environnement

http://www.techniques-ingenieur.fr/

http://www.techniques-ingenieur.fr/

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11 « BREF or ‘BAT reference document’ means a document, resulting from the exchange of information organized pursuant to Article 13 of Directive 2010/75/EU, drawn up for defined activities and describing, in particular, applied techniques, present emissions and consumption levels, techniques considered for the determination of best available techniques as well as BAT conclusions and any emerging techniques, giving special consideration to the criteria listed in Annex III to Directive 2010/75/EU. A similar definition was applicable under the IPPC Directive (2008/1/EC). » (JRC - Joint Reasearch Center, 2016) 12 ADEME – National Agency for the Environment and the Energy Control, France 13 CETIAT is a study, testing and calibration laboratory in the fields of aerodynamics and fluid mechanics, heat sciences and acoustics. 14 INERIS – National Institute of Industrial environment and risks.

Protection Agency , 2016), NIST – National Institute of Standards and Technology, US Department of Commerce (NIST, 2016), Laboratory report (ELI LILLY & TIPPECANOE LAB, 2006)

Europe

European collaboration: VGB European Working group emission monitoring (GRAHAM, et al., 2012), European Committee for Standardization (UE) (CEN - European Committe for Standardization, 2011), European - Best Available Techniques11: Monitoring of emissions from Industrial Emission Directive-installations (JRC Joint Reasearch center, 2013), Waste incineration (European IPPC Bureau - Integrated Pollution Prevention and Control, 2006)

UK: National Physical Laboratory (ROBINSON), National Measurement Systems (TUV Nel for the National Measurement Office, 2009)

Netherlands: NL Agency (InfoMil, 2012)

France: Ademe12, CETIAT13 (CETIAT, ADEME & DGCIS, 2014) (RIQUIER, 2013), INERIS14 (POULLEAU, 2014) (CETIAT, INERIS & LNE, 2004)

Website and documentation of measurements solution suppliers

ABB, Codel international, Cole Parmer, Dantec, Delta fluid, Dr. Födish, Durag, Fluid Component international, Fuji Electrics, Hontzsch, Horiba, Itron, Kurz, OSI, OTI industries, PCME, Sick, Siemens, SKI, TSI, Vortek, Yokogawa

Social media Workgroup LinkedIn (Continuous Emissions Monitoring Professionals, Air emissions monitoring, flow measurement, Flue gas know how, Metrology and Test measurement, Waste management and recycling professionals, Instrumentation technicians group), Twitter (Flowmeters supplier accounts)

Figure 5: Main sources used during the literature review

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The researches have been conducted both in English and in French.

2.1.2 Flowmeter supplier interviews

In order to complete the technical information gathered on their website and documentations, 14 phone interviews have been conducted with solutions suppliers located in Europe (France, UK, Germany, Spain, Italy and the Netherlands) and in North America. Their knowledge was precious to truly understand their technology but also to identify best practices related to it. Moreover, the discussions have also allowed identifying the key selection criteria related to flow rate sensors.

2.2 Review of current standards This phase has included an analysis and a synthesis of the European Air Emission standards: EN 16 91115, 14 18116, 15 25917, 15 26718 related to devices, measurement methods, the qualification and the certification of the devices used, as well as their calibration and their performances requirements (such as uncertainty, reproducibility and resolution). Moreover, the work has included a study of the two certifications institutes of air emission devices: TUV Rheinland (TUV Rheinland, 2016), MCerts (MCerts; SIRA certification; CSA group, 2016).

Finally, for this part, multiple exchanges were made with the INERIS – National Institute of Industrial environment and risk – with the dedicated department of standards. These discussions have led to the choice of the 4 standards named earlier.

2.3 Collection and analysis of industrial feedbacks on flow rate measurement 7 interviews have been conducted with representative of the industry (metrology operators and engineers, environment and process engineers, project managers, R&D measurement engineers, etc.) operating in biogas production and transport, in domestic waste incineration, in hazardous waste incineration or in chemical industry located in Europe (France, Germany and Bulgaria). The objectives were to understand their measurement context (type of gases, humidity content, temperature, straight lengths, inner pipe diameter, type of flow, etc.), the solution they use, the reason why they have chosen this solution and the problems encountered – to underline the possible correlation between a characteristic of the measurement environment and the choice of a specific device but also to identify best practices.

2.4 Planning of the study The study has begun on the 16th of June with a launch meeting with the ALCIMED team and the steering committee of RECORD composed of 10 persons followed by two steering committee meetings in mid-September and mid-November. A final meeting is planned for January 2017/

During these meetings, intermediary results were presented and the scope of the study was modified with the willing to introduce the study of biogas measurement (during the production on the waste site, the transports and finally before the engines or the boilers) for instance.

2.5 Discussions on the methodology The methodology used to conduct this study is robust meaning that the results are not affected by small variations. Actually, the diversity (geographical, nature of source, interviews of both suppliers and users) of the sources has allowed validating the information. If one piece of information was contradictory to another one, it has been challenged by other interviews and researches. For each of the nine selected 15EN 16 911 – Stationary source emissions -- Manual and automatic determination of velocity and volume flow rate in ducts (EN16911, 2016) 16 EN 14 181 – Stationary emissions – Quality assurance of Automatic Measuring Systems (EN14181, 2014) 17 EN 15 259 – Air quality - stationary source emissions measurement. Requirements for measurement sections and sites and for the measurement objective, plan and report (EN15259, 2015) 18 EN 15 267 – Air quality – Certification of Automatic Measurement System (EN15267, 2015)

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technology but also to challenge the non-relevant nature of the nine remaining, multiple suppliers’ interviews have been made (the interviews were conducted at different level: from the sales representative, to the R&D team through the product manager). Moreover, in order to challenge technology comparison, suppliers offering several techniques from different manufacturer19. They were able to offer neutrality in front of the technology benefit/drawbacks and performances.

Besides, it was very interesting to have feedbacks of industrial users for the lesser known technics to balance and challenge the information from suppliers that tend to highlight only the benefits of their solution. They were chosen in order to have the wider points of view on the different technologies. Researches have been conducted before among the suppliers to have a list of their users or of their installation sites. When their answers were negative, researches have been made on LinkedIn and on the internet to look for case studies and possible users contacts. These researches have led to 7 interviews covering almost all the technology19. Case-studies or articles in magazines have completed the lack of information for the few technologies without interviews.

This challenge of data and on the choice of the difference criteria of the ID-cards (Cf. 3.3.1.1) between the different sources has also allowed validating the methodology.

One of the other possible weaknesses of the methodology was to forget one technology during the state-of-the-art phase. That is why the researches have been extended to patents (more than 300 patents examined from the last 4 years) and the two databases for scientific publication (164 publications reviewed on the Scopus database researches). Moreover, the technology list has been validated with experts from the RECORD scientific research direction and from the INERIS. Finally, Twitter and questions asked on specialized working group on LinkedIn: Continuous Emissions Monitoring Professionals, Air emissions monitoring, flow measurement, Flue gas know how, Metrology and Test measurement, Waste management and recycling professionals, Instrumentation technicians group have allowed to validated the list.

19 The name or brand interviewed cannot be write here due to confidentiality reason.

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3 Results

3.1 Theoretical and operational reminders on flow rate and velocity measurement of canalized flows

This section provides a short fluid mechanics theoretical description with the perspective to be usable at an operational level. The objective is to guide the operators to reliable measurements, explains and illustrates the basics of the measurements theories (influence of specific parameters, installation conditions, uncertainties parameters, etc.). In this section, the important messages from the standards are also included to make the standard key information practical and usable for industry.

In first words, it is worth recalling the use of normal conditions for temperature and pressure (noted N in front of units or X0 for physical quantities) in the industry. They are measurement conditions for which temperature and pressure are fixed, respectively at 0°C (T0 = 273 K) and at atmospheric pressure (P0 = 1.013 105 Pa). Thus, the flow rate will be expressed in Nm3/h and not in m3/h.

3.1.1 Essentials of fluid mechanics

In this section, the fundamental principles of fluid mechanics related to flow rate measurement are recalled. The influence of different physical parameters between them, especially with flow rate, is also underlined. Moreover, when it is useful references to best practices found in standards are also highlighted.

3.1.1.1 Equation-of-state for gases

Ideal Gas law gives the relation that links the temperature of the gas T, its pressure P, its volume V and its particles number n:

PV = nRT

Where P is expressed in Pa, V in m3, n in mol, T in Kelvin and finally R is the universal gas constant (R = 8.314 J/mol/K).

Generally, the quantity r is used, it is defined as: r = RM

where M is the molar weigh of the gas (expressed in g or kg per mol). Thus, equation (3.1) can be expressed under the following form:

P = ρ r T = ρ RM

T

Where ρ is the density of the gas (cf. 3.1.1.1.2).

3.1.1.1.1 Molar volume Vm

It is the volume occupied by one mole of gas, noted Vm.

From the equation (1), it can be deduced the following relation:

Vm = 0.0224 Nm3/mol

This value is valid regardless the type of gas.

3.1.1.1.2 Density ρ

It is the mass of one volumetric unit of gas, noted ρ, expressed in kg/m3.

It can be deduced from equation (3.1):

𝜌 = 𝑃𝑟𝑟

= 𝑃 𝑀𝑅𝑟

As it has been in the foreword of this section, multiple values are expressed under normal conditions for temperature and pressure, then, it is necessary to be able to translate the data measured under industrial conditions, called true conditions, of temperature and pressure (true value) under normal conditions.

(Eq. 3.1)

(Eq. 3.2)

(Eq. 3.3)

(Eq. 3.4)

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From equation (3.1), it can be deduced the following relation:

𝜌(𝑃,𝑟) = 𝜌0 �𝑃(𝑇)𝑃0� �𝑇

0

𝑇�

It is important to underline that the access to ρ0 requires the knowledge of the gas composition (O2, CO2, SO2, H2, etc. because it is rarely pure gases) and more especially the volumetric fraction of each of its components as well as their density. The density of the mix of gases is obtained by calculating the weighted average of each of the components:

𝜌(𝑃,𝑟) = 𝑃 𝑀𝑅𝑟

𝑜ù 𝑀 = 10−2�%𝑋 𝑀𝑋

Where %X is the content of the component X in the gas flow in volumetric percentages (also called volumetric fraction) on humid gas and Mx its molar volume (in kg/mol).

Usually, only the following species are taken into account: O2, CO2, H2O and N2 (that can be deduced from the other species contents: %𝑁2 = 100− (%𝑂2)− (%𝐶𝑂2)− (%𝐻2𝑂)). The molar volume M of the gas becomes then:

𝑀 = 10−5 (32 (%𝑂2) + 44 (%𝐶𝑂2) + 18 (%𝐻2𝑂) +

28 (100 − (%𝑂2) − (%𝐶𝑂2) − (%𝐻2𝑂))

Illustration: Influence of the temperature on the density ρ

For instance, for a gas composed only of air, with a change of the temperature from 120°C to 140°C, the density will decrease from 0.898 kg/m3 at 120°C to 0.854 kg/m3at 140°C. Thus, in that case, a raise of 17% of the temperature induces a decrease by 5% of the density.

Figure 6: Evolution of the density of gas composed of air in function of the temperature

Please note:

- The influence of the pressure and the temperature on the quantity ρ cannot be neglectable.

3.1.1.2 Gas flow rate

The volumetric flow is the flux of fluid which passes through a surface per unit time.

3.1.1.2.1 Volumetric flow rate

The volumetric flow rate links the velocity of the fluid to the section of the fluid flow.

It is expressed as:

𝑄𝑣 = < 𝑣 > 𝐴

00,20,40,60,8

11,21,4

0 50 100 150 200 250 300 350 400 450

Den

sity

(kg/

m3 )

Tmperature (°C)

(Eq. 3.5)

(Eq. 3.6)

(Eq. 3.7)

(Eq. 3.8)

-22-

Where <v> represents the mean output velocity in the cross-sectional area A.

The determination of the area A requires the use of the hydraulic diameter that allows to calculate the surface of any flat surface, it is defined as follow:

𝐷ℎ = 4 𝐴𝐿

Where A is the cross-sectional area and L the wetted perimeter, that is to say, the perimeter of the section that is in direct contact with the fluid (in our field of study, gases flows, it is always the total perimeter of the section).

Thus, it follows:

𝑄𝑣 = < 𝑣 > 𝜋 �𝐷ℎ2

�2

Please note:

- In the case of a circular pipe, Dh corresponds to the inner diameter of the pipe.

3.1.1.2.2 Mass flow rate

The mass flow rate is expressed in kg/h (or tons per hour) using the following relation:

�� = 𝜌0 𝑄𝑣0

Where Qv0 represents the volumetric flow rate under normal conditions, expressed in Nm3/h.

It has to be underlined that the mass flow rate follows the law of conservation:

�� = 𝜌0 𝑄𝑣0 = 𝜌(𝑃,𝑟) 𝑄𝑣(𝑃,𝑟)

It can be deduced from the previous equations that:

�� = 𝜌0 𝑄𝑣0 = 𝜌(𝑃,𝑟) 𝑄𝑣(𝑃,𝑟) = < 𝑣 > 𝑆 𝜌0 �𝑃(𝑟)𝑃0

� �𝑟0

𝑟�

The relation (3.13) illustrates that the mass flow rate is inversely proportional to the temperature.

Illustration: Influence of the temperature on the mass flow rate

For instance, for a gas only composed of air, at 120 °C, with a flow velocity of 10 m/s, flowing in a circular pipe with a hydraulic diameter of 1m, at atmospheric pressure, the mass flow rate is 7.05 kg/s that is to say 25.4 tons/h. The change of the temperature from 120 °C to 140°C decreases the mass flow rate by 5% (6.7 kg/s or 24.0 tons/h).

Figure 7: Evolution of the mass flow rate in function of the temperature

02468

1012

0 40 80 120 160 200 240 280 320 360 400

Mas

s flo

w ra

te (k

g/s)

Temperature (°C)

(Eq. 3.9)

(Eq. 3.10)

(Eq. 3.11)

(Eq. 3.12)

(Eq. 3.13)

-23-

A modification of the gas composition directly impacts the value of the density ρ0 of the fluid. The equation (3) illustrates the direct influence of the gas composition on the mass flow rate since it shows that these two parameters, the mass flow rate and the density of the fluid, are proportional.

Illustration: Influence of the gas composition of the mass flow rate

For instance, for a gas only composed of air, at 120 °C, with a flow velocity of 10 m/s, flowing in a circular pipe with a hydraulic diameter of 1m, at atmospheric pressure, the mass flow rate is 7.05 kg/s that is to say 25.4 tons/h. The raise of the density (and so of the gas composition Cf. 3.1.1.1.2) of 10% increases the mass flow rate by 10%.

Figure 8: Evolution of the mass flow rate in function of the density of the fluid

Please note:

- The volumetric flow rate is almost always expressed under true conditions; thus it is essential to use the value of the density ρ(P,T) under true conditions. To do so, the relation (2) will be used, requiring additional measurements of the temperature T and the pressure P. This is essential for a reliable measurement.

3.1.1.2.3 Volumetric flow rate under normal conditions on dry gas and in reference oxygen content

Besides, in many industrial sites, in order to be comparable, the volumetric flow rate is expressed under normal conditions but also on dry gas and at reference oxygen content (11% of O2). To do so, the following relation is used:

𝑄𝑣,𝑠𝑠𝑠,𝑂2 𝑟𝑠𝑟0 = 𝑄𝑣 𝑃

𝑃0 𝑇

0

𝑇 100−%𝐻2𝑂

100 20.9−%𝑂220.9−%𝑂2 𝑟𝑟𝑟

Where Qv is the volumetric flow rate under true conditions, P0 and T0 the pressure and temperature values under normal conditions, %H2O the humidity content of the gas, %O2 the oxygen content under true conditions and %O2 ref the reference oxygen content (expressed in volumetric percentage et often taken as 11%). (FNADE, 2006).

3.1.1.3 Flow regime typology

Two major flow regimes can be defined: the laminar and the turbulent regime. The Reynolds number (noted Re and without dimension) characterizes these regimes. It is defined as follow:

𝑅𝑅 = 𝐷ℎ < 𝑣 (𝑃,𝑟) >

𝜇(𝑃,𝑟) 𝜌(𝑃,𝑟)

Where μ represents the dynamic viscosity expressed in Pi (Poiseuille or Pa.s) and ρ its density (in kg/m3).

0

2

4

6

8

101

1,05 1,1

1,15 1,2

1,25 1,3

1,35 1,4

1,45 1,5

1,55 1,6

1,65 1,7Mas

s flo

w ra

te (k

g/s)

Density of the fluid(kg/m3)

(Eq. 3.14)

(Eq. 3.15)

-24-

3.1.1.3.1 Laminar regime: Re < 2100

A flow is said to be laminar when its Reynolds number is below 2100.

In front of this type of flow, it is important to underline that the velocity profile has the particular feature of having the maximum velocity (at the center of the section) corresponding to the double of the mean output velocity (used for the flow rate calculation). This characteristic induces frequent mistakes with punctual measurement techniques such as thermal mass flowmeter or mono-point Pitot tube.

Figure 9: Velocity profile in laminar flow regime

3.1.1.3.2 Turbulent regime: Re > 104

A flow is said to be turbulent when its Reynolds number is above 104.

This type of flow has a quite flat velocity profile. This regime induces less measurement mistakes since the velocity is near uniform with a value very close to the mean output velocity (except close to the walls with the boundary-layer phenomenon).

Illustration: Calculation of the Reynold number in the typical stack flue gases conditions

For instance, the case of an air flow at 120 °C, in a circular pipe of 1m of hydraulic diameter, with a velocity of 10 m/s, the Reynolds number is 39 104: the flow is turbulent.

Please note:

- In the case of a turbulent regime with a steady and developed velocity profile (Cf. figure 11), the point of the profile with a velocity value corresponding to the mean output velocity is located at 12% of the hydraulic diameter from the boundary pipe or at 25% of the radium (source: EN 16911-2).

- During the velocity measurement, it is crucial to know the flow regime in order to adapt the right location of the sensor for a correct measurement of the mean output velocity and so of the flow rate. Yet, for biogas or stack flue gases in waste treatment facilities, the flow regime is always turbulent since the Reynolds number is always equal or higher than 3,60 104 (Cf. 3.1.2.1: the calculations of the Reynolds number, in the more extreme conditions that could possibly lead to laminar flow, gives a Reynolds number of 3,60 104 ). This is the minimum value that can be found in the scope of this study and it remains higher than 104 which implies that the regime is always turbulent (>104).

<v>

Vmax = 2

<v>

Figure 10: Velocity profile in turbulent flow regime

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3.1.1.4 Flow regime typology

3.1.1.4.1 Entrance (or development) length for a steady flow

For a laminar regime, the length required to fully develop the velocity flow (symmetric, without gyrations and homogeny profile) can be estimated with the following correlation (MARCOUX, 2016):

𝐿𝑠 = 0.06 𝐷ℎ 𝑅𝑅

Figure 11: Length entrance for a laminar flow, source: Aerospatiale Department, Fluid mechanics course, University of Sidney

For a turbulent flow, the following correlation can be used (MARCOUX, 2016):

𝐿𝑠 = 0.63 𝐷ℎ 𝑅𝑅0.25

Thus, a flow can be turbulent and steady like the illustration below underlined:

Figure 12: Velocity profile of a steady and turbulent flow

Thus, it clearly appears that having a fully developed and steady profile it is necessary to have a certain straight length upstream and also downstream in order not to disrupt the flow.

Please note:

- For measurement instrument requiring a steady profile, the EN 16911-2 recommends a straight length of 25 Dh upstream the device and 5 Dh downstream it.

Figure 13: Straight length recommendation, EN 16911-2

(Eq. 3.16)

(Eq. 3.17)

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- Nevertheless, the supplier information should be taken into account. - Moreover, the results of the velocity profile cartographies performed for the pre-studies of the

standard EN 16 911-1 (QAL 2 measurements for the choice of the Automatic Measurement System for the flow rate measurement and the validation of the representativeness of the measurement point) and the EN 15259 (homogeneity measurement experiences for all the stationary air emission measurement systems) can reduce these straight lengths.

- Finally, the straight lengths can also vary according to the type of elements upstream (elbow, valve, etc.).

3.1.1.5 Flow rate calculation summary

1- To calculate the density of the fluid under true conditions ρ(P,T), it is necessary to: - have access to the gas composition (components and their volumetric fractions) then calculate

the density of the fluid under normal conditions ρ0 - measure the temperature T and the pressure P in the flow

- then use: ρ(P, T) = ρ0 �P(T)P0� �T

0

T�

2- To calculate the volumetric flow rate Qv, it is necessary to:

- measure with the most relevant technic (Cf. Technology comparison section) and at a representative point the velocity and assess the mean output velocity <v>

- determine the cross-sectional area A (thanks to the hydraulic diameter Dh) - then use: Qv = < v > A

3- If it is required20, to calculate the mass flow rate, the two parameters above are used:

m = ρ0 Qv0 = ρ(P, T)Qv(P, T)

4- Finally, the Volumetric flow rate under normal conditions on dry gas and at reference oxygen content:

Qv,sec,O2 ref0 = Qv

PP0

T0

T 100 − %H2O

100

20.9 − %O2

20.9 − %O2 ref

20 The mass flow rate can be required by intern industry process calculations but it can also be needed in the case of local regulation (local degree, national or regional regulations).

Figure 14: Illustration of the evolution of the velocity profile in presence of an elbow upstream, (COSA Xentaur Corporation; Dr. J. David Hailey, 2015)

(Eq. 3.14)

(Eq. 3.12)

(Eq. 3.10)

(Eq. 3.5)

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3.1.2 Flue gases: a compressible fluid

Generally, the hydraulic theory (liquid fluids theory) is the most known and used. Nevertheless, in the case of stack flue gases study, this theory reaches its limits: its treats incompressible fluids (with a constant density ρ) whereas it could be questioned for gas at elevated pressures.

3.1.2.1 Variation of dynamic viscosity of gases

Several relations are still valid, such as for instance the Reynolds number:

𝑅𝑅 = 𝐷ℎ 𝑣𝜇

𝜌 = 𝐷ℎ 𝐺𝜇

Nevertheless, the dynamic viscosity μ of gases varies according to the temperature: its value increases with it. Typically, for gases, the dynamic viscosity raises by 2 to 5 10 -8 PI by temperature unit T21. Thus, when the temperature raises, μ raises too, and so the value of the Reynolds number decreases. This means that the flow is less and less turbulent: the representativeness of the measurement point is jeopardized compromising the whole measurement value.

Illustration: Influence of the temperature on the Reynolds number

If we consider a gas composed of air, with a velocity of 10 m/s, flowing in a circular section with a diameter of 1m, for a change of temperature from 120°C to 140°C, its dynamic viscosity μ raises by 3.5% changing from 2,30.10-5 Pa.s to 2,38.10-5 Pa.s. Besides, its density decreases from 0.898 to 0.854 kg/m3.

21 The Sutherland Law links the dynamic viscosity to the temperature according to the following relation:

𝜇(𝑟) = 𝜇0 ∗ �𝑟𝑟0�3/2 𝑟0 + 𝑆

𝑟 + 𝑆

Where µ0 is µ(T0) and S is called the Sutherland temperature and is taken equal to 110.4 K in the case of air.

Figure 15: Flow rate assessment process

(Eq. 3.18)

(Eq. 3.19)

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Thus, its Reynolds number decreases from 390 103 to 358 103, which represents a decrease of 8% (taking into account the influence of the temperature on the density and on the dynamic viscosity). The flow remains in turbulent regime in that case even though the conditions are extreme from stack flue gases measurement.

If we consider the most extreme conditions that can be found in the scope of this study that could possibly make the flow laminar (and so influences the whole measurement process): with a temperature of 250°C, a velocity of 3m/s, a diameter of 0.5 m, the Reynolds number is 3.60 104: the flow remains in turbulent regime.

If we take the case of biogas (100% CH4) flowing in the circular pipe with a diameter of 80 mm, at 50°C, at 10 m/s, the Reynolds number is 4.35 104 which means the flow remains in turbulent regime.

Please note:

- The regime is always turbulent under the conditions found in stack flue gases in waste treatment facilities.

- The regime is always turbulent under the conditions found in biogas production and transport in waste treatment facilities.

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3.1.3 Pressure measurement

As it has been underlined before and as it appears in some flow rate measurement techniques, pressure measurement is a crucial point (Cf. 3.1.1.2.2).

Different types of devices can be used such as membranes with capacitive sensors, constraints gauges or piezo-electric devices.

Principle Type Subtype Characteristics

Column of liquid

Manometer in U-tube - Indicator - Low pressure

Manometer in inclined tube

- Very low pressure measurement - More accurate than U-tube

Strain Bourdon’s tube manometer

- Indicator - Can function as a differential pressure measurement

method (eg. Pitot tube)

Bellows gauge - Absolute pressure measurement device (until 25bars)

Diaphragm gauge Strain gauge load - Analogic signal delivered in function of the distortion of the gauge under pressure

- Temperature influence - The signal processing required by this technology is

complex and expensive.

Differential transformation

- Differential pressure measurement with the induces currents by the motion of the membrane between two chambers (with two pressures)

- Robust and accurate (>99%) - Not recommended for pressure with quick variation

of pressure (few Hz)

Capacitive gauge - The electrical capacity varies in function on the distortion of the diaphragm.

- Used for low pressure measurements - Very short response time

Piezo-electric Piezo-electric gauge - The load applied to the quartz generates a electric tension proportional the distortion of the solid.

- Very short response time - Low level of sensitivity (few mbars) - Cost-benefits for pressure > 100 mbar

Figure 16: Main pressure measurement methods

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3.1.4 Temperature measurement

As it has been underlined before and as it appears in some flow rate measurement techniques, the temperature measurement is a crucial point.

Different types of devices can be used: thermocouples with different materials (Cupper, Nickel, Chromium, Platine, etc.).

Principle Description Subtype Characteristics

Thermocouple

The operational principle of thermocouple is based on the Seebeck effect. When two metals are combined to make a close circuit and that the two ends of this circuit are at different temperature, a current is established when creates an electric tension that only depends of the nature of the metals and the temperature difference.

T : Cu / Cu-Ni

J : Fe / Cu-Ni

E : NI-Cr / Cu–Ni

K : Ni-Cr / Ni-Al

S et R: Pt-Rh / P

B : Pt –Rh / Pt – Rh

N : Ni-Cr-Si / Ni-Si

- For each type (T, J, E, K, S, R, B et N), the temperature range can vary from -270 to 1800 °C. The smaller range is for T-type with -270°C to 400°C.

- The main benefits of thermocouples are: a short response time and a compact design.

- Their main drawbacks are: non-linear response, a medium sensitivity, the need of a reference measurement for absolute temperature measures.

- Its price can varies from 20 to 100€.

Resistance thermometer

(RTD)

The measurement principle is based on the resistance variation of metals wires in function of temperature.

Metal resistor

Semiconductor (diodes included)

- Resistors are generally made of Platinum Pt (Pt100 probes)

- The temperature measurement range can vary from -250 to 630 °C.

- Its main benefits are: a high sensitivity, a time stability, a low measurement uncertainty (reproducibility Cf.3.3.1.2.1: 0.05-0.1°C, accuracy 0.15 +0.002T or +0.03 or +0.005T according to the classification A, B or C).

- Its main drawbacks are: a relatively long response time (depending on the parameters on the probe), a sensitivity to mechanic and thermal shocks.

- Its price is around 100€.

Figure 17: Main temperature measurement methods

Multiple velocity and flow rate measurement devices own their own temperature and pressure measurement device offering a completed integrated solution. The data are then transported to a multi variable transducer to calculate the needed data (Cf. 3.1.1.5): Q0v dry o2 ref or mass rate.

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3.1.5 Gas composition evaluation

The analysis of gas composition, realized thanks to the devices presented in the table below, gives access to the gas density ρ (Cf. 3.1.1.1.2), an essential data for the calculation of mass flow rate (Cf. Figure 15) but also for calibration of some velocity/flow rate measurement techniques (Cf. 3.3.1.2.3) (for instance in the case of Pitot tube, the method is based on differential pressure measurement. The velocity is obtained thanks to Bernoulli equation requiring the gas density ρ).

Techniques Sampling type NOx SO2 CO CO2 O2 NH3 HCl HF COVT

Absorption IR Extractive or in-situ • + •

EN 1505

8 SRM

• • • • •

IR Gas Filter Correlation (GFC)

Extractive or in-situ • • • • •

FTIR Extractive • • • • • • • Specific VOCs

Photo-acoustic spectrometry Extractive • • • • • • •

Tunable laser diode (TLD)

Extractive or in-situ • • • • • •

Absorption UV Extractive or in-situ • • •

Fluorescence UV Extractive • •

DOAS Extractive or in-situ • • • • • •

Chemiluminescence Extractive EN

14792 SRM

•

Flame ionization Extractive • EN 12619 SRM

Zircon probe In-situ •

Para magnetism Extractive EN

14789 SRM

•

Electrochemical Extractive • • • • • • • • Figure 18: Main methods of common gaseous components measurement (CHATAIN, et al., 2014)

The measurements are not always realized in real time; the flue gases can be sampled and analyzed later in laboratory.

But in the waste treatment industry, the devices measuring gas composition and velocity/flow rate are located at the end of the process. This process consists in incineration of waste and then treatment of the flue gases released during the combustion process. Even if the composition combustible (wastes) varies, the composition of the flue is quite constant thanks to the treatment of the flue gas that homogenizes its composition. The value of density is required at the calibration step of the velocity/ flow rate meter. An updated of the density is required when to high variation (usually supplier considering 10% of variation as a thresholds) of density are seen and can highly impact the value of the velocity (Cf. 3.3.1.2.4).

3.1.6 Conclusions

This theoretical part, based on fluid mechanics theory, has underlined the influence of temperature, pressure, gas composition and representativeness of the mean velocity on the assessment of velocity and flow rate. It answers the RQ 1.1.

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3.2 Technologies identification During the bibliographic researches and the different interviews conducted, 18 technologies have been identified for flow rate/velocity evaluation of gases. Out of theses 18 methods, only nine technologies have been selected for flue gases flow rate measurement in the industry. This section explains the reasons of this selection and lists the available and usable technologies.

3.2.1 Irrelevant methods

Among the 18 techniques identified22, 9 have been considered irrelevant in the scope of the study for different reasons such as pipe diameter range, flow rate measurement range, under development techniques or still reserved for laboratory uses (use of very high quality components, expensive or difficult to implement in the industry), technical properties unmet (conductivity for instance), inaccurate method (such as rotameter), calculation method, etc.

Nevertheless, a short ID-card has been realized for these methods containing the measurement principle, the main field of application (and the reasons why the method is irrelevant in the scope of the study) and finally the diffusion rate of the method in the industry (still in R&D, scientific and laboratory use, specified use in the industry, non-continuous method or based on measurement). 23 For instance, the Coriolis flow meter is used when accuracy is the top priority (commercial transaction for natural gas, optimization of industrial processes using expensive raw material as examples) and its price is very high (50 k€). This technology is so not suitable for the stack flue gas flow measurement.24

3.2.2 Selected techniques for the flue gases, biogas an process gas measurement

Nine methods have been selected and fully described25. Among well-known methods, such as Pitot tube, Ultrasound based on transit time ort hermal mass flowmeter, can be found and lesser-known ones because of their recent release or their more restrain market such as Laser Correlation (firstly developed for flare gas measurement in the Oil & Gas sector).

With the objective of creating a practical guide for industry, each of the 9 techniques has been characterized with the same template (Cf. APPENDIX 1) using the same criteria to make the comparison, and later the choice of instrument, easier and clearer.

22 Due to ownership reason, the lists of the 18 techniques can be found in the RECORD report here: http://www.record-net.org/reports in the section (D1) for the non-relevant techniques and in the section (D2) for the selected one. 23 Due to ownership reason, the ID-cards are found in the RECORD report here: http://www.record-net.org/reports in the section (APPENDIX 5). 24 The ID-card of the Coriolis flow meter can be found in the section (APPENDIX 5) in the RECORD report: http://www.record-net.org/reports. 25 Due to confidentiality reason, the ID-cards are found in the RECORD report here: http://www.record-net.org/reports in the section (E.2). Nevertheless, examples of the layout are presented in APPENDIX 1 for two technologies: the Pitot Tube and the Ultrasound velocimeter working with transit time.







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3.3 Review of the technologies This section is composed of the 9 technology descriptions. For each technology, an “ID-card” has been created describing: the principle of the measurement, the installation conditions, the benefits vs. the drawbacks of the solution, the main fields of application and typical case-studies if available, the diffusion rate of the solution in the industry, the operating condition of the technology (type of fluid, measurement ranges), the performances of the method, the costs (purchasing and operational) and finally the main suppliers. These ID-cards are a synthesis of the literature review, the suppliers’ and the industrial users’ interviews. The objective is to build a synthesis and practical comparison tool between the different technologies and to underline the correct and proper usage of the method to obtain a reliable and trustable measure. Besides, the terms and the notions used in the ID-cards are described, explained and illustrated. They are also linked and underlined with best practices and vigilance points - that have to be kept in mind – gathered during the interviews of industrial users and suppliers.

3.3.1.1 Relevant criteria categories

As it is described above, the ID-cards contain 11 criteria: principle, implementation and installation conditions (straight lengths, pipe diameter range), benefits and drawbacks, main fields of application (with references to case studies), diffusion rate in industrial environment, operating conditions (type of fluid – humidity, etc.) and measurement range and performances, operational reliability, costs (investment price, maintenance and calibration), influencing factors and finally a non-exhaustive list of suppliers (Cf. APPENDIX 5.1). They are built thanks to bibliographic researches, supplier’s ’information (documentation and interviews)26 and industrial feedback27.

The choice of these criteria has been carried out with the phone interviews with the suppliers and also adapted after the interviews with the representatives of the industry (Cf. 2.5). This last point was a crucial part of the study: actually, the objective was to understand why the flow rate measurement was, in some specific cases, poorly controlled in the industry whereas the suppliers offered apparently reliable instrument. That is why the choice of a common set of criteria between the representatives of the industry the suppliers and the fluid mechanics theory was extremely important to link these stakeholders and offer the keys for a reliable measurement.

In this report of the work, due to confidentiality and ownership reasons, only some criteria will be explained.28

3.3.1.2 Reliability of a measurement device

The reliability of the measurement is not only a matter of reliable instrument but it also concerns the implementation of the device – the environment of the measurement (CETIAT, ADEME & DGCIS, 2014) (CETIAT, INERIS & LNE, 2004) (COSA Xentaur Corporation; Dr. J. David Hailey, 2015) (Enertime SAS, 2012) (JRC - Joint Reasearch Center, 2016) (JRC Joint Reasearch center, 2013) (Interview of the Scientific Director of RECORD) (Suppliers’ interviews). And both of these criteria are indispensable to make a reliable measurement. Even if most of the documentations of the suppliers spotlight the accuracy of their devices, it is essential to understand that a reliable measurement requires right location of the device (steady flow and representativeness of the measurement point), that factors can influence the measurement (in the case of biogas for instance, the variation of the gas composition influence the measurement since in many cases the calibration of the device require the value of the density requiring the gas composition Cf. 3.1.1.2.2). Moreover, as it has been enlightened in the part 3.1 a correct measurement of pressure and temperature is crucial to translate the values at normal conditions. Finally, a proper control of the probes is needed (humidity, condensation can obstructed the probes and

26 When information comes only from the supplier, it has been indicated on the ID-card in front of the specific piece of information. 27 A symbol has been placed in the ID-cards to identify the information collected during the industry’s interviews. 28 Nevertheless, a full and detailed description is available in the RECORD report (publically available here: http://www.record-net.org/reports ) in the section (E.1) on the report.


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lead to a measurement bias. The solution is this specific case is a filtration system upstream the measurement device or a periodic cleaning of the probes).

3.3.1.2.1 Reliability of a measurement device: inherent characteristics

In this study, it has been concluded that the reliability of the instrument itself is characterized by two notions: the reproducibility and the resolution.

The reproducibility is “the closeness of the agreement between the results of measurements of the same measurand29 carried out under changed conditions (locations, observer, etc.)” (Taylor, et al., 1994). It determines a confidence interval of 95% where the true value can be found.

The reproducibility is assessed with two identic AMS (Automatic Measurement System) in parallel. It is calculated with the average of the output signal every 30 min on experimentation site during 3 months.

At the end of the experimentation, the reproducibility has to be calculated with every valid pairs of values (from the two AMS). The following equations (CETIAT, INERIS & LNE, 2004) are used: the standard deviation of the pairs of measurement and the statistic confidence of 95% for the statistical distribution of these deviations:

Where:

- Rf is the reproducibility in site conditions - tn-1; 0.95 is the Student parameter of the t-distribution with a confidence range of

95% and with n-1 degrees of freedom (Encyclopedia of Mathematics, 2011) - sD is the standard deviation obtained with the pairs of measurements - x1,I is the output signal measured by the first measurement system - x2,I is the output signal measured by the second measurement system - n is the number of pairs of measurement

The notion of reproducibility combines the deviation of measurement between two measurement systems and their repeatability. That is why the reproducibility has been chosen in this study to illustrate the performance of a measurement system and the repeatability30 has been excluded. The resolution is the smallest variation measureable by the instrument (graduation scale on a ruler for instance).

The accuracy (or the precision) of an instrument has not been selected in this study because it characterizes a systematic error (contrary to the repeatability and so the reproducibility that characterize the random error). The values of the measurement are diverged from the true value: there is an offset. Then, it is always possible for an operator to calibrate the device in order to obtain accurate measure.

29 A measurand is a quantity intended to be measured. 30 The repeatability is the variation in measurements taken by a single person or instrument on the same item, under the same conditions, and in a short period of time. It represents the random error of the measurement.

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Figure 19: Illustration of the concepts of accuracy (or precision) and reproducibility, Source: (INRS, 2015)

These three concepts, reproducibility, resolution and accuracy, are inherent to the instrument. Nevertheless, the reliability of the measurement itself depends on others parameters which are inherent to the environment of the measurement. The concept of uncertainty represents the reliability of the measurement in its totality (device and environment). (Cf. 3.5.36)

Until the publication of the EN 16 911, the calculation of the uncertainty of the flow rate measurement was not compulsory or only mandatory in specific situation where local regulations are implemented (in Germany for instance or in France when prefectural decree imposes it). These calculations are carried out by certified organisations such Bureau Veritas. The comparison is realized with SRM – Standard reference methods – framed by the EN 16 911. (Cf. 3.5.1).

The reliability concerning the environment of the measurement is described in the ID-cards in different sections (because multiple factors can influence the reliability): implementation and installation conditions, location of the device operating conditions and influencing factors such as temperature, humidity, etc.

3.3.1.2.2 Environment of the measurement: the importance of straight length

According to the experts opinions collected during this study and the bibliographic researches, one of the crucial points for flow rate or velocity measurement is the respect of straight lengths before and after the sensor. These straight lengths are needed to obtain a symmetrical and steady flow. Actually, since many of the 9 techniques only measure one or few points of the velocity profile, the value at these points needs to be steady to always represent the mean value of the velocity (the calibration phase is there to find these representative points). This requires a symmetrical and steady flow.

The EN 16 911-2 standard recommends a distance of 25 Dh before the sensor and 5Dh after. Nevertheless, suppliers recommendations must be taken into account (the distances for specific technology can vary according to the devices inserted in the flow: type of valve, pipe bend, etc.).

Finally, the results of the flow profile cartography carried out by certified institution for the pre-study in the EN 16 911-2 (measurement QAL 2 for the choice of the location of the flow rate AMS – Automatic Measurement System - and the validity of representability of the measurement point) et the EN 15 269 (experiment of flow homogeneity related to all the Measuring System of stationary source measurement (Cf.3.5.3)) can reduce the preconized value of 25 Dh – 5 Dh (when these distances are impossible to meet on the industrial site).

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Figure 20: Recommendations for straight lengths upstream/downstream to obtain a steady, symmetrical flow

In this study, techniques that do not require straight length have also been identified and characterized.

3.3.1.2.3 Environment of the measurement: the importance of calibration

The calibration of a measurement devices in essential. Many technics are based on the differential pressure method: a devices creates a difference of pressure between the upstream and the downstream of the device, than thanks to the Bernoulli principle, this difference of pressure can be linked to the velocity of the flow (Cf. figure below). But, the Bernoulli principle uses the density of the fluid to link the velocity to the difference of pressure. This relation is enter in the transducer of the sensor only once, at the calibration stages during its installation. Thus, if the composition of the fluid varies, the calibration is no more valid and the output date of the flow meter is unreliable.

This issue has been taken carefully and has been deeply investigated during this study. It has been found31, even though the combustible composition (wastes) can varies, that of stack flue gases in waste treatment, since many treatments are always applied before the flow rate measurement to clean the flue gases, the gas composition does not vary much, at least not enough to impact the calibration of the device. Moreover, the following chart can illustrate the influence of the density on the velocity for a differential pressure method:

31 This conclusion has been confirmed with suppliers and representative of industry interviews.

Figure 21: Importance of the density in the calibration of differential pressure method in the flow rate calculation process

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Figure 22: Change in the velocity <v> measured by a Pitot tube in relation to the variation of the density of the fluid

In the industry, it is generally considered that re-calibration is not needed until a variation of the composition of 10%. Nevertheless, this is a real issue in the case of biogas where the variation of the composition can be much more important. This issue has been integrated in the final report and spotlighted for the biogas measurement.

The calibration consists also in the correct calibration of the sensor: off-set (calibrate thanks to the comparison with a Standard Reference Method Cf. 3.5.1.1) especially, realized by an accredited body.

3.3.1.2.4 Environment of the measurement: the importance of pressure and temperature measurement

As it has been underlined in the section 3.1.1.2.2, the temperature and the pressure is undeniably one of the most important parts of the flow rate measurement. On the first hand, it is required to translate the value from true conditions to normalized one (that are mainly required by the control authorities). On the other hand, it appears essential in the determination of the density needed for mass flow assessment that can be needed to determine the amount of emitted pollutant during a period of time. That is why special attention have been devoted to pressure and temperature measurement (Cf. 3.1.2 and 3.1.3). More information can be founded in the following study, devoted to stream measurement (Enertime SAS, 2012).

The temperature sensor has to be placed downstream and the pressure upstream. (RIQUIER, 2013).

3.3.1.2.5 Environment of the measurement: the importance of probes control

The major issue related to probe control is the possible interference of humidity and particles with the probed input signal. Many of the identified technics use pressure holes (that can be obstructed inducing a measurement error by particles or humidity), mirror or glass (that can be clogged by condensation or dust and inducing measurement errors). That is why special attention have been devoted to maintenance (frequency of cleanness especially), type of fluid (charged – in terms of particles sizes and concentration, humid) that every method can handle to minimize the influence of these parameters on the measurement (and so the possible measurement bias).

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-10,00%

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-30% -25% -20% -15% -10% -5% 0% 5% 10% 15% 20% 25% 30%

Var

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Variation of the density

Change in the velocity <v> measured by a Pitot tube in relation to the variation of the density of the fluid

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3.4 Technology comparison This section provides a comparison tool for the industries. Different criteria have been used related to the type of fluid, the environment of the measure, the cost, etc. 32This section of the report is the most essential one. It helps industry to choose between the different 9 techniques to offer the most adapted device according to the environment of the measure (pipe inner diameter, etc.), the type of fluid, the quality of the measurement needed, etc. among others. But this tool has to be used only as a first step in the process of reliable measurement. Actually, once the best method has been found, the industry needs to refer to the ID-cards of this method where he can found the best practices for this specific technic (straight length recommendations, installation, calibration, temperature and velocity range, etc.) (Cf. APPENDIX 3) and the general information in the theoretical section. The choice of the relevant selection criteria has been validated with the steering committee.

The quality of the measurement (inherent to the device) is an important factor for reliability but other parameters depending on the operative conditions (humidity, charged, temperature, low velocity), the installation site (straight length, mono-point possible or averaging33 measurement required, pressure losses possible or not), the environment of the measurement (ATEX34 certification). The cost of the device itself

32 Due to ownership reasons, the technology comparison table cannot be directly published in the study. But it is directly available in the RECORD report (publically available here: http://www.record-net.org/reports ) in the section (F) on the report. 33 An averaging measurement gives a better representativeness of the mean velocity on the section but in the case of a symmetrical, steady flow a mono-point measurement at 12% of Dh is fully reliable. (Cf. 3.3.1.2.2). 34 ATEX: The ATEX directive consists of two EU directives describing what equipment and work environment is allowed in an environment with an explosive atmosphere (DIRECTIVE 1999/92/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL, 2000).

Pitot T

ube

Ultras

ound

Thermal

Mas

s

Differe

ntial

pressu

re

Propell

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anem

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Meth

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Meth

od X

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Measurement continuous or

punctualC. or P. C. or P. C. or P. C. or P. C. or P. C. or P. C. or P. C. or P. C. or P. C. or P.

Humidity ≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈

Charged (with particles)

≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈

Straight lenght x x x x x x x x x x

Most adapted diameter

Small to mediaum to large










Low velocity measurement

possiblex x x x x x x x x x

Pressure losses ≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈ ≈

Quality of the measurement

+++ +++ +++ +++ +++ +++ +++ +++ +++ +++

Measurement mono-point or

averagingM-P or AVR M-P or AVR M-P or AVR M-P or AVR M-P or AVR M-P or AVR M-P or AVR M-P or AVR M-P or AVR M-P or AVR

Costs XX to YY k€ XX to YY k€ XX to YY k€ XX to YY k€ XX to YY k€ XX to YY k€ XX to YY k€ XX to YY k€ XX to YY k€ XX to YY k€

Temperature -40 to 450°C -40 to 450°C -40 to 450°C -40 to 450°C -40 to 450°C -40 to 450°C -40 to 450°C -40 to 450°C -40 to 450°C -40 to 450°C

ATEX certification

v v v v v v v v v v

Figure 23: Technology comparison tool, Dummy data


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cannot be taken as criteria but it can be used to choose between two devices that have met all the other requirements for instance.

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3.5 European standards analysis and synthesis This section enlightens notions and important issues that can be found in the European standards related to air emission monitoring: the EN 15 259, 14 181, 15 267 and the last released the EN 16 911that will be implemented next year, in 2017.

Modalities of emissions monitoring – CEMS (Continuous Emissions Monitoring Systems – are framed by regulation. In order to assess the quantity of pollutant released, it is crucial to know the chemical composition of the flue gases as well as the flow rate. The flow rate measurement has been standardized by the EN 16 911 recently published and that will entry to force in 2017. The EN 15 259, 14 181 and 15 267 standards describe more broadly the AMS – Automatic Monitoring System – composed of gas analyzer and flowmeter among others.

3.5.1 EN 16 911: Stationary source emissions -- Manual and automatic determination of velocity and volume flow rate in ducts

3.5.1.1 EN 16 911-1

This section of the standard describes the SRM (Standard reference material) used by accredited bodies for control and calibration of the AMS (Automatic Measurement Systems). This part only concerns the devices used by the accredited bodies and do not interfere in the measurement process for the industrial.

The measurement objectives of the SRM are:

- The measurement of the velocity at a specific point of the pipe - The measurement of the velocity profile in a cross-section of the pipe - The assessment of the gyrations - The calibration of a flow rate AMS; this calibration can be realized by volumetric flow rate

comparison or velocity comparison - The periodic measurement of the volumetric flow rate in a cross-section of the pipe.

The Standard Reference Materials to reach the previous objectives are:

- Pitot tube35 - Propeller anemometer - Tracing method - Calculation method of the flow rate from energy consumption

This section also defines the performances criteria (uncertainty, reproducibility, etc.) that the SRM has to reach. Nevertheless, since it only concerns control organisms it does not appear in this study. (POULLEAU, 2014). The APPENDIX 2 presents a QAL 1 certificate for a Pitot tube.

3.5.1.2 EN 16 911-2

This section of the EN 16911 is the most important one, since it specifies the performances criteria that an AMS has to reach. Thus, it defines the QAL 1 frame (Cf. 3.5.3), QAL 2, QAL 3 and AST as required by the EN 14 181 but with a specific attention for flow rate measurement system.36

The relevant performances characteristics of the AMS must be documented by the manufacturer (and/or its European represent) by proficiency tests. A QAL 1 certificate (Cf. APPENDIX 2) is provided when the AMS reaches objectives in terms of response time, standard deviation, linearity deviation, temperature, vibrations and supply voltage sensitivity and finally the measurement uncertainty, that you can find directly in the RECORD report or in the EN 16911-2 sections.

35 This section of the EN 16 911 substitutes the EN 10 780 on good practice related to velocity measurement with a Pitot tube. 36 The EN 14181 defines the quality assurance standard procedure for all the air emission measurement devices (gas analyzer, dust monitoring and velocity/flow rate measurement devices).

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Besides, its provides a performances range that the AMS must reach on site (QAL 2) with the calibration criteria, the response time, the period of time between each checking and maintenance process (periodicity of the QAL 2 checks), its reproducibility and finally the uncertainty of the measurement. (Cf. RECORD report on website or EN 16911-2 section).

The AMS needs to be calibrated by comparison with a SRM by a control organism.

3.5.1.3 EN 16 911-3

This section describes adapts the Quality assurance standard of the EN 14181 procedure for flow rate/velocity AMS (Cf. Section 3.5.3).

3.5.2 EN 15 259: Air quality - Measurement of stationary source emissions. Requirements for measurement sections and sites and for the measurement objective, plan and report

This standard offers recommendations on the choice of the measurement plan and especially the straight lengths requires mentioned above. The standard also describes the preparation of measurement campaigns, its realization and the reporting of the results (periodicity, labelled organisms, etc.)

3.5.3 EN 14 181: Stationary emissions – Quality assurance of Automatic Measuring Systems

The EN 14 181 standard defines the quality assurance process for air emission AMS (gas analyzer, dust monitoring and velocity/flow rate measurement devices). Four steps are defined the QAL 1 realized before the use and the sale of the AMS on the request on the manufacturer and the QAL 2, 3 and AST during its use.

Figure 24: Quality assurance standard process for air emission AMS, source: (Vivarat-Perrin, 2006) and EN 14 181

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4 Conclusions This part concludes the work presented, underlines the answers provided to the researches questions, the impact on the study and also enlightens knowledge gathered during the master thesis realization at Alcimed.

The flow rate assessment of stack flue gases is the very first step in the bottom-up GHG emissions evaluation. Besides, it is an essential data in the carbon trade in the EU but its impact is also non-negligible on the local environment of a stationary sources. That is why many local regulations have been implemented over the years with many different constraints. Besides, many different methods can be found on the market, with best practices not always clearly identified that could possibly lead to important uncertainties (uncontrolled influences of environment parameters on the measurement, non-representativeness of the measurement points, unsteady and non-symmetric velocity profile, mistakes due to calibration, etc.). Therefore, a European standard 16 911 has recently emerged to regulate, frame and homogenize this measurement. However, the diversity of the methods, the multitudes of reliability’s notions used by the suppliers (repeatability, reproducibility, accuracy, precision and uncertainty) and the lack of comparison tools could possibly confuse representatives of the industry themselves. Even though, the recent European standard EN 16911 is still debated and only a dozen of devices are certified QAL 1 (Cf. APPENDIX 3) while the major part of the industries is not using QAL 1 certified products for the moment.

Thus this study theorizes, clarifies, compares and summarizes the measurement of stack flue gases and biogas for the waste treatment industry. Concerning the first question “How can flow rate measurement of flue gases be reliable” and its sub-questions, the theoretical part of this study37 offers the theoretical background needed to answer the RQ 1.1 for gas flow rate assessment and underlines factors that can influence the measurement (mainly temperature, pressure and representativeness of the velocity measurement point) and can lead to non-reliable value. Then, the comparison tool38 allows a choice of the most adapted method according to 12 criteria answering the RQ 1.2. Besides, the nine ID-cards39, built thanks to bibliographic researches, suppliers’ advices and industrial ’feedbacks40, describe and gather best-practices and operational requirements linked to the technology answering the RQ 1.3. Finally, the analysis and the summary of the European standards41 as well as the key messages included in the ID-cards and in the theoretical part deliver the requirement to fully apply these regulations. In conclusion, the two research questions and their sub-questions have been answered in this paper and in the RECORD study.

37 The theoretical part can also be found in the RECORD report (publically available here: http://www.record-net.org/reports ) in the sections (C.1 and C.2). 38 The comparison tool can be found in the RECORD report (publically available here: http://www.record-net.org/reports ) in the section (F). It cannot fully appear in this study due to ownership reason. 39 The nine ID-cards fully completed can be found in the RECORD report (publically available here: http://www.record-net.org/reports ) in the section (E.2). It cannot fully appear in this study due to ownership reason. 40 A symbol has been placed in the ID-cards to identify the information collected during the industry’s interviews. 41 The theoretical part can also be found in the RECORD report (publically available here: http://www.record-net.org/reports ) in the sections (APPENDIX 1).








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Finally, the cooperation side of this project involving industrial leaders of waste treatment industry in the steering committee and the report publically published offer a remarkable spotlight on the question of the reliability of the CEMS42 and a multitude of diffusion channels among the industries and so will contribute to a more reliable air emission monitoring. This diffusion channels are even stronger among the members of RECORD which include: Public organism (French ministry of Environment, ADEME43), Leading waste and water treatment industry (SUEZ, VEOLIA, Groupe TIRU/EDF), energy utilities (ENGIE, EDF), transportation companies (SNCF44, RENAULT), Chemical industry (SOLVAY), Oil & Gas (TOTAL) among others.

To conclude on the realization of this study; from the researches of information, the raise of issues, the collection of the information during the phone interviews to the writing of the report; it has enlightened that, as future engineers, we need to quickly identify an issue, formulate (and often reformulate in course of the project) questions, and sub-questions as the work is more and more precise. But it has also highlighted that it is necessary to quickly develop the specific vocabulary of a field, its problematic in order to be able to communicate, to interact with experts (from the commercial of a sensor company to the R&D engineer in charge of metrology in a leading energy company including the metrology operator on a waste treatment site). Finally, most of all, this project has taught me that the most difficult part is to be able to communicate synthetically and clearly the information, without losing the shades or the tricky parts of a notion, to create a simple in form but complete in substance guiding tool for industrial metrology’s experts.

42 CEMS : Continuous Emissions Monitoring Systems 43 ADEME 44 SNCF – National French railway company

Figure 25: Illustration of the objectives and the answers given to the research questions

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5 APPENDICES

5.1 APPENDIX 1: Techniques ID card template Two templates of “ID-cards” are presented below. Grey blocks cover their content due to ownership reasons. But the nine ID-cards can be found directly in the RECORD report (publically available here: http://www.record-net.org/reports ) in the section (E.2). On these two examples, the Pitot tube and the ultrasound-transit time velocimeter, you can read the operation principle and see the structure of the ID-cards with the 11 criteria.


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5.2 APPENDIX 2: Uncertainty calculation for the QAL1 certification of a Pitot tube manufactured by PCME Ltd. (TUV Rheinland, 2016)

The following document presents the calculations of the uncertainty related to the QAL 1 certification (EN 16911-2) of flow rate/velocity meters. In the following example, the device is a Pitot tube manufactured by PCME.

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5.3 APPENDIX 3: QAL 1 certificated flow rate/velocity products (MCerts; SIRA certification; CSA group, 2016) (TUV Rheinland, 2016)

The following table lists all the devices45 for velocity/flow rate measurement certified QAL 1 (EN 16911-1). As you can see, their number is limited since the standard is recent.46

45 At the following date : 12/21/2016 46 A list of about 50 suppliers (not only the QAL1 certified) can be found in attached file of the RECORD report (publically available here: http://www.record-net.org/reports ).

Company Method of measurement

Product Characteristics (*QAL 1 certified velocity range)

CODEL international

infrared correlation VCEM 5100 diameter: 0,5-15 m Temperature: from 40 to 850 °C velocity*: 3 - 50m/s reproducibility (certification QAL1): 1,8 % materials available: stainless steel, other materials optional installation: 2 probes to place underneath one another separated by 0,5 - 1m Pressure, temperature sensor: N/A ATEX certification: NON output data : velocity, flow rate

FCI - Fluid Component International

thermal mass MT 91 diameter: mono-point or averaging (until 16 measurement points) - on-demand length Temperature: until 454 °C velocity*: 0 - 25m/s flow rate normalized: 0,08 à 45 Nm/sec reproducibility (certification QAL1): 1% materials available: stainless steel, Hastelloy, Nickel et Chromium installation: one unique insert point Pressure, temperature sensor: N/A ATEX certification: optional output data : mass flow rate, temperature

Kurz International

thermal mass K BAR 2000 B diameter: averaging Temperature: until 454 °C velocity*: 0 - 30m/s flow rate normalized: 0,08 to 45 Nm/sec reproducibility (certification QAL1): 0,25% materials available: stainless steel, Hastelloy, Nickel and Chromium installation: one unique insert point Pressure, temperature sensor: N/A ATEX certification: optional output data : mass flow rate, temperature

ABB Pitot tube Stack flow meter system

diameter: 1 - 8 m Temperature: until 1200 °C velocity*: 3-35 m/s (certified) reproducibility (certification QAL 1): 1,8 % materials available: Hastelloy, stainless steel installation: 2 insert points (optional) or partial insertion (optional) Pressure, temperature sensor: optional ATEX certification: optional output data : velocity, flow rate volumetric and mass

Durag Pitot tube D FL 100 Flow monitor

diameter: 0,5 -10 m Temperature: until 600 °C velocity*: 3-50 m/s (certified) reproducibility (certification QAL 1): 1% materials available: stainless steel, other materials on-demand installation: N/A Pressure, temperature sensor: optional ATEX certification: Yes - EAC Gost Ex Zone 2 output data : N/A

SKI Pitot tube Accuflow diameter: > 0,1 m Temperature: until 800 °C velocity*: 2-20 m/s (certified) reproducibility (certification QAL 1): 2,7% materials available: stainless steel, Hastelloy, other materials on-demand installation: 2 insert points (optional) or partial insertion (optional) Pressure, temperature sensor: optional ATEX certification: N/A output data : N/A


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Dr Födish Pitot tube FDM 09 et FDM 02

diameter: > 0,08 m Temperature: until 280 °C velocity*: 2-30 m/s (certified) reproducibility (certification QAL 1): 2,0% materials available: stainless steel installation: partial insertion Pressure, temperature sensor: integrated ATEX certification: N/A output data : velocity, flow rate (true and normal conditions)

Horriba Pitot tube EM-F5000 diameter: >4m Temperature: until 700 °C velocity*: 3-30 m/s (certified) reproducibility: 2% materials available: stainless steel installation: two insertion points Pressure, temperature sensor: integrated ATEX certification: N/A output data : integrated system with gas analyzer EM-D5100 and velocity measurementEM-F5000

Environnement SA

Pitot tube StackFlow 200 diameter: 0,45 - 5 m Temperature: until 500 °C velocity*: 2 - 30 m/s reproducibility (certification QAL1): materials available: stainless steel installation: 2 insertion points (optional) or partial insertion (optional) Pressure, temperature sensor: integrated ATEX certification: optional output data : velocity flow rate (true and normal conditions)

Durag Ultrasounds D FL 220 Flow monitor

diameter: 0,5 -13 m Temperature: until 300 °C velocity*: 0 - 30m/s reproducibility (certification QAL1): 1,1% materials available: stainless steel, others materials optional installation: 2 probes facing each other’s with an angle from 30 to 45 ° Pressure, temperature sensor: Oui ATEX certification: optional output data : velocity, flow rate and temperature (true and normal conditions)

PCME Ultrasounds Stack Flow 400 diameter: > 0,5 m Temperature: until 200 °C velocity*: 0 - 30m/s reproducibility (certification QAL1): 0,9 % materials available: Hastelloy installation: one unique insert point to insert a probe at 45° on which two ultrasonic probes are assembled separated by 400 mm Pressure, temperature sensor: N/A ATEX certification: N/A output data : velocity, flow rate

Sick Ultrasounds Flowsic 100 diameter: 0,15 - 11,3 m Temperature: until 450 °C velocity*: 0 - 30m/s reproducibility (certification QAL1): 1 % materials available: stainless steel installation: 2 probes facing each other’s with an angle from 30 to 60° Pressure, temperature sensor: N/A ATEX certification: N/A output data : velocity, temperature, flow rate(true and normal conditions)

Figure 26: List of the QAL1 certified devices for flowrate/velocity measurement, (MCerts; SIRA certification; CSA group, 2016) (TUV Rheinland, 2016)

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Acknowledgements Firstly I would like to thanks my manager at ALCIMED Mr. LUCAS Ronan and my KTH supervisor Mr. LEVIHN Fabian for their advices, their teachings and their helps during my project. I would also like to acknowledge my colleagues and more particularly Mr. DEMIREL Enis, Mr. TORRIN Arthur and Mrs. EL MEJJAB Ibtissam for their help during my work and their precious advices. Besides, I am truly thankful to the Energy and Environment team and the ALCIMED Company for offering me the opportunity to conduct my thesis and to live wonderful experiences. Finally, I would also like to thanks the experts interviewed during the study, without their participation the study would not have been successfully conducted.

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List of figures Figure 1: Global mean surface temperature increase as a function of cumulative total global carbon dioxide (CO2) emissions from various lines of evidence, source: (IPCC, 2014) ................................................ 8 Figure 2: Total anthropogenic greenhouse gas (GHG) emissions by economic sector (gigatons of CO2- equivalent per year, GtCO2-eq/yr) from economic sectors in 2010, source: (IPCC, 2014) ............................. 9 Figure 3: The role of flow rate measurements in the assessment of pollutant emission .................................10 Figure 4: Methodology of the study - Objectives & means implemented .........................................................14 Figure 5: Main sources used during the literature review .....................................................................................16 Figure 6: Evolution of the density of gas composed of air in function of the temperature ...........................21 Figure 7: Evolution of the mass flow rate in function of the temperature ........................................................22 Figure 8: Evolution of the mass flow rate in function of the density of the fluid ............................................23 Figure 9: Velocity profile in laminar flow regime ...................................................................................................24 Figure 10: Velocity profile in turbulent flow regime .............................................................................................24 Figure 11: Length entrance for a laminar flow, source: Aerospatiale Department, Fluid mechanics course, University of Sidney ....................................................................................................................................................25 Figure 12: Velocity profile of a steady and turbulent flow ...................................................................................25 Figure 13: Illustration of the evolution of the velocity profile in presence of an elbow upstream, (COSA Xentaur Corporation; Dr. J. David Hailey, 2015) ..................................................................................................26 Figure 14: Straight length recommendation, EN 16911-2 ....................................................................................25 Figure 15: Flow rate assessment process .................................................................................................................27 Figure 16: Main pressure measurement methods ...................................................................................................29 Figure 17: Main temperature measurement methods ............................................................................................30 Figure 18: Main methods of common gaseous components measurement (CHATAIN, et al., 2014) .........31 Figure 19: Illustration of the concepts of accuracy (or precision) and reproducibility, Source: (INRS, 2015) ........................................................................................................................................................................................36 Figure 20: Recommendations for straight lengths upstream/downstream to obtain a steady, symmetrical flow ................................................................................................................................................................................37 Figure 21: Importance of the density in the calibration of differential pressure method in the flow rate calculation process .......................................................................................................................................................37 Figure 22: Change in the velocity <v> measured by a Pitot tube in relation to the variation of the density of the fluid ....................................................................................................................................................................38 Figure 23: Technology comparison tool, Dummy data ........................................................................................40 Figure 24: Quality assurance standard process for air emission AMS, source: (Vivarat-Perrin, 2006) and EN 14 181 ....................................................................................................................................................................43 Figure 25: List of the QAL1 certified devices for flowrate/velocity measurement, (MCerts; SIRA certification; CSA group, 2016) (TUV Rheinland, 2016) ......................................................................................55 Figure 26: Illustration of the objectives and the answers given to the research questions ..............................45

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