Guidelines for determination of flare quantities from upstream oil and gas facilities

Transcription

1 Hydrocarbon management HM 58 Guidelines for determination of flare quantities from upstream oil and gas facilities 2nd edition

2 HM 58 GUIDELINES FOR DETERMINATION OF FLARE QUANTITIES FROM UPSTREAM OIL AND GAS FACILITIES 2 nd edition July 2017 Published by Energy Institute, London The Energy Institute is a professional membership body incorporated by Royal Charter 2003 Registered charity number

3 The Energy Institute (EI) is the chartered professional membership body for the energy industry, supporting over individuals working in or studying energy and 250 energy companies worldwide. The EI provides learning and networking opportunities to support professional development, as well as professional recognition and technical and scientific knowledge resources on energy in all its forms and applications. The EI s purpose is to develop and disseminate knowledge, skills and good practice towards a safe, secure and sustainable energy system. In fulfilling this mission, the EI addresses the depth and breadth of the energy sector, from fuels and fuels distribution to health and safety, sustainability and the environment. It also informs policy by providing a platform for debate and scientifically-sound information on energy issues. The EI is licensed by: the Engineering Council to award Chartered, Incorporated and Engineering Technician status; the Science Council to award Chartered Scientist status, and the Society for the Environment to award Chartered Environmentalist status. It also offers its own Chartered Energy Engineer, Chartered Petroleum Engineer and Chartered Energy Manager titles. A registered charity, the EI serves society with independence, professionalism and a wealth of expertise in all energy matters. This publication has been produced as a result of work carried out within the Technical Team of the EI, funded by the EI s Technical Partners. The EI s Technical Work Programme provides industry with cost-effective, value-adding knowledge on key current and future issues affecting those operating in the energy sector, both in the UK and internationally. For further information, please visit The EI gratefully acknowledges the financial contributions towards the scientific and technical programme from the following companies BP Exploration Operating Co Ltd RWE npower BP Oil UK Ltd Saudi Aramco Centrica Scottish Power Chevron SGS CLH Shell UK Oil Products Limited ConocoPhillips Ltd Shell U.K. Exploration and Production Ltd DCC Energy SSE DONG Energy Statkraft EDF Energy Statoil ENGIE Talisman Sinopec Energy (UK) Ltd ENI Tesoro E. ON UK Total E&P UK Limited ExxonMobil International Ltd Total UK Limited Kuwait Petroleum International Ltd Tullow Oil Maersk Oil North Sea UK Limited Valero Nexen Vattenfall Phillips 66 Vitol Qatar Petroleum World Fuel Services However, it should be noted that the above organisations have not all been directly involved in the development of this publication, nor do they necessarily endorse its content. Copyright 2017 by the Energy Institute, London. The Energy Institute is a professional membership body incorporated by Royal Charter Registered charity number , England All rights reserved No part of this book may be reproduced by any means, or transmitted or translated into a machine language without the written permission of the publisher, ISBN Published by the Energy Institute The information contained in this publication is provided for general information purposes only. Whilst the Energy Institute and the contributors have applied reasonable care in developing this publication, no representations or warranties, express or implied, are made by the Energy Institute or any of the contributors concerning the applicability, suitability, accuracy or completeness of the information contained herein and the Energy Institute and the contributors accept no responsibility whatsoever for the use of this information. Neither the Energy Institute nor any of the contributors shall be liable in any way for any liability, loss, cost or damage incurred as a result of the receipt or use of the information contained herein. Hard copy and electronic access to EI and IP publications is available via our website, Documents can be purchased online as downloadable pdfs or on an annual subscription for single users and companies. For more information, contact the EI Publications Team. e: pubs@energyinst.org

4 CONTENTS Page Foreword Acknowledgements Introduction Scope Background EU Emissions Trading Scheme (EU ETS) Key legislation covering flaring and venting Objectives for flaring and vent consent Approach to flare consent application Developing legislation worldwide Alternative country legislation Categorisation, selection and methods Installation categories Source stream categorisation The tier system Tier selection Calculation factor tier selection (special rules) Source stream measurement approaches Calculation-based approaches Standard calculation-based approach Mass balance calculation approach Measurement-based approach Fall-back approach Operational considerations Pressure high and low flare systems Temperature high and low flare systems Temperature reference conditions Gas composition Acid gas flares Determination of flare quantity (flow rate) Indirect determination 'By-difference' method to determine total flare Inventory calculation Direct determination of flare quantity Dedicated flare meter approach Distributed metering approach Combination of direct and indirect determination of flare quantity Flare composition EU ETS emissions factor

5 Contents continued Page 8 Flare metering technologies Flow meter selection criteria Flow meter installation considerations Ultrasonic transit time meters Thermal mass flow meters (TMFs) Optical flow meters Determination of flare composition Indirect determination of flare composition Direct determination of flare composition Manual gas sampling and offline analysis by gas chromatograph Automatic gas sampling and offline analysis by gas chromatograph Online gas chromatographs Optical spectroscopy Determining molecular weight from speed of sound measurement Flow meter installation considerations Installation effects Use of CFD techniques to determine flow meter installation error Effect of Reynolds number Laminar/turbulent flow Roughness Uncertainty Sources of uncertainty Basic meter uncertainty Pipe diameter, D Flow-related sources of uncertainty Environmental sources of uncertainty Secondary instrumentation Uncertainty in the calculation of Z Data acquisition Source of uncertainty in flare quantity using ultrasonic flare gas meters Metrology contributions (D, L and x) for ultrasonic flare gas meters Flow-related sources of uncertainty for ultrasonic flare gas meters Uncertainty in ultrasonic flare gas meters owing to environmental effects Uncertainty in the calculation of Z and M for ultrasonic meters Sources of uncertainty in flare gas quantity using thermal mass flow meters Sources of uncertainty in flare gas quantity using optical flare gas meters Uncertainty in flare quantity calculated using the by-difference technique Sources of uncertainty in the determination of f e Uncertainty in f e obtained by gas sampling Calibration and verification Laboratory calibration of flare gas meters Meters installed in situ In situ calibration of flare gas meters Insertion probe techniques Gas tracer techniques

6 Contents continued Page 12.3 In situ verification of flare meters Ultrasonic transit time meters Thermal mass probes Optical meters Calibration and meter verification competency Transferred/inherent CO 2 and CCS Transferred CO 2 and CCS Inherent CO Zero/near zero flaring References Other useful web links and references Annexes Annex A Sample investigation into installation effect on an ultrasonic flare gas meter using CFD analysis...78 A.1 Methodology A.2 Uncertainty in the CFD method...79 Annex B Symbols, abbreviations and terminology B.1 Glossary of symbols Greek symbols Prefixes and subscripts B.2 Abbreviations B.3 Terminologies and definitions

7 Figures Figure 1 LIST OF FIGURES AND TABLES Page Method of obtaining mass flow rate from the speed of sound measurement at low pressure (ideal gas assumed) Figure A.1 Geometry and computational meshes used for the CFD simulation...79 Figure A.2 Illustration of data extraction method used in the CFD analysis...79 Tables Table 1 A brief description of each trading period...11 Table 2 EU ETS regulatory organisations Table 3 Flaring and venting legislation in U.S. and Canada Table 4 Installation categories...16 Table 5 Source stream categories Table 6 Example of tier system selection possibilities for a calculation-based approach...17 Table 7 Calculation approach summary...18 Table 8 Measurement approach summary...19 Table 9 Tiers for CEMS (maximum permissible uncertainty for each tier) Table 10 Minimum requirements for measurement-based methodologies...24 Table 11 Overall uncertainty thresholds for installations adopting the fall-back approach...26 Table 12 Sensitivity of Q N to changes in the input parameters...34 Table 13 Sensitivity of Q N to changes in the input parameters for an optical meter Table 14 Example of uncertainty in the by-difference technique during normal flaring...59 Table 15 Example of uncertainty in the by-difference technique during blowdown of an export line...61 Table 16 Example of sensitivity coefficients of f e to x i for a methane-rich gas mixture...61 Table 17 Student s t table (for a two-tailed distribution)

8 FOREWORD The EI Hydrocarbon Management Committee is responsible for the production and maintenance of guidelines covering various aspects of static and dynamic measurement of petroleum and hydrocarbon gases. This publication has been instigated and managed by the Energy Institute s (EI) Upstream Hydrocarbon Management Committee, HMC-1, which deals with measurement applicable to the upstream sector of the industry and includes measurement for fiscal reporting, product allocation and streams associated with emissions trading. Flaring and venting are methods of burning or releasing associated gas that is treated as a waste product from an offshore installation or gas terminal. This is necessary for maintaining process safety or for disposal of gas that it is technically or economically impractical to collect and transport. Greenhouse gas emissions from oil and gas production are currently covered by 'The Greenhouse Gas Emissions Trading Scheme Regulations of 2012' Directive 2003/87/EC. This monitoring and reporting regulation (MRR Phase III) was implemented in January The 1 st edition of HM 58 was published in HMC-1 have now developed a 2 nd edition of HM 58 to provide up-to-date guidance on the application of measurement techniques and principles needed to comply with the current European Union Emissions Trading Scheme (EU ETS) requirements for the trading of flared quantities discharged from facilities involved in the upstream oil and gas industry. This publication will be a useful aid to measurement specialists, environmental personnel and operations management principally within the UK upstream oil and gas industry. It will also be a valuable aid to similar personnel from other countries where controls on discharges from flares are being enforced. This publication has been compiled for guidance only and while every reasonable care has been taken to ensure the accuracy and relevance of its contents, the Energy Institute, its sponsoring companies, the document writer and the Working Group members listed in the Acknowledgements who have contributed to its preparation, cannot accept any responsibility for any action taken, or not taken, on the basis of this information. The Energy Institute shall not be liable to any person for any loss or damage which may arise from the use of any of the information contained in any of its publications. These guidelines may be reviewed from time to time and it would be of considerable assistance for any future revision if users would send comments or suggestions for improvements to the Technical Department, Hydrocarbon Management, Energy Institute, 61 New Cavendish Street, London, W1G 7AR (e:technical@energyinst.org) 7

9 ACKNOWLEDGEMENTS The Energy Institute (EI) wishes to record its appreciation of the work carried out by the following individuals: Nigel Bellew of Intertek: Calibration and Metering Services (CMS) for the preparation of these guidelines. Members of the HMC-1 Flare Measurement Working Group who have assisted with steering the project and for providing valuable expertise: John Alborough Nulab Martin Basil Solv Ltd Ian Bates Total Paul Batty BEIS Simon Barons ConocoPhillips Jim Barton BP Baron Bennington SGS Murdoch Campbell TAQA Paul Daniel Emerson Alan Elphinstone Accord-ESL Heather Fitzgerald H and D Fitzgerald Douglas Griffin OGA Mark Hay Kelton Phil Hunt Oneflo Jason Laidlaw Emerson Walter Macdonald Accord-ESL Alick MacGillvray TUV NEL Sandy Marshall Nexen Christopher Mills TUV NEL David Newman BP Richard Paton Consultant/Petrofac Denis Pinto Premier Oil Michael Reader-Harris TUV NEL Bob Sim Shell Stephen Smyth Petrofac Eddie Spearman CNR Alan Spence Accord-ESL The Energy Institute also wishes to acknowledge contributions made by the following personnel: Martin Bruce Gordon Mackie Intertek: Calibration and Metering Services (CMS) GE During the development of this publication, other members of HMC-1 and other industry personnel were provided with copies for reference and were advised of progress. 8

10 1 INTRODUCTION Our planet s climate is anything but simple: all kinds of factors influence it. However, despite all the complexities, a firm and ever-growing body of evidence points to a clear picture: the world is warming, and this warming is due to human activity increasing levels of greenhouse gases in the atmosphere, and if emissions are allowed to continue, then global warming will continue too, with increasingly serious consequences. The EU ETS (European Union Greenhouse Gas Emission Trading Scheme) Directive 2003/87/EC was implemented from (Phase II), and for the first time, the scheme included emissions from offshore installations, which focused on the verification and integrity of measured data. Phase III has now commenced from which is focused on more consolidated rules based on the knowledge and data gathered during Phase II. The good news is that from , UK carbon emissions fell dramatically by 8,4 % whilst the economy grew faster than it has in any year since This was mainly due to a reduction in coal use and the generation of energy from renewable sources, but it illustrates how carbon reduction can play a crucial role in curbing the inevitability of global warming. Source Guardian Activities such as the burning of produced gas as fuel for power generation, and the safe evacuation of excess gas through emergency flaring, comprise the major source of CO 2 emissions from upstream oil and gas facilities. The major difficulty in managing flaring is accurately identifying how much gas is coming from the various sources that contribute to the overall flare volume. The measurement of emissions from flares is different to other gas-flow measurement and emission measurement applications due to the unpredictable nature of flaring, and the often hostile environment offshore makes exact measurement an extremely difficult and complex task. Both the quantity of gas delivered to flare and its composition are required to determine the mass of CO 2 released to atmosphere for EU ETS reporting purposes. Molecular weight is required in order to calculate the total mass of gas flared for the Department for Business, Energy and Industrial Strategy (BEIS) reporting purposes; this can also be determined from the gas composition or directly using online measurement instrumentation. The units of the figures reported to BEIS (i.e. tonnes of gas flared) should not be confused with those reported to the EU ETS (tonnes of CO 2 produced by flaring). 9

11 2 SCOPE The purpose of this publication is to provide guidance to oil and gas duty holders who monitor and report CO 2 emissions and to assist operators with interpretation of the requirements of the EU Emissions Trading Scheme (EU ETS) with regard to achieving the highest standard of monitoring for carbon dioxide emissions, as defined in the Commission Regulation (EU) No. 601/2012 of 21 June 2012, and the EU Monitoring and Reporting Regulation Guidelines (MRR Guidance document No. 1 (MRR), ('M&R Guidelines')). 10