Fugitive Emissions

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0 INTRODUCTION

The four main sources of Fugitive Emissions on most plants are valves, machine seals, re-makable joints and pressure relief devices. Other possible sources include open-ended lines, sampling connections, drains and vents.

Sometimes special precautions are taken to minimize Fugitive Emissions, for example the use of bellows seal valves. However, generally no special precautions are taken and the subsequent Fugitive Emissions to atmosphere represent a significant amount of plant losses.

Regulatory requirements covering Fugitive Emissions exist in many countries and therefore a leak reduction program should be implemented. Fugitive Emissions also represent financial losses to the business as well as potential damage to the environment.

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Fugitive Emissions

  1. 1. GBH Enterprises, Ltd. Manufacturing & Engineering Guide: GBHE-OE-007 Fugitive Emissions Process Information Disclaimer Information contained in this publication or as otherwise supplied to Users is believed to be accurate and correct at time of going to press, and is given in good faith, but it is for the User to satisfy itself of the suitability of the Product for its own particular purpose. GBHE gives no warranty as to the fitness of the Product for any particular purpose and any implied warranty or condition (statutory or otherwise) is excluded except to the extent that exclusion is prevented by law. GBHE accepts no liability for loss, damage or personnel injury caused or resulting from reliance on this information. Freedom under Patent, Copyright and Designs cannot be assumed. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com
  2. 2. Operational Excellence: Fugitive Emissions CONTENTS 0 INTRODUCTION 1 SCOPE 2 DEFINITIONS 2.1 3 Fugitive Emission REDUCTION OF FUGITIVE EMISSIONS 3.1 3.2 3.3 3.4 4 Valves Machine Seals 3.2.1 Pumps 3.2.2 Compressors Remakable Joints Pressure Relief Devices MONITORING OF FUGITIVE EMISSIONS 4.1 5 Management System FURTHER INFORMATION 5.1 5.2 Related External Publications Related Internet Sites Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com
  3. 3. 0 INTRODUCTION The four main sources of Fugitive Emissions on most plants are valves, machine seals, re-makable joints and pressure relief devices. Other possible sources include open-ended lines, sampling connections, drains and vents. Sometimes special precautions are taken to minimize Fugitive Emissions, for example the use of bellows seal valves. However, generally no special precautions are taken and the subsequent Fugitive Emissions to atmosphere represent a significant amount of plant losses. Regulatory requirements covering Fugitive Emissions exist in many countries and therefore a leak reduction program should be implemented. Fugitive Emissions also represent financial losses to the business as well as potential damage to the environment. 1 SCOPE The purpose of this Information is to provide Engineers with guidance on the reduction and monitoring methods for Fugitive Emissions. This document does not summarize legal requirements; however, the relevant regulatory requirements that apply should be complied with. 2 DEFINITIONS 2.1 Fugitive Emission Any chemical or mixture of chemicals in any physical form that represents an unanticipated or spurious leak from anywhere on an industrial site. 3 REDUCTION OF FUGITIVE EMISSIONS The possibility of Fugitive Emissions can be reduced if consideration is given to the following generic points when maintenance work is being carried out. (a) (b) (c) (d) Ensure the correct specification of the equipment. Follow the installation procedures and relevant good practices. Ensure the correct level of competence of personnel. Ensure the correct start-up procedures are adhered to. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com
  4. 4. The following measures can be taken to further reduce Fugitive Emissions. 3.1 Valves Valve gland leaks represent the largest source of Fugitive Emissions in process areas. The contribution of individual valves varies widely; those operated most frequently (control valves, actuated valves) will usually have the highest leak rates. Rising stem valves such as gate and globe valves are generally worse than quarter turn valves such as ball or plug valves. Remotely located valves, whose maintenance and monitoring are difficult, tend to have high leak rates. The highest emission rates recorded are on valves in gaseous service, followed by valves on light liquid service. Valves on heavy liquid service usually have very small losses. Fugitive Emissions can be practically eliminated with a sealed metal bellows and a downstream safety gland or equivalent sealing systems and effectively reduced with modern packing materials such as PTFE, aramid or graphite. The material needs to be suitable for use with the process conditions (e.g. pressure, temperature, fluid handled). It is normal to re-tighten the gland at least two or three times before the valve needs re-packing, however, to prevent damage to the packing or valve ensure the glands are: (a) (b) Tightened gradually and evenly. Not over tightened. 3.2 Machine Seals 3.2.1 Pumps Fugitive Emissions from pumps can be controlled effectively with the aid of: (a) (b) (c) (d) (e) Canned motor pumps. Magnetic drive pumps. Multiple mechanical seals with quench or buffer media. Multiple mechanical seals with a dry seal on the atmosphere side. Hermetically tight PD pumps such as diaphragm and bellows pumps. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com
  5. 5. The effectiveness of a buffer media system should be monitored, with leakage losses discharged to a closed system. Secondary containment seals can include low technology solutions such as packing rings, lip seals and throttle bushings and high technology solutions such as dry-running contacting mechanical seals, pressure-activated stand-by mechanical seals and non-contacting mechanical seals. Fugitive Emissions from pump seals can be kept to a minimum by ensuring: (a) (b) (c) Vibration and cavitation are avoided. Correct operation of buffer / barrier systems. Buffer / barrier fluid circulation is established prior to starting the pump. Correct installation has a profound influence on the life and performance of shaft seals. 3.2.2 Compressors Fugitive Emissions from compressors can be reduced effectively with multiple sealing systems. In this case the emission of product from wet sealing systems is prevented by a buffer liquid and from drying sealing systems, for instance, by using an inert gas quenching medium or extracting the leaking product into a gas collection system. 3.3 Remakable Joints In remakable joints the seal is static and therefore they have a low leak frequency. The combination of high population and low leak frequency means that it may not be cost effective to introduce a systematic inspection and maintenance program. For instance, most US regulations require the repair of a leaking connection when discovered, but do not mandate periodic inspection to find leaks. Stress relaxation of gaskets can occur as a result of time, pressure, temperature or creep. Occasionally, the bolts may loosen as a result of vibration. As a result flanged joints should be routinely inspected and re-torqued or remade as appropriate. To reduce Fugitive Emissions from flanged joints good jointing practice should be adopted. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com
  6. 6. 3.4 Pressure Relief Devices Pressure relief devices are an often-overlooked source of Fugitive Emissions as they are designed to release process fluid under certain conditions. However, it is wrongly assumed that this is the only time when emissions occur. The potential causes of leakage from relief valves are chattering or popping (a condition that occurs when the system pressure comes close to the set pressure of the valve); improper re-seating of the valve after a relieving operation; and corrosion or degradation of the valve seat. To reduce Fugitive Emissions from safety relief valves, a suitably specified bursting disc should be installed in the inlet line to the safety relief valve. Consideration should be given to venting safety relief valves in gaseous service to recovery or flare 4 MONITORING OF FUGITIVE EMISSIONS Monitoring programs known as LDAR (Leak Detection and Repair) are considered good practice (and a legal requirement in some countries). To display a level of compliance, these programs are as a minimum, required to demonstrate that: (a) A register of potential leak sources is maintained, and existing leak sources are tagged. (b) Monitoring is undertaken at regular, defined intervals and recorded in the register. (c) Action is taken to reduce leakage. A method of weatherproof tagging should be used on any equipment found to be leaking. The tag should correspond with information logged in the register of potential leak sources, such as the equipment’s ID number, the part leaking, ppm and date found. The tag should remain in place until the equipment is repaired, after which it should be removed and the date repaired recorded in the register of potential leak sources. A ‘two-tag’ system is not critical but can be used to differentiate between equipment with existing leaks and equipment that frequently leaks and requires more frequent monitoring. Further information on leak monitoring can be found on the US Environmental Protection Agency (EPA) website www.epa.gov Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com
  7. 7. Minimum suggested monitoring intervals: (1) Accessible components should be inspected quarterly. (2) Inaccessible components should be inspected annually. (3) Pressure relief devices should be inspected within 14 days after every functional pressure release. The inspection frequency for accessible components, except pumps and compressors, may be changed from quarterly to annually provided the equipment in question has given leak free service for 1 year. 4.1 Management System A management system is key to a successful reduction of Fugitive Emissions. A recommended system would be a database which would allow downloading of emissions data, generation of maintenance work orders for leaking components, accurate and timely reports indicating compliance within guidelines and regulations. 5 FURTHER INFORMATION 5.1 Related External Publications EEMUA publication 195: Compendium of Information Sheets on Topics Related to Pressure-Containing Equipment: Information Sheet 22 ''Fugitive Emissions from Piping Systems and Other Equipment' . Envirowise publication GG71: Guide for Cost-effective Reduction of Fugitive Solvent Emissions. EPA Code of Federal Regulations, Title 40, Part 60, Appendix A. Reference Method 21 “Determination of volatile organic compound leaks”. ESA European Emission Legislation: “A Guide to legislation covering the control of fugitive emissions in Europe”. ESA Publication No 012/00. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com
  8. 8. 5.2 Related Internet Sites www.europeansealing.com www.epa.gov www.eemua.co.uk www.environment-agency.gov.uk www.envirowise.gov.uk - European Sealing Association (ESA) Homepage - US Environmental Protection Agency (EPA) Homepage - EEMUA Homepage (Europe) - Environment Agency Homepage (UK) - Environmental Technology Best Practice Program (UK). Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com
  9. 9. Refinery Process Stream Purification Refinery Process Catalysts Troubleshooting Refinery Process Catalyst Start-Up / Shutdown Activation Reduction In-situ Ex-situ Sulfiding Specializing in Refinery Process Catalyst Performance Evaluation Heat & Mass Balance Analysis Catalyst Remaining Life Determination Catalyst Deactivation Assessment Catalyst Performance Characterization Refining & Gas Processing & Petrochemical Industries Catalysts / Process Technology - Hydrogen Catalysts / Process Technology – Ammonia Catalyst Process Technology - Methanol Catalysts / process Technology – Petrochemicals Specializing in the Development & Commercialization of New Technology in the Refining & Petrochemical Industries Web Site: www.GBHEnterprises.com

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