Oxygen Pipeline and Piping Systems

Transcription

1 Oxygen Pipeline and Piping Systems Sunil KHER Air Liquide Oxygen Safety Seminar

2 Disclaimer All publications of GIA or bearing GIA s name contain information, including Codes of Practice, safety procedures and other technical information that were obtained from sources believed by GIA to be reliable and/ or based on technical information and experience currently available from members of GIA and others at the date of the publication. As such, we do not make any representation or warranty nor accept any liability as to the accuracy, completeness or correctness of the information contained in these publications. While GIA recommends that its members refer to or use its publications, such reference to or use thereof by its members or third parties is purely voluntary and not binding. GIA or its members make no guarantee of the results and assume no liability or responsibility in connection with the reference to or use of information or suggestions contained in GIA s publications. GIA has no control whatsoever as regards, performance or non performance, misinterpretation, proper or improper use of any information or suggestions contained in GIA s publications by any person or entity (including GIA members) and GIA expressly disclaims any liability in connection thereto. GIA s publications are subject to periodic review and users are cautioned to obtain the latest edition. GIA GIA grants permission to reproduce this publication provided the Association is acknowledged as the source Oxygen Safety Seminar

3 Contents Introduction The Fire Triangle Ignition Mechanism Selection of Metals Selection of Non-Metals Piping Systems Pipe Equipment Cleaning Methods Conclusion Oxygen Safety Seminar

4 Introduction Based on EIGA document - IGC 13/12/E Purpose Reinforce understanding of those engaged in the safe design, operation, and maintenance of gaseous oxygen transmission and distribution systems Scope Metal oxygen pipelines Distribution piping systems O2 piping of an ASU external to cold box Exclusions Oxygen cylinder filling plants Medical oxygen piping installations Cold box internal piping Oxygen compressor units, Liquid oxygen vaporizers, bulk oxygen facilities Oxygen Safety Seminar

5 The Fire Triangle Mitigative actions - Minimize severity of oxidizer by reducing oxygen pressure, temperature and concentration if possible Minimize severity of fuels by using burn resistant alloys Minimize severity of ignition by reducing / eliminating particle impact and adiabatic compression and limiting gas velocities Oxygen Safety Seminar

6 Ignition Mechanisms Particle Impact Adiabatic Compression Promoted Ignition Thermal Ignition Friction Impact Arcing Oxygen Safety Seminar

7 Particle Impingement Selection of Metals Impingement occurs when the flow stream changes direction abruptly or when the presence of eddies leads to the impact of particles with the system walls Impingement Sites Tees (Butt & Socket), Elbows (Socket), Short radius elbows, Reducers, 8D pipe length downstream of a let down etc. Valves, strainers, filters, orifices, silencers etc. Non-Impingement Sites Straight pipe runs Oxygen Safety Seminar

8 Selection of Metals Exemption Pressure & Velocity Exemption pressure is the maximum pressure at which a material is not subject to velocity limitations in oxygen enriched atmospheres where particle impingement may occur. This is also a function of the thickness of the pipe. Material Examples Showing Min Thickness & Exempt Pressures SS 304 / mm (13.8 bara) SS 304 / mm (25.8 bara) Inconel 3.18 mm (69 bara) Monel mm (206.8 bara) Oxygen Safety Seminar

9 Selection of Metals Velocity limitations for Impingement sites P < 3 bara No velocity consideration 3 bara < P < 15 bara V=30 m/sec 15 bara < P < 100 bara P*V=450 bara* m/sec 100 bara < P < 200 bara V=4.5 m/sec Impingement Velocity Curve Velocity (m/sec) Carbon Steel Stainless Steel (3.18) Stainless Steel (6.35) Inconel (3.18) Monel (0.762) Pressure (BarA) Oxygen Safety Seminar

10 Selection of Metals Velocity limitations for Non-Impingement sites P < 3 bara No velocity consideration 3 bara < P < 15 bara V=60 m/sec 15 bara < P < 100 bara P*V=800 bara* m/sec 100 bara < P < 200 bara V=8.0 m/sec Non-Impingement Velocity Curve CS (6.35) SS (6.35) 70 Velocity (m/sec) SS (6.35) Inconel (3.18) Monel (0.762) Pressure (BarA) Oxygen Safety Seminar

11 Selection of Non-Metals Oxygen Index (OI) Heat of Combustion Auto Ignition Temperature (AIT) Material Examples PTFE FEP or PCTFE Elastomers Polymers Ceramics and Glass Note 1 - Design temp. should be considered when selecting non metals. Note 2 - Fluorinated polymers may release toxic gases when they burn. Oxygen Safety Seminar

12 Selection of Non-Metals Best Practices to be followed when designing a system containing non-metals Minimize non-metals Avoid locating non-metals directly in the gas stream Prevent excessive movement of the component Consider heat dissipation Ensure stability of materials Ensure electrical continuity Cleaning Oxygen Safety Seminar

13 Lubricants Use ONLY qualified oils and greases. Try design to function without lubrication. Minimize Use Incorporated for life Oxygen Safety Seminar

14 Underground Piping Systems All welded construction Externally coated Cathodic protection Adequately buried Distinctively Marked Piping Systems Aboveground Piping Systems Good mechanical design Painted Electrically insulated joints with underground cathodic protection system. Electrical Continuity Careful Routing Colour Coded Oxygen Safety Seminar

15 Piping Systems Bypass Piping Piping upstream of vents and bleeds Piping downstream of vent valves Piping downstream of pressure letdown sites kets Thread Sealants Dead Ends VENT VALVE BYPASS VALVE LET DOWN PRV ISOLATION VALVE DEAD END PRODUCT LINE Oxygen Safety Seminar

16 Valve Classes Isolation Valves Throttling or process control valves Emergency shut-off valves Bypass Valves Vent Valves Oxygen Safety Seminar

17 Valve Types Ball and Plug Valves Butterfly Valves Gate Valves Globe Valves Valves shall be procured from suppliers suitably qualified in oxygencompatible procedures. Oxygen Safety Seminar

18 Pressure Relief Valves Check Valves Conical Strainers Y-Strainers Filters Other Equipment Equipment shall be procured from suppliers suitably qualified in oxygen-compatible procedures. Oxygen Safety Seminar

19 Other Equipment Bursting Discs Flexible Connections Equipment shall be procured from suppliers suitably qualified in oxygen-compatible procedures. Oxygen Safety Seminar

20 Cleaning Methods The cleaning of oxygen pipelines may be accomplished by any one or a combination of more than one of the following methods Chemical cleaning (acid or alkali) and passivation; Pigging; Mechanical scraping; Grit, sand or shot blasting; Dry carbon dioxide ice blasting; Water blasting; Solvent washing; High pressure detergent cleaning; High temperature detergent cleaning; or High velocity gas purge. Oxygen Safety Seminar

21 Conclusion Because of its life sustaining properties, oxygen is often perceived as useful and non-threatening. DO NOT get fooled by this misconception Quote from the Air Liquide World Wide Safety Campaign Video Oxygen Safety Seminar

22 Presentation based on EIGA document IGC Doc 13/12/E : Oxygen Pipeline and Piping Systems Oxygen Safety Seminar