1 / 18

Hydrogen Safety System Summary

Hydrogen Safety System Summary. Elwyn Baynham, Tom Bradshaw , Yury Ivanyushenkov Applied Science Division, Engineering and Instrumentation Department RAL. MICE Collaboration Meeting, Osaka, August 1-3, 2004. Scope. Status of hydrogen absorber and system safety Hydrogen system:

avery
Download Presentation

Hydrogen Safety System Summary

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Hydrogen Safety System Summary Elwyn Baynham, Tom Bradshaw , Yury Ivanyushenkov Applied Science Division, Engineering and Instrumentation Department RAL MICE Collaboration Meeting, Osaka, August 1-3, 2004

  2. Scope • Status of hydrogen absorber and system safety • Hydrogen system: • - changes in the system according to the Safety Review Panel recommendations; • - ongoing work on safety issues; • Hydrogen absorber/system operation: • - instrumentation and control. • Hydrogen R&D

  3. Status of hydrogen absorber and system safety Safety = Safe Design + Safe Operation • Operation: • Operation analysis - started • Safety system analysis - started • R&D stage - to be done • Operation manual - to be written • Design: • Internal safety review - passed • ( many useful comments, response is ready) • Preliminary HAZOP - done • Instrumentation - to be • implemented Final safety review – to be passed

  4. Changes in MICE hydrogen system • AFC Safety Review Panel recommendations are implemented: • Buffer vessel is removed from venting path. • Vent manifold is added. The manifold is filled with nitrogen. • Venting lines are separated. • Other changes: • Buffer vessel is added in between absorber vessel and hydride bed: • - together with liquid hydrogen vessel and hydrogen condensation pot forms • a quasi-closed system; • - improves time response of safety devices in case of catastrophic failure. • Ventilation system is removed. Most of the equipment is now sits • under hydrogen extraction hood.

  5. H2 Detector H2Detector MICE hydrogen system High level vent High level vent Vent outside flame arrester Non return valve Vent manifold Vent manifold 0.1 bar Hydrogen zone 2 Extract hood VP2 PV8 P1 P Metal Hydride storage unit (20m3 capacity) P PV7 P PV2 PV1 Chiller/Heater Unit 1 bar Tbed Buffer vessel Hydrogen supply PV3 1 m3 PV4 P Fill valve P HV1 Pre-cooling Out In P2 P 0.5 bar Liquid level gauge 0.9 bar P3 HV2 Internal Window P P Purge valve P P P LH2 absorber Safety windows Vacuum Purge valve HV3 Vacuum vessel 0.9 bar Nitrogen supply PV6 Helium supply 0.5 bar VP1 Pressure gauge Pressure relief valve Non-return valve Pressure regulator Bursting disk Valve P P Vacuum pump VP

  6. Safety issues: Ongoing work • Pressure rise rate calculations • Valves • Hydrogen sensors • Control

  7. Operation issues: Ongoing work • Operation from cryocoolers • Instrumentation and control

  8. Hydrogen absorber instrumentation • Instrumentation to be implemented into absorber design: • Hydrogen level sensor/s: • - their functions (what do we need them for)? • - continuous/ discrete? • - how many and where? • Temperature sensors: • - their functions ? • - how many and where?

  9. Hydrogen level sensors Continuous level sensor Point level sensors

  10. Cryogenic liquid level sensors from AMI The capacitance-based liquid level sensor, used in conjunction with the Model 185 and 186, is manufactured of stainless steel tubing. Upon request, special assembly techniques can be applied for sensors required for liquid oxygen or hydrogen measurement _ including minimization of oils during construction and no use of epoxies. Sensors can be supplied in single-section overall lengths of up to 30 feet. Multi-section lengths in excess of 50 feet are available upon request. Three standard sensor mounting configurations are available. The typical configuration includes a hermetically sealed BNC connector with an adjustable 3/8" male NPT nylon feed-through. For higher pressure or vacuum applications, a welded stainless steel 3/8" male NPT fitting or conflat flange fitting is available. Twelve feet of connecting coaxial cable and in-line oscillator/transmitter are included with the sensor. With additional cable the sensor can be remotely mounted over 500 feet from the instrument without effecting performance. Sensor options include: 1. Rugged service construction 1/2" or 3/4" OD 2. Miniature sensors of 3/16" and 1/4" OD 3. Radius bends up to 90° 4. Capacitance or RTD point sensing elements Custom sensors are available from AMI to meet your individual

  11. Level sensor implementation Continuous level sensor Connector required (Swagelok VCR Metal gasket face seal fittings ?) Can a sensor be manufactured to this shape ?

  12. What is known about metal hydride tank Table 1 The specification of the MH tank for RAL Hydrogen Storage Capacity20 Nm3 Tank number/system1 Tank Description: Heat Transfer MediumWater MH Weight 155kg Tank StructureShell & Tube type Dimensions φ216.3×L1600（mm） ( not include attachments ) Tank Total Weight220 Kg Operating Condition: Charging Gas ComponentHydrogen of 99.99% purity Charging Gas Pressure1.2 barA Hydrogen Charging Rate70NL/min (up to 90% of Storage Capacity) Discharging Gas Pressure1.2 barA Hydrogen Discharging Rate70NL/min (up to 90% of Storage Capacity) Utility Requirements: Cooling MediumWater Below -10℃ （At 20L/min） Heating MediumAbove 20℃ （At 20L/min） Design Code（AD Merkblaetter ) Certification（Declaration of Conformity to Pressure Equipment Directive 97/23/EC Certified by a Notified Body） REFERENCE

  13. What is known about metal hydride tank (2) Fig.1 Schematics and dimensions of the MH tank

  14. What is known about metal hydride tank (3) Fig.2 P-C-T curves of metal hydride for RAL

  15. What is known about metal hydride tank (4) Annotation by JSW: Attached please find the temporary specification of a 20Nm3 metal hydride (MH) tank, its sketch and the pressure-composition-temperature diagram of the candidate MH alloy. It would be better to explain the temperatures and pressures on charging and discharging hydrogen, referring to the PCT diagram. As you can see in the diagram (Fig. 2), it is possible for the alloy to absorb hydrogen gas almost to its maximum capacity at 0 degC if the pressure of hydrogen gas is maintained at 0.12 MPa. However, we are not yet sure of the influence of pressure loss inside the tank under such a negative pressure region. So, at the moment the charging temperature is specified to be below -10 degC with 0.12 MPa of charging pressure (See Table 1.). Then, you can see in the diagram (Fig. 2) that the MH alloy can discharge almost all the hydrogen at +20 degC if the pressure is maintained at 0.17 MPa. To be on the safer side, the discharging temperature is specified to be "above" +20 degC (See Table 1.). This means that the maximum internal pressure of the MH tank is likely to be reached during the hydrogen gas holding period if the water is stopped and the surrounding temperature increases. However, even at +30 degC, the expected internal pressure is not so high, approximately 1 MPa. As a matter of fact, there will be an unknown factor, i.e., how accurately we could control the materials properties when we newly manufacture an MH alloy. Due to slight variations in the chemical composition and other manufacturing parameters, the equilibrium temperature could vary by up to 5 degC for the same pressure. This could cause further changes in the charging/discharging temperatures and consequently the internal pressure. Since the relative plateau positions do not change, please assume that a difference of more than 30 degC is needed between the charging and discharging temperatures for the given charging and discharging pressures.

  16. Hydrogen R&D • Conceptual question: a small-scale rig vs. a full-scale prototype ? • Decision: go for a full-scale system which later will be used in MICE. • R&D goals: • Establish the working parameters of a hydride bed in the regimes of storage, absorption and desorption of hydrogen. • Absorption and desorption rates and their dependence on various parameters such as pressure, temperature etc. • Purity of hydrogen and effects of impurities. • Hydride bed heating/cooling power requirements. • What set of instrumentation is required for the operation of the system? • Safety aspects including what is the necessary set of safety relief valves, sensors and interlocks.

  17. Hydride system test rig High level vent High level vent Vent outside flame arrester Non return valve Vent manifold Vent manifold 0.1 bar Hydrogen zone 2 Extract hood VP2 PV8 P1 P Metal Hydride storage unit (20m3 capacity) P PV7 P Mass spectrometer M. F.M. PV2 PV1 Chiller/Heater Unit 1 bar Mass flow meter Tbed Buffer vessel Hydrogen supply PV3 1 m3 PV4 P Fill valve P HV1 Coolant Out In P2 P 0.5 bar 0.9 bar P3 HV2 P P Purge valve P P P H2 Detector H2Detector Test absorber assembly Purge valve HV3 0.9 bar Nitrogen supply PV6 Helium supply 0.5 bar VP1 Non-return valve Pressure gauge Pressure relief valve Pressure regulator Bursting disk Valve P P Vacuum pump VP Tchill

  18. Next steps • Finish pressure rise rates calculations • Select safety devices • Control system diagram • Instrumentation defined and implemented into design • Hydrogen R&D: • - find suitable place for hydrogen test area (MICE hall ?); • - timetable depends on funding • but would like to setup test rig in 2005.

More Related