- Количество слайдов: 10
MICE Hydrogen System Tom Bradshaw Yury Ivanyushenkov Elwyn Baynham Meeting October 2004 – Coseners House
Baseline layout High level vent Non return valve Vent manifold 0. 1 bar Hydrogen zone 2 Vent outside flame arrester Vent manifold H 2 Detector Extract hood VP 2 PV 8 P P 1 PV 7 P PV 2 Buffer 3 vessel 1 m Hydrogen supply P P PV 1 Metal Hydride storage unit (20 m 3 capacity) 1 bar Tbed PV 3 PV 4 Fill valve P HV 1 Coolant Out In P 2 P 0. 5 bar 0. 9 bar P P 3 P HV 2 Purge valve P H 2 Detector Safety window Nitrogen supply Purge valve HV 3 Absorber window PV 6 Helium supply 0. 9 bar 0. 5 bar VP 1 P Pressure gauge P Pressure regulator Valve Pressure relief valve Non-return valve Bursting disk VP Vacuum pump Chiller/He ater Unit
Hydride bed • Tanks need to be horizontal • Air ingress reduces capacity and oxidises material – oxidation rate is low. • Alloy will become flammable after activation but it needs an ignition source. Checked that there are Activation procedure: a) Pump out absorber b) Heat to 60 -80 C c) Add H 2 to about 1. 2 bar d) Leave to soak for 8 hours no safety issues if there is a catastrophic ingress of air.
Hydride Bed Black lines absorbtion Dotted lines desorbtion Hydride Characteristics 20 l liquid = 16, 000 normal litres gas – will absorb this in under 4 hours
Specification for the Hydride Bed Hydrogen Storage Capacity 20 Nm 3 Operating Condition: Tank Description: Heat Transfer Medium Water MH Weight 155 kg Tank Structure Dimensions 1. 2 bar. A 70 NL/min (up to 90% of Storage Capacity) Discharging Gas Pressure 1. 2 bar. A Hydrogen Discharging Rate 70 NL/min (up to 90% of Storage Capacity) Shell & Tube type φ216. 3×L 1600（mm） ( not include attachments ) Tank Total Weight Hydrogen of 99. 99% purity Hydrogen Charging Rate 1 Charging Gas Component Charging Gas Pressure Tank number/system Utility Requirements: Cooling Medium Water Below -10℃ （At 20 L/min） 220 Kg Heating Medium Above 20℃ （At 20 L/min） Design Code AD Merkblaetter Certification Declaration of Conformity to Pressure Equipment Directive 97/23/EC Certified by a Notified Body）
Effectiveness of Buffer Volume Expected boil-off rate Latent heat 446000 J/kg Power into liquid 10179 W Hydrogen boiled off (kg/s) 0. 0228 23 kg/s Start mass of liquid 1. 544 Liquid density Start pressure (bar) Rgas dt Buffer vol density 300 K kg 70. 288 0. 5 • Assumes mixing of gas - cold from absorber + buffer volume 4157 • Temp in buffer calc on basis of constant Cv - this is optimistic for Tgas ~50 K but pretty good for Tgas >100 K 0. 2 1 0. 08 m^3 kg/m^ 3 relief valve pressure 1. 60 E+ 05 Pa outlet mass flow 1. 20 E 02 kg/s • For large outflow through relief valve the algorithm is not correct because the valve essentially shuts • Buffer volume gives a huge safety margin over just the pipe system with vol ~ 0. 1 m^3 for 50 m of 50 mm dia pipe • The buffer vessel will keep the gas warmer due to its thermal mass - this is not included - it will increase the pressure rise • Typically with 1 m^3 Tgas ~100 K pressure rise rate is 0. 1 bar/sec valve opening time of 0. 1 -0. 2 sec would be OK
Pressure relief valves Tyco (Crosby) valves – key points: • Pilot valves – quick acting • 3% tolerance on set pressure • Closes at 95% of set pressure • Response time is <0. 5 s • Valves re-seat on elastomers • 91&94 valves usable to 20 K (although situated at RT) They also manufacture bursting discs and flame arrestors Feel confident that we have a solution for this.
R&D Process • Next steps are to design layouts in the hall, pipework – test area • Installation of venting system Issue of the test area is still not finalised – is it sensible to test while other work is going on ? May have to make a safety case or find somewhere else. • Design and order cryostat and cryocooler • Order hydride bed • Pressure relief valves • Control system We will be using a cryocooler and perform tests on the control system, condensation rate etc… Main issue is what will the funding profile allow ? ……
Safety Review Process
END Source. D: MICECryogenicsHydrogen. System[Pressure rise buffer. xls]press buffer-2