Liquid Hydrogen Application Overview:
🟦 1) Hydrogen can be stored as compressed gas, liquid hydrogen, hydrides, adsorbed hydrogen, and reformed fuels. Liquid hydrogen offers advantages including high hydrogen densities and purity, making it suitable for long-term storage, long-distance transportation, and economic efficiency.
🟦 2) Physical properties of hydrogen:
Lower heating value = 118.8 MJ/kg
Higher heating value = 143 MJ/kg
Boiling temperature at 1 atm = -253 °C
Melting temperature = -259 °C
Density of gaseous hydrogen at 0 °C = 0.08987 kg/m3
Density of liquid hydrogen at -253 °C = 70.85 kg/m3
Density of solid hydrogen at -259 °C = 858 kg/m3
Heat capacity of gaseous hydrogen at 0 °C = 14.3 kJ/kg. °C
Heat capacity of liquid hydrogen at °256 °C = 8.1 kJ/kg. °C
Heat capacity of solid hydrogen at °259.8 °C = 2.63 kJ/kg. °C
Liquid-to-gas expansion ratio at atmospheric condition = 1:848
🟦 3) Liquid Hydrogen Boil-Off
The phenomenon of liquid hydrogen vaporising during storage is called boil-off, which results in energy and hydrogen loss. Factors affecting boil-off include thermal insulation, tank dimensions, and the hydrogen ratio. If the vaporised hydrogen is not released, the pressure inside the tank will increase.
🟦 4) Liquid Hydrogen Boil-Off mitigation:
- Isomer change acceleration from ortho- to para-hydrogen during liquefaction,
- The surface-to-volume ratio minimization of the vessel (e.g. spherical vessel),
- Vessel super insulation to reduce the heat transfer from the environment,
- Cryocooler utilization.
- A combination of liquid hydrogen storage vessels and metal hydrides, where metal hydride absorbs evaporated liquid hydrogen,
- Cryocoolers and passive insulation have also been developed to minimize boiloff
- Shielding the liquid hydrogen vessel wall using liquid nitrogen,
- Reliquefying the liquid hydrogen boil-off where the liquefaction plant and liquid hydrogen storage vessel are close.
- boil-off gas can be used for power generation and fuel for tankers and trucks.
🟦 5) Liquid Hydrogen Standards:
International Standardization Organization (ISO)
ISO/TR 15916
ISO 13984
ISO 13985
United Kingdom
- Dangerous Substances and Explosive Atmosphere Regulations (DSEAR),
- Control of Major Accident Hazard (COMAH),
- Pressure Equipment Regulations (PER),
- Carriage of Dangerous Goods (CDG) regulations.
- ATEX 137 (Directive 99/92/EC)
- ATEX 95 (Directive 94/9/EC)
United States
- NFPA 2
- NFPA 55
- OSHA Process and Safety Management (OSHA PSM)
- EPA Risk Management Plan (EPA RMP) Guidance
- CG G-5.4
- CGA G-5.5
- CGA P-28
- CGA P-12
- CGA PS-17
- CGA H-3
- IFC 3005
- IFC 2209.3
- IFC 3203
- IFC 3204
- IFC 3205
- IFC 2204
- IFC 2209
- SAE AS6679
- NFPA 30A
China
- GB/T 34583
- GB/T 34584
- GB/T 29729
Source: see post image
This post reflects my personal perspective and is for educational purposes only.
👇 What other codes, standards or guidelines have you used for liquid hydrogen application?
