Hydrogen was discovered in 1766 by British scientist Henry Cavendish. By chance he discovered that water (H20) consists of Hydrogen (H) and Oxygen (O).
Hydrogen comes from the Latin Hydrogenium which literally means “making water”. This is why the chemical symbol is H.
Hydrogen is the first element in the periodic table: no other element is lighter; no other element is more abundant in the universe. Hydrogen is pure energy. Perhaps the best example is the Sun, 92.1% of which is Hydrogen.
Hydrogen is a diatomic element, meaning that in its liquid and solid states, hydrogen naturally forms into pairs of atoms, which is why hydrogen is often referred to as “H2”. Hydrogen is the lightest element, yet it has the highest energy content per unit weight of all fuels. Hydrogen’s energy density is 120.1 MJ/kg, which is three times greater than that of gasoline.
The video shows the Hydrogen Properties and Behaviour.
Gaseous Hydrogen Properties and Behaviors
Some basic properties and behaviors of gaseous hydrogen are highlighted on this page. For more information on hydrogen properties, see Hydrogen Compared with Other Fuels.
- Hydrogen is a gas in ambient conditions.
- It is the lightest molecule in the universe.
- It is 14 times lighter than air, so it rises at almost 20 meters per second (71 Km per hour) and disperses rapidly. This buoyancy is a built-in safety advantage in an outside environment.
- It is colorless, odorless, tasteless, and undetectable by human senses.
- It is non-toxic and non-poisonous; however, it can be an asphyxiant.
- Like any flammable fuel, hydrogen can combust. But hydrogen’s buoyancy, diffusivity and small molecular size, make it difficult to contain and create a combustible situation.
In order for a hydrogen fire to occur, an adequate concentration of hydrogen, the presence of an ignition source and the right amount of oxidizer (like oxygen) must be present at the same time.
It is non-corrosive, but as with other cryogenic liquids, it can embrittle some metals (i.e., cause deterioration of the metal’s mechanical properties). Today, this phenomenon is well known and hydrogen embrittlement is overcome by using suitable materials and understanding what stresses they can be subjected to (304 or 316 stainless steels, aluminum or copper in hydrogen storage systems and piping)
Source: h2tools.org
Liquid Hydrogen Properties and Behaviors
Some basic properties and behaviors of liquid hydrogen are highlighted on this page. For more information on hydrogen properties, see Hydrogen Compared with Other Fuels.
- Hydrogen can be stored in its liquid state at -253°C and might cause cryogenic burns when not handled properly. Therefore, as per any other cryogenic liquid, Personal Protective Equipment (PPE) is required.
- Hydrogen undergoes a rapid phase change from liquid to gas, so ventilation and pressure relief devices are built into cryogenic hydrogen systems to ensure safety.
- The volume ratio of liquid to gas is 1:848. If you picture a liter of liquid hydrogen, that same amount of hydrogen, existing as a gas, would, theoretically, occupy 848 liters containers (without compression).
If spilled in ambient temperatures, liquid hydrogen will create only a white cloud of water vapor due to the cryogenic temperature condensing the water contained in the surrounding air. Hydrogen gas will quickly diffuse and rise in the air.