What distinguishes hydrogen from fossil fuels in terms of properties? And how does it behave?
Hydrogen is non-toxic, and the lightest of all gases.
Hydrogen will rise very quickly up in the air, compared to, for example, petrol vapor which stays longer at the ground.
Hydrogen is very reactive and is almost never found in its pure form in nature. Hydrogen has a very high gravimetric energy density, but a low volumetric energy density.
Hydrogen self-ignites at high temperatures, but has a very low ignition energy, and is flammable when mixed with air over a wide range.
A hydrogen flame is almost invisible in daylight.
Hydrogen burns very quickly, and in closed spaces this can lead to rapid pressure build-up and explosions.
What are some of the challenges of using hydrogen in terms of safety? What are the benefits?
The biggest challenges with hydrogen are the danger of explosion and the fact that it is easily ignited. The advantage is that a leak of hydrogen gas rises very rapidly up into the air and will quickly be diluted.
What is the difference between emissions of hydrogen gas and emissions of liquid hydrogen? What must be taken care of?
Release of liquid hydrogen will freeze surrounding gases in the air, and this can "trap" the hydrogen at the ground. The hydrogen can stay for a while close to the ground, and in some cases it can even move horizontally, before it warms up and disappears.
When using liquid hydrogen, care must be taken to remove ignition sources in a larger radius around, for example, ventilation masts. Care must also be taken that materials around potential ventilation points can withstand the extremely low temperatures.
The pressure in a container is 735 torr. Convert the pressure to atmospheres and pascals.
Last changeda year ago
