Hydrogen is the simplest and most abundant element in the universe. It is found as a gas in stars and planets, as well as in various chemical and organic compounds, such as water. When transformed into liquid hydrogen , it acquires unique properties that make it useful in various applications, especially in industrial and energy sectors.
In this article, we explain in detail what liquid hydrogen is, how it is produced, its main characteristics and the different ways in which it can be stored and used.
Hydrogen abundance
Hydrogen makes up more than 70% of the visible matter in the universe, making it the most abundant element. It is also fundamental in processes such as the formation and evolution of stars. Although abundant in the universe, hydrogen in its molecular form (Hâ‚‚ ) is difficult to find in its pure state on Earth; it is usually combined with other elements, as in the case of water (Hâ‚‚O ) or in hydrocarbons such as petroleum and natural gas.
Hydrogen has several isotopes, which vary according to the number of neutrons in their nucleus:
- Protium (1H): The most common form of hydrogen, composed of a single proton and no neutrons.
- Deuterium (2H): It has one neutron and one proton, making it slightly heavier than protium.
- Tritium (3H): It contains two neutrons along with the proton, making it even heavier and more radioactive.
Main characteristics of liquid hydrogen
Hydrogen turns into a liquid state when it is cooled to extremely low temperatures, specifically -252,87 °C (or -423,17 °F). This process, although expensive, is essential to facilitate its storage and transportation, since liquid hydrogen occupies much less volume than its gaseous state.
Among the most notable characteristics of liquid hydrogen, we find:
- Low boiling point: Because it is so cold, it can cause frostbite or hypothermia if handled without proper precautions.
- choking hazard: If liquid hydrogen or its vapors are inhaled, it can replace oxygen in the lungs, which can cause suffocation.
- Ice formation:Due to its low temperature, liquid hydrogen can form ice on the valves and openings of your tanks, which can cause dangerous blockages.
- Continuous evaporationLiquid hydrogen is constantly evaporating, generating hydrogen gas. This gas must be purged in a controlled manner to avoid mixing with air and possible explosions.
How Liquid Hydrogen Is Stored
Storing hydrogen is one of the biggest challenges for its widespread use as an energy source. Given its tendency to evaporate and its flammable characteristics, storage systems must be robust and safe.
There are two main forms of hydrogen storage depending on its use:
- Stationary storage systems: Used in large-scale applications such as industrial plants or power generation systems. These systems are usually less restrictive in terms of space and weight.
- Storage systems for transport: The challenge here is to keep hydrogen in a state that allows for easy transport without compromising vehicle autonomy. Hydrogen-powered vehicles must be able to store sufficient quantities, while respecting safety and efficiency criteria.
The transportation industry is at the forefront of developing more efficient and safer storage methods, as liquid hydrogen offers one of the best solutions for clean mobility compared to traditional fossil fuels.
In addition, new storage technologies are being investigated, such as the use of glass microspheres, zeolites or metal hydrides, which seek to improve the safety and efficiency of hydrogen storage in both its liquid and gaseous states.
Uses and applications of liquid hydrogen
Liquid hydrogen is a versatile energy source that can be applied in different industrial sectors:
- Industrial cooling: Its high efficiency makes it an excellent refrigerant gas. Thanks to its ability to transmit heat efficiently, hydrogen is used in engine cooling systems and other industrial equipment.
- Alternative fuel:Hydrogen is key to the development of fuel cell vehicles, which allow for cleaner transportation, with a range similar to combustion vehicles, but without generating polluting emissions.
- Aerospace industry:Thanks to its ability to store and release large amounts of energy, hydrogen has been used as rocket fuel for decades.
- Food productionIn the food industry it is used in processes such as the hydrogenation of fats to improve the stability and shelf life of products such as margarine.
In general, liquid hydrogen is essential in sectors where a clean energy source that does not emit CO2 is required . Its low environmental impact makes it an increasingly popular option for decarbonizing industrial and transportation activities.
Hydrogen production
Hydrogen can be produced using various methods, some cleaner than others. The most common process is natural gas reforming, which, while effective, emits a considerable amount of CO2 . However, more sustainable methods are now being explored, such as water electrolysis, a process that, when powered by electricity from renewable sources, does not emit greenhouse gases.
Three main categories of hydrogen production can be distinguished, colour-coded according to their environmental impact:
- Gray hydrogen: It is produced from fossil fuels, usually natural gas, and generates carbon dioxide emissions.
- blue hydrogen: Similar to grey hydrogen, but with the difference that CO emissions2 are captured and stored.
- Green hydrogen: The cleanest of all. It is produced by electrolysis of water using renewable energy, without generating carbon emissions.
The future of hydrogen production is linked to the promotion of renewable energies and water electrolysis. As an inexhaustible source of energy with applications in various fields, green hydrogen plays a fundamental role in the transition towards a more sustainable economy.
With a long-term vision, several countries are investing in infrastructure for green hydrogen production. Spain, for example, has launched its own roadmap to develop an economy based on renewable hydrogen, with the goal of significantly reducing CO2 emissions in the coming decades.
Liquid hydrogen is seen as a promising solution in the transition towards cleaner and more sustainable energy. Its versatility and ability to be stored and transported in large quantities, combined with its potential to decarbonise industry and transport, make it a key element in the future of energy.