From food to heating, hydrogen is widely used. And it is fast becoming an important alternative energy. But it is mainly in the industrial sector that it is used. Let us find out what its applications are, and what are the risks.
The recent Hydrogen Expo 2023, held in Piacenza in May, offered an opportunity for some further reflection on the important topic of hydrogen and its industrial applications. From boilers for the home to forklift trucks, from generators to furnaces for large energy-intensive industries to cars, even racing cars. All strictly powered by hydrogen. This is what could be admired in the halls of Piacenza Expo. A sign of the great interest in an element, namely hydrogen, destined to profoundly change our lives.
For decades, it has been used mainly by the chemical and refining industries. For example, it is a key raw material needed to produce ammonia (NH3), an important part of fertilisers used in agricultural industries around the world, as well as a cheap and environmentally friendly refrigerant (R-717).
In petroleum refining, hydrogen is commonly used in the hydrocracking process to obtain products such as petrol and diesel. In the oil industry, it is also used to remove contaminants such as sulphur and to create methanol (CH3 OH). Biofuel producers also use hydrogen to produce hydrotreated vegetable oil (HVO) for use as renewable diesel.
However, as we said, hydrogen is now used in many other areas and is constantly increasing. In the food industry, for example, it is used to transform unsaturated fats into saturated oils and fats, including hydrogenated vegetable oils such as margarine and spreads.
In metalworking, it is used in processes such as metal alloying, where it is introduced into molten metals to improve properties such as mechanical strength and corrosion resistance. In welding processes, it is mainly found in atomic hydrogen welding (AHW), where it is split into atoms through an electric arc. The atoms combine to create a flame which melts the metals. Another application is in the production of flat glass, where hydrogen and nitrogen prevent oxidation and defects during the manufacturing process. In electronics, hydrogen is used to create semiconductors, LEDs, displays, photovoltaic segments and other components. Finally, in the medical industry, it is used to obtain hydrogen peroxide (H2O2), a commonly used antiseptic. Recently, hydrogen has also been studied as a therapeutic gas for a number of different diseases.
Hydrogen fuel cells
Hydrogen is currently also used in fuel cells to generate electricity and power vehicles. Specifically, hydrogen fuel cells produce electricity by combining hydrogen and oxygen atoms. Hydrogen reacts with oxygen through an electrochemical cell, similar to a battery, to produce electricity, water and small amounts of heat. A fuel cell can be two to three times more efficient than a petrolpowered internal combustion engine.
Hydrogen fuel cells are used to power the electrical systems of spacecraft, and to provide electricity on earth. Small fuel cells have been developed to power electronic devices such as laptops and mobile phones, while several manufacturers have developed fuel cells to power on-road vehicles. Fuel cells can also potentially provide electricity for emergency power in buildings, and for remote locations with no connection to power grids.
The market is huge. Suffice it to say that at the end of 2022, the US had about 205 fuel cell power generators operating in 147 plants, with a total electrical generation capacity of about 350 MW. Most fuel cells in use employ natural gas as a source of hydrogen, but four of them use biogas from wastewater treatment. Interest in hydrogen as an alternative transport fuel stems mainly from its potential to power fuel cells in zeroemission vehicles.
Power generation and heating of rooms
The combustion of hydrogen to produce electricity and for heating rooms is a potential use of pure gas or hydrogen-rich mixtures with natural gas. However, the use of hydrogen and hydrogen mixtures in existing natural gas distribution infrastructure and combustion equipment poses a number of problems related to material compatibility and combustion characteristics. Progress has been made with the modification of natural gas burners in commercially available combustion turbines to accommodate high-hydrogen mixtures (up to 100 per cent hydrogen), but continued research, development and demonstration is required before hydrogen qualifies for industrial-scale power generation. Today, several power plants are exploring the use of hydrogen to supplement or replace natural gas. This is also because it can be stored in gaseous form in large volumes in natural geological formations: salt caverns, lined hard rock caves, depleted oil and gas fields, and aquifers.
Hydrogen gas can also be stored in relatively smaller volumes in pressurised, fixed or portable tanks and in dedicated hydrogen pipeline infrastructures. Gaseous storage is currently the most common and most likely option for expanding hydrogen storage for most uses as an energy source.
The safety issue
The properties of hydrogen raise the fundamental issue of safety. This was discussed at the three meetings organised by G.I.S.I., PBN and 3p SAFETY held during Hydrogen Expo 2023. The titles were respectively: ‘Hydrogen leak risk: how to detect it with the right technologies’, ‘The great danger of being green in 2023: hydrogen. How to harness an explosive gas to reduce pollution’ and ‘Safe and sustainable hydrogen: experiences and case histories. How to introduce new technologies safely: application examples, standards, authorisation processes, mistakes to avoid’.
Source: Controllo e Misura by Publitec
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