2019 has been declared by UNESCO as the Year of the Periodic Table. To celebrate, we are releasing a series of blogs about our favourite elements and their importance to the chemical industry. Today’s blog is about the first element in the periodic table, hydrogen!
Hydrogen isn’t just for keeping balloons afloat. Image: Pixabay
Hydrogen (H2) gas has many uses in modern engineering. Scientists are always searching for cheaper, more renewable fuel sources that have a lower negative impact on the environment. Hydrogen was frequently used to generate energy in the past, and this drive for more renewable energy has given hydrogen-derived fuel a new lease of life.
Hydrogen can be used in fuel cells. These act like batteries, generating their energy from a reaction between hydrogen and oxygen (O2). Hydrogen fuel cells have been incorporated into many modern technologies, including automotive. As the reaction occurring only generates heat, electricity and water, fuel cells are significantly better for the environment than many alternatives. Hydrogen is also much cheaper as a commodity that typical fuels.
Hydrogen fuel cells can now be used to power automotive vehicles, including cars!
Engineering cooling systems can use hydrogen. The gases physical properties make it 7-10 times better at cooling than air. It can also be easily detected by sensors. Because of this, hydrogen is used in cooling systems, which are generally smaller and less expensive than other available options.
Hydrogen gas can be used in reactions. The most famous reaction using hydrogen is the production of ammonia (NH3), also known as the Haber process. The Haber process was developed by Fritz Haber and Car Bosch in the early 20th century to fill the need to produce nitrogen-based fertilisers. In the Haber process, atmospheric nitrogen (N2) is reacted with H2 and a metal catalyst to produce NH3.
Nitrogen-based fertilisers are still used today, but ammonia was one of the first to be commercially produced.
Ammonia is a valuable fertilised, providing much needed nitrogen to plants. It was used on a variety of agricultural plants, including food crops wheat and maize, in the 19th and early 20th century.
Chemists undertake other chemical reactions, such as hydrogenation and reduction, that utilise hydrogen, to make commercially valuable products. Some physical properties of hydrogen make it tricky, and often dangerous, to use in industry. However, careful control of conditions allow for its safe use on larger scales.
Hydrogen gas can be explosive, making it often dangerous to use.
Producing hydrogen gas
There are many ways to produce gaseous hydrogen. The four main sources of commercially produced hydrogen are natural gas, oil, coal and electrolysis. To obtain gaseous hydrogen, the fossil fuels are ‘steam reformed’, a process which involves a reaction with steam at high pressure and temperature.
Electrolysis of water is another method that is used in hydrogen production. This method is 70-80% efficient. However, it often requires large amounts of energy, specifically in the form of heat. This heat can be sourced from waste heat produced by industrial plants.
So, whats all this hot air about hydrogen? Source: Tedx Talks
An alternative method for producing hydrogen is via biohydrogen. Hydrogen gas can be produced by certain types of algae. This process involves fermentation of glucose. Some hydrogen is also produced in a form of photosynthesis by cyanobacteria. This process can be used on an industrial scale.
Overall, hydrogen technology, whether it be new developments, such as hydrogen fueled cars, or old, like the Haber process, remains critical to the chemical industry.