Is it possible to use ionized gas as fuel? Have you ever wondered what makes those neon signs glow? Or what makes the auroras so spectacular? You guessed it – it’s ionized gas. When a gas is ionized, it visually manifests as bright light, as seen in fluorescent lamps, neon lights, and even outer space. This ionized state of a gas is called plasma, which is the fourth state of matter (after solids, liquids and gases). Ionized gas as fuel is more common than you might expect.
Did you know? Plasma fills most of outer space – including the sun, solar wind, the space between planets and galaxies, and the space between virtually all other celestial bodies in the universe!
What is ionization or ionized gas?
When sufficient energy is provided to a gas, the atoms or molecules in the gas either trap electrons or lose electrons, thus forming ions. They are said to acquire a negative charge when they gain electrons and a positive charge when they lose electrons.
When a significant portion of a given amount of gas is ionized, it is referred to as plasma. The electrical characteristics of the gas change dramatically when ionized.
How is ionized gas produced?
Gases are usually ionized by one of two methods – electron ionization, in which a beam of electrons is passed through the gas to be ionized, or chemical ionization, in which a ‘reagent’ gas is introduced into the gas to be ionized. Other methods include field desorption, particle bombardment, laser desorption, and atmospheric pressure ionization. Either way, ionized gas as fuel has many applications.
Ionized gas as Fuel
Ionized gases find a wide variety of industrial and engineering applications. Let’s examine a few examples of ionized gas as fuel in one form or another:
Plasma torch: A plasma torch is a device for generating a jet of plasma.
Plasma Arc Cutting: Plasma torches are a main component in plasma cutters that are used to cut materials like stainless steel, aluminium, copper and other electrical conductors. These plasma cutters are employed in fabrication, industrial construction, scrapping, and in the automotive industry (for repairs and restorations). With ionized gas as fuel. plasma cutters offer high speed and precision and are a low-cost option for large industries as well as small hobby shops.
Plasma spraying: This is a type of coating process in which molten material like metals or alloys are coated onto a surface. Plasma torches propel the molten material towards a substrate, thus forming a uniform deposit or coating on its surface. Plasma spraying is typically adopted to coat structural materials, in order to protect them from extreme temperatures, corrosion, and wear.
Plasma arc welding: Plasma torches are also utilised in arc welding processes. Plasma is forced through a copper nozzle, which constricts the arc and propels the plasma to exit at a high velocity, with temperatures reaching up to 28,000 degrees Celsius.
Plasma gasification
Waste treatment: Plasma torches are employed in the conversion of organic matter from wastes, into syngas (synthetic gas), which primarily constitutes hydrogen and carbon monoxide. Waste is melted and vaporized, and the resulting syngas is used to generate electricity.
Internal combustion engines: The syngas obtained from plasma gasification is easily combustible and is therefore, used as fuel for internal combustion engines.
Electricity generation
Ionized gases are used in magnetohydrodynamic (MHD) generators to produce electricity. Ionized gases are made to pass through a magnetic field, thereby generating an electric current. These systems are said to be approximately 25% more efficient than nuclear power plants, in electricity generation.
Air ionisers as air purifiers
Did you know that air can be ionized? An air ionizer uses high voltage to ionize air molecules, which then become positively or negatively charged. These charged ions attach themselves to particulate matter in the air and are collected by the ionizer, thus ‘purifying’ the air. These air purifiers are utilized in the removal of asthma-inducing particles and other allergens from the air. However, they are also said to produce ozone gas, because of which they are not very popular.
Plasma sterilization
This is a new technique that is emerging, which uses ionized gas to kill microbes that are resistant to other cleaning methods. It is mostly being researched for use in space exploration, specifically for sterilizing spacecraft, so as not to ‘contaminate’ other moons and planets.
Summary
The fact that ionized gas is not just another ‘gas’ like oxygen or hydrogen, but the fourth state of matter, shows its significance and importance in our universe. Emerging technologies that make use of ionization, are typically low-cost and more efficient than conventional systems, whether they are used in electricity generation, spacecraft sterilization, or industrial applications. As researchers gradually discover more uses for ionization, and consequently, ionized gases, and opportunities for ionized gas as fuel, it is apparent that they will continue to be of tremendous value, especially to the scientific and engineering community in the years to come.
