Argon (Ar) is a monatomic, chemically inert gas which constitutes slightly less than 1% of the air. Its gaseous specific gravity is 1.38 and its boiling point is -302.6°F (-185.9°C). Argon is colourless, odourless, tasteless, non-corrosive, non-flammable, and non-toxic. Commercial argon is the product of cryogenic air separation, whereby liquefaction and distillation processes are used to produce a low-purity ‘crude’ argon product which is then purified to produce the commercial product. Argon is used primarily for its properties as an inert gas in applications such as arc welding, steel-making, heat treating, and electronics manufacturing.

Carbon dioxide (CO2) is a colourless, odourless, non-flammable and slightly acidic liquefied gas. CO2 is heavier than air and soluble in water. CO2 is produced industrially by using sources of CO2 obtained through processes in the petrochemical industry, or by burning natural gas in cogeneration processes. Air Products supplies CO2 to customers worldwide as a liquefied gas. It is delivered under pressure in steel cylinders and refrigerated in thermally insulated containers.

Hydrogen (H) makes up 98% of the known universe, and it is the third most abundant element on the earth’s surface. It is the lightest of all the gases, with a gaseous specific gravity of 0.0695. It is a component of water, minerals, and acids, and it makes up a fundamental part of all hydrocarbons and organic substances. At atmospheric temperatures and pressures, hydrogen exists as a gas; however, it liquefies at -252.9°C (-423°F). Next to helium, it is the coldest known fluid. Hydrogen (H) is valued for it’s reactive and protective properties. Many industries such as electronics, food, glass, chemicals, refining, and more can benefit from its unique properties to improve quality, optimise performance, and reduce costs. One such application has benefits in the refining industry. It lowers sulfur in fuels and the corresponding sulfur dioxide, enables catalytic converters to remove other pollutants from transportation fuels, helps conserve precious natural resources by enabling refiners to increase the amount of fuel that can be produced from every barrel of crude oil, and enables refiners to use all qualities of crude, regardless of how heavy or sour.

Nitrogen (N2) constitutes 78.03% of the air, has a gaseous specific gravity of 0.967, and a boiling point of -320.5°F (-195.8°C) at atmospheric pressure. It is colourless, odourless, and tasteless. Nitrogen is often used as an ‘inert’ gas due to its non-reactive nature with many materials. However, nitrogen can form certain compounds under the influence of chemicals, catalysts, or high temperature. Commercial nitrogen is produced through a variety of air separation processes, including cryogenic liquefaction and distillation, pressure swing adsorption (PSA), and membrane separation. Gaseous nitrogen is used in the chemical and petroleum industries for storage tank blanketing and vessel inerting applications. It is also used extensively by the electronics and metals industries for its inert properties. Liquid nitrogen, produced by the cryogenic air separation process, finds wide use as a refrigerant in applications such as cryogenic grinding of plastics and food freezing.

Oxygen (O2) constitutes approximately 21% of the air, has a gaseous specific gravity of 1.1, and has a boiling point of -297.3°F (-183°C). Oxygen is produced by air separation processes that use either cryogenic liquefaction and distillation or vacuum swing adsorption (VSA) separation. Oxygen can be stored and shipped as either a gas or a cryogenic liquid. The principal uses of oxygen stem from its strong oxidising and life-sustaining properties. It is used in medicine for therapeutic purposes and in the metals industry for steelmaking and metal-cutting applications. In the chemical and petroleum industries, oxygen is used in the production of a wide variety of fuels and chemicals. In the pulp and paper industry, oxygen is used for a variety of applications, including pulp bleaching, black liquor oxidation, and lime kiln enrichment. In the glass industry, oxygen/fuel combustion is used to reduce particulate and NOx emissions in melting operations. Oxygen is also used for gasification applications for producing synethesis gas to make chemicals, fuels, electricity, hydrogen or steam.