What does the air that keeps us alive, that we need for breathing and photosynthesis, do?
Air is a mixture of many different gases, and each gas has its properties. The composition of the air is not constant. It can vary from time to time and from place to place.
The composition of the atmosphere
The atmosphere consists of 79% nitrogen (N2), 20% oxygen (O2), and 1% other gases (argon (Ar), and carbon dioxide (CO2)). Nitrogen and oxygen together make up 99% of the planet’s atmosphere.
Other gases are smaller components, but sometimes they are very important.
Of these gases, argon, oxygen, and nitrogen are primarily produced by separating air into its constituent components. This normally happens by lowering the air temperature until each component is liquid and then can be removed.
Carbon dioxide is produced as a by-product of several chemical processes.
Oxygen (O2) is a gas that is vital for every organism. It is odorless, colorless, and tasteless. It is delivered in steel bottles and batteries, which must not come into contact with grease, otherwise, they would react with flame. Liquid oxygen is characterized by light blue color. It is delivered in blue or white steel bottles weighing 8.5 kg, which may not come into contact with grease, because they would react with flame. They are transported in special carts or pallets. All elements, except inert gas, react with oxygen at different temperatures will form oxides.
Oxygen is used in many areas, it serves as a vital gas not only in medicine (in hospital and clinical care for resuscitation, and surgery, and various therapies), but it is also irreplaceable in the industry:
– Metal processing – Oxygen creates an extremely high-temperature flame for cutting and welding various metals.
– Chemical industry – As an extremely active gas, oxygen is used to create various chemical compounds, such as nitric acid, propylene oxide, ethylene oxide, etc. In waste incinerators, oxygen increases combustion efficiency.
– Glass production – Oxygen increases the efficiency of the combustion process when melting glass.
– Wood and paper industry
– Aviation – Oxygen is used in aircraft to charge the respiratory system, as well as in remote oxygen supply systems. Liquid oxygen is widely used in mixtures with liquid hydrogen or paraffin as a rocket fuel oxidizer.
– Food industry – oxygen is usually used for packaging: fruits and vegetables (oxygen allows the product to breathe and keep its freshness) and red meat (to maintain the color of the meat). It is also used in the preparation of drinking water and as an inert gas to eliminate oxidation and extend the shelf life of the product. When it comes to security, it is important to note that the instructions for use are a great benefit because increasing the oxygen concentration by only a few percent above the average causes a risk of fire.
Argon (Ar) is a non-toxic inert gas of high density, odorless, and colorless which is used as a shielding gas in welding various metals. When argon is used during the welding process, the molten metal is denser, and as a result, the metals are welded faster. Argon is characterized by extremely low thermal conductivity and therefore is also used in other areas of industry.
Argon is obtained commercially by the distillation of liquid air, and its application is wide, especially in the industry:
– Metal processing – Argon protects materials from oxidation during welding, melting, cutting of metals and their alloys: alloys of aluminum, magnesium, nickel, steel. Argon is also used as a shielding gas when welding ordinary steel and aluminum.
– Glass production – For greater efficiency of thermal and sound insulation. Double and triple pane glass packages are filled with argon.
– Metallurgy – Argon is used for metal purification and the protection of liquid metal from contact with the environment and their interactions.
– Electronics – Pure argon is used as an inert gas that protects semiconductors from impurities (e.g. argon creates an environment for the growth of silicon and germanium crystals).
– Vehicles and transport – Compressed argon is used to inflate the airbags in vehicles.
-Production of light bulbs – Argon is used to fill incandescent, neon lamps of advertising signs (argon has the attribute to glow blue).
In terms of safety, argon does not cause direct damage to the human body. However, this gas has the characteristic of pushing oxygen out of the air. If the concentration of this gas exceeds 33%, there is a risk of suffocation hazard, so the production area should be ventilated.
Carbon dioxide (CO2) is a colorless, odorless, and tasteless gas, and it’s widespread in nature. Carbon dioxide occurs in three states – gas, liquid and solid. At low temperatures (-78.5 oC), carbon dioxide changes from a solid to a gas form or from a gas to a solid form (which is also called dry ice) passing through the medium liquid form. Carbon dioxide gets in a liquid state only under a pressure of 6 atmospheric pressures (in bottles, carbon dioxide is pressed with 65-70 atmospheric pressures).
Carbon dioxide is used in many fields:
– Industries – Metal processing (Carbon dioxide is used for melting metals and their alloys, alloys of aluminum, magnesium, nickel, steel, etc…
– Fire extinguishers – Carbon dioxide is charged into fire extinguishers – is an effective fire extinguisher, because carbon dioxide does not pollute the environment and cools hot materials.
– Neutralization of alkaline wastewater – alkaline wastewater generated in various areas of industrial production should be neutralized. Carbon dioxide is a more economical and environmentally friendly alternative than ordinary mineral acids.
– Cooling – Carbon dioxide can be used as a natural refrigerant in cooling systems.
– Food industry – Carbon dioxide has many well-known applications in food and beverage industry –
from carbonated beverages and wine preservation to food packaging in a protective atmosphere.
– As dry ice, in solid-state – It is used in food, for storage, cooling of food and beverages in catering,
freezing, as well as for cooling during transport.
Dry ice is also used for cleaning (dry ice blasting – sandblasting of all surfaces without damage with dry ice), in the entertainment industry (stage effects, champagne pyramids), medicine (transport of blood, blood plasma, organs, and vaccines), wineries, industry (degreasing).
Carbon dioxide safety alarm: Unprotected skin contact with carbon dioxide can cause burns.
Production sites should be ventilated.
Helium (He) is a gas without color, odor and taste, it does not react and it’s a particularly light inert gas. The evaporation and boiling point of helium is the lowest of all elements, so liquid helium is an ideal refrigerant where particularly low temperatures are necessary.
This gas is commonly known as party balloon fill that rises to the sky, however, helium is also important in metal processing, chemistry, and pharmacy. It is used in gas mixtures of underwater diving equipment.
Most of the helium molecules are present in the atmosphere, however, their concentration is only about 5 parts of million. Unfortunately, helium resources, as well as other non-renewable natural resources, are decreasing.
Helium is used in many fields:
– Metal processing – Helium is used as a substrate that prevents oxidation during welding of various metals (steel, aluminum, copper, magnesium).
– Balloons – They are known to be able to fly in the sky. Whether you are organizing a wedding, a business celebration, or a private party, they are always an integral part of every celebration.
– Electronics – In order to protect semiconductors and soldering processes from impurities and oxidation, helium is used in the production of electronic parts.
– Other fields of use – Mixtures of helium and oxygen are used in underwater diving equipment and submarines. Helium gas suppresses oxygen, thus facilitating breathing. Gas is used to detect cracks and holes in high-pressure and vacuum systems. Helium is also used in the production of fiber optic telecommunication cables.
Safety: If helium suppresses the oxygen necessary for breathing from the air, it causes suffocation. Liquid helium can cause burns.
Nitrogen (N2) is a colorless, odorless, tasteless, non-toxic, and chemically inert gas (it does not react at low temperatures).
In many industrial areas, nitrogen is considered useful and is used to reduce combustion processes and create a protective environment to avoid oxidation processes. Nitrogen was obtained from atmospheric air by the method of deep freezing.
Nitrogen is used in many fields:
– Chemical industry – Nitrogen is used as a shielding gas to protect raw materials, it is used in the production of ammonia and the production of urea – powdered fertilizer with a high nitrogen content
– from ammonia. Compressed nitrogen gas is non-conductive, so it is used in high-voltage equipment and to ensure the hermetic integrity of the pipe.
– Metal processing – Nitrogen is used for heat treatment of various metals because it creates an inert medium that prevents the oxidation process.
– Electronics – To protect semiconductors and soldering processes from impurities and oxidation, nitrogen is used in the manufacture of electronic parts, (transistors, diodes, integrated circuits).
– Transport and aerospace – To increase the longevity, reduce the probability of explosion and increase pressure stability, nitrogen is used as an alternative to air in vehicle tires due to its property of not maintaining moisture and oxidation. Nitrogen is suitable for fuel systems in military aviation (to reduce the risk of combustion).
– Food industry – Used for food packaging in a modified atmosphere (MAP). In liquid form, it is a means of shock-freezing food, storing biological material, performing cryosurgery, and cryogenic grinding of plastics and rubber.
Safety: If nitrogen suppresses the oxygen necessary for breathing from the air, it causes suffocation. Liquid nitrogen can cause burns.