Oxygen is a colorless, odorless gas that comprises 22% of the air and is essential for human life. It is produced commercially via cryogenic distillation that separates oxygen from other air components. Oxygen has numerous industrial uses including in steel production, welding, rocket fuel, and medical applications. Prolonged exposure to high concentrations of oxygen can be toxic to humans. Common materials for oxygen storage and transport include stainless steel and alloys.

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2. INTRODUCTION
 Oxygen is a tasteless gas. Oxygen has no smell or color. It comprises 22
per cent of the air. Oxygen is found in the human body, the Sun, oceans
and the atmosphere. Oxygen is part of the air people use to breathe.
Human exposure to atmospheres containing 12 per cent or less oxygen
will bring about unconsciousness without warning. It is also part of the
stellar life cycle.
 Oxygen is shipped as a non liquefied gas at pressures of 2000 psig (138
bar) or above, also as a cryogenic liquid at pressures and temperatures
below 200 psig (13.8 bar) and -2320F (-146.50C). Oxygen is produced at
air separation plants by liquefaction of atmospheric air and separation
of the oxygen by fractionation. Very small quantities are produced by
the electrolysis of water.
 Oxygen also acts as a ligand for transition metals, forming metal-O2
bonds with the iridium atom in Vaska's complex, with the platinum in
PtF6. Oxygen combines with iron and present at center of the heme
group of hemoglobin

3. HISTORY
 About one-half of the earth's crust is made up of chemical compounds
containing oxygen, and a fifth of our atmosphere is occupied by oxygen gas.
The human body is about two-thirds oxygen. Although oxygen has been
present since the beginning of scientific investigation, it wasn't discovered and
recognized as a separate element until 1774 when Joseph Priestley of England.
Joseph Priestley isolated oxygen by heating mercuric oxide in an inverted test
tube with the focused rays of the sun.
 Oxides are generated when oxygen joins with other elements. It is part of
hydroxides and various acids. Oxygen can be cooled under boiling point. It will
turn light blue. This color is retained even when in a solid state.
 In 1895, Karl Paul Gottfried von Linde of Germany and William Hampson of
England independently developed a process for lowering the temperature of air
until it liquefied. By carefully distillation of the liquid air, the various
component gases could be boiled off one at a time and captured. This process
quickly became the principal source of high quality oxygen, nitrogen, and
argon.

4. HISTORY Cont
 French scientist Antoine Lavoisier, with the basics of Joseph Priestley
experiments, experimented further and determined that it was one of
the two main components of air. Lavoisier coined the term to new gas
as oxygen using the Greek words oxys, meaning sour or acid, and genes,
refers to producing or forming.
 Approximately 100 million tons of O2 is extracted from the air annually
for industrial purposes. The steel industry is the major consumer of
oxygen for its major process. In steel industry the process of smelting
iron ore into steel requires high pressure injection of oxygen into the
molten steel to remove impurities from the steel. In the steelmaking
industry huge quantities of O2 are blown through the impure molten
ore, where it burns off any impurities that are present (particularly
carbon). About 1 tone of O2 is required for every tone of finished steel.


5. Oxygen as Rocket Propellants
 The first use of liquid rocket propellants came in 1923 when Robert
Goddard of the United States developed a rocket engine using gasoline
as the fuel and liquid oxygen as the oxidizer. In 1926, he successfully
flew a small liquid-fueled rocket a distance of 184 ft (56 m) at a speed
of about 60 mph (97 kph).
 After World War II, new technologies brought significant
improvements to the air separation process used to produce oxygen.
Production volumes and purity levels increased while costs decreased.
In 1991, over 470 billion cubic feet (13.4 billion cubic meters) of oxygen
were produced in the United States, making it the second-largestvolume industrial gas in use.
 Worldwide the five largest oxygen-producing areas are Western
Europe, Russia (formerly the USSR), the United States, Eastern Europe,
and Japan.

6. Oxygen Major industrial
applications
 Oxygen is required to produce energy in industrial processes, generators and
ships. It is also used in airplanes and cars. As liquid oxygen, it burns spacecraft
fuel. This produces the thrust needed in space.
 Astronauts’ spacesuits have close to pure oxygen. Oxygen is needed by all living
organisms. Through a process known as aerobic respiration, energy from food
is generated. This allows humans and animals to perform their daily activities.
 Oxygen comprises a fifth of air volume, two-thirds of the human body and 87
per cent water. In its natural form it is all over the atmosphere. Commercial
preparation involves fractional distillation of air and liquefaction and water
electrolysis. Oxygen can be used to make compounds with all elements minus
inert gasses. Oxygen may be dissolved.
 In 1901, compressed oxygen gas was burned with acetylene gas in the first
demonstration of oxy-acetylene welding. This technique became a common
industrial method of welding and cutting metals.

7. Oxygen Raw Materials
 Oxygen can be produced from a number of materials, using several
different methods. The most common natural method is photosynthesis, in which plants use sunlight convert carbon dioxide in the air
into oxygen. This offsets the respiration process, in which animals
convert oxygen in the air back into carbon dioxide.
 The most common commercial method for producing oxygen is the
separation of air using either a cryogenic distillation process or a
vacuum swing adsorption process. Nitrogen and argon are also
produced by separating them from air.
 Oxygen can also be produced as the result of a chemical reaction in
which oxygen is freed from a chemical compound and becomes a gas.
This method is used to generate limited quantities of oxygen for life
support on submarines, aircraft, and spacecraft.

8. Oxygen Raw Materials Cont ..
 Hydrogen and oxygen can be generated by passing an electric current
through water and collecting the two gases as they bubble off.
Hydrogen forms at the negative terminal and oxygen at the positive
terminal. This method is called electrolysis and produces very pure
hydrogen and oxygen. It uses a large amount of electrical energy,
however, and is not economical for large-volume production.
 Most commercial oxygen is produced using a variation of the cryogenic
distillation process originally developed in 1895. This process produces
oxygen that is 99+% pure. More recently, the more energy-efficient
vacuum swing adsorption process has been used for a limited number
of applications that do not require oxygen with more than 90-93 per
cent purity.
 Here are the steps used to produce commercial-grade oxygen from air
using the cryogenic distillation process.

9. Oxygen Toxicity
 This condition takes place when someone breathes excessive pure oxygen. The
gas is essential for living, but only up to a point. Humans can only breathe 21
percent oxygen. The other elements are composed of nitrogen and other
elements. When too much oxygen is inhaled, humans will experience difficulty
breathing. Other symptoms will manifest. These include inflammation of the
airways, nausea and tunnel vision.
 Toxicity can be due to elevated oxygen levels or other causes. High pressure,
short duration exposure can lead to central nervous system damage. Long term
exposure may cause ocular or pulmonary problems. Central nervous system
oxygen toxicity is usually experienced by divers. Those who spend time at high
altitudes are also susceptible. Toxicity can occur when a diver goes in deep
enough. This is because the diver takes in more oxygen than usual.
 Symptoms include twitching, dizziness and nausea. In extreme cases, seizures
or death occur. However, toxicity can take place if oxygen is higher than 21 per
cent in normal atmospheric pressure and at 50 per cent, toxicity will occur.

10. Materials of Construction
 Gaseous oxygen is noncorrosive and may be contained in systems
constructed of any common metal. Stainless steel, bronze and
brass are the preferred material for all metal components coming
in contact with oxygen. At the temperatures of liquid oxygen,
ordinary carbon steels and most alloy steels lose their ductility
and are therefore considered unsatisfactory for liquid oxygen
service. Carbon Steel cannot be adequately cleaned for oxygen
service.
 In healthcare institutions like hospitals, oxygen supplies are kept
in stock. These are provided to patients who have difficulty
breathing. This breathing apparatus is also used by astronauts
walking in space, scuba divers and mountaineers. Oxygen gas is
used to destroy bacteria. The same oxygen gas is used to treat
victims of carbon monoxide poisoning.

11. Materials of Construction Cont ..
 Oxygen gas is used in water treatment and chemical combustion.
Scientific researchers use the oxygen-18 and oxygen-16 isotopes
in fossils to determine Earth’s climate millennia ago. This gas is
also used in polyester polymers and antifreeze production. These
polymers are used to create fabrics and plastics. You will also find
oxygen tanks in aircraft and submerge vessels.
 Oxygen is essential for life and it takes part in processes of
combustion, its biological functions in respiration make it
important.
 Oxygen is sparingly soluble in water, but the small quantity of
dissolved oxygen in is essential to the life of fish.

12. Oxygen Uses
 The uses of oxygen are varied. Oxygen is used in puland paper
manufacturing, ceramic creation, glass making and petroleum
processing. It is also part of pharmaceuticals, metal refining and
other elements.
 Oxygen is used extensively in medicine, high altitude flying,
deep-sea diving and a power source in the space programs.
Industrial applications include utilization with acetylene,
propane, hydrogen and other fuel gases for such purposes as
metal cutting, welding, hardening and scarfing.
 One of its major uses is in production of synthesis gas which is
used to make gasoline, methanol and ammonia. It is also used in
production of nitric acid, ethylene and other compounds.

13. Oxygen Uses Cont ..
 Oxygen gas is used with hydrogen or coal gas in blowpipes and
with acetylene in the oxy-acetylene torch for welding and cutting
metals.
 Oxygen gas is also used in a number of industrial processes.
 Medicinally, oxygen gas is used in the treatment of pneumonia
and gas poisoning, and it is used as an anesthetic when mixed
with nitrous oxide, ether vapour, etc.
 Carbon Dioxide is often mixed with the oxygen as this stimulates
breathing, and this mixture is also used in cases of poisoning and
collapse for restoring respiration

14. Oxygen Uses Cont ..
 Liquid oxygen mixed with powdered charcoal has been
used as an explosive.
 Oxygen is important for all combustion process, such as
the burning of the hydrocarbon fuels such as oil, coal,
petrol, natural gas which heat our homes and power our
cars.
 Fires need O2 to burn, and removal of O2, by for example
smothering or spraying with CO2, is one way to extinguish
fires.
 Welding, using oxy-acetylene torches is another important
industrial application, whereby acetylene gas (the fuel) and
oxygen are mixed in the correct proportions and ignited to
provide an intensely hot flame.

15. References
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