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
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.
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-largest-volume 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.
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.
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.
Raw Materials
Oxygen can be produced from a number of materials, using several different methods. The most common natural method is photo-synthesis, 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.
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.
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.
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.
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.
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.
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.
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.
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