Various industries use oxygen gas for manufacturing. In steel and other metal production, the gas is used to increase the efficiency of furnaces and replace coal as its main source of heat. It also increases the temperatures of flames in welding torches for the purpose of welding or cutting metal. Oxygen is used by the paper industry to reduce pollution when processing their materials and making their products. The gas also helps the glass industry by boosting combustion in glass furnaces and reducing pollution to meet government standards.
The medical industry uses concentrated oxygen gas. It is delivered to hospitals in liquid form, and distributed for use during emergencies or to ease the suffering of patients. Oxygen is also used in the home. Portable units are used to treat a plethora of health issues. Also, some small or remotely located hospitals rely on portable oxygen, because large-scale oxygen delivery may not be possible.
Oxygen is also used for environmental purposes. It is often inserted into sewage in order to reduce the amount of hydrogen sulfide. This reduction in sulfur also reduces odor and corrosion. Additionally, it is applied as a substitute for chlorine in treating drinking water. Underwater equipment, such as breathing tanks, are filled with oxygen. Fish farms use oxygen to maintain a steady supply and support the fish being raised in a pond or tank. Rockets use oxygen as part of a chemical reaction with hydrogen and methane in their fuel.
In order to harness oxygen, industries must extract it using a process called cryogenic air separation. First, the air is compressed and cooled, removing any traces of water. The air is then brought to room temperature through water- or air-cooled devices. Carbon dioxide and water vapor is filtered out. Next, the air is brought down to cryogenic temperature, which is minus-300 degrees Fahrenheit. Using an air separation machine, the air is separates nitrogen and oxygen from each other. Finally, the liquid nitrogen and oxygen are placed in storage tanks.