In many processes, the oxygen for reaction can be obtained from the use of air. In the chemical and petroleum industries, oxygen is used as a feed component to react with hydrocarbon building blocks to produce chemicals such as alcohols and aldehydes.
LIQUID OXYGEN SYSTEM PLUS
Benefits such as fuel and energy savings plus lower total emission volumes are often achieved when air is enriched or replaced with higher-purity oxygen. Steel and iron manufacturers also extensively use oxygen or oxygen-enriched air to affect chemical refining and heating associated with carbon removal and other oxidation reactions. Oxygen is widely applied in the metal industries in conjunction with acetylene and other fuel gases for metal cutting, welding, scarfing, hardening, cleaning and melting. Liquid oxygen is used as an oxidant for liquid fuels in the propellant systems of missiles and rockets. Oxygen is commonly relied upon in health and medical applications. The primary uses of oxygen relate to its strong oxidizing and life-sustaining properties. However, most applications use oxygen after it is vaporized to the gaseous form.
Oxygen is generally liquefied so that it can be more effectively transported and stored in large volumes. The liquid oxygen is sent to a cryogenic storage tank. This crude oxygen liquid is withdrawn from the column and sent to a low-pressure column, where it is distilled until it meets commercial specifications. Next, the air enters a high pressure distillation column where it is physically separated into a vaporous form of nitrogen at the top of the column and a liquid form of “crude” oxygen (~90% O2) at the bottom. The air then passes through heat exchangers where it is cooled to cryogenic temperature. Air is compressed and sent through a cleanup system where moisture, carbon dioxide, and hydrocarbons are removed. The ASU manufacturing process begins with a main air compressor and ends at the output of the product storage tanks. Oxygen can also be produced noncryogenically using selective adsorption processes to produce gaseous product. The oxygen is then removed and stored as a cryogenic liquid.
Oxygen is produced by an air separation unit (ASU) through liquefaction of atmospheric air and separation of the oxygen by continuous cryogenic distillation. Piping design should follow similar design and conform to national standards and codes. Vessels used in liquid oxygen service should be designed for the pressure and temperatures involved. A pressure control manifold then controls the gas pressure that is fed to the process or application. Vaporizers convert the liquid oxygen into a gaseous state. This space keeps heat away from the liquid oxygen held in the inner vessel. Between the vessels is an annular space that contains an insulating medium from which all the air has been removed. There is an inner vessel surrounded by an outer vessel. The cryogenic tank is constructed, in principle, like a vacuum bottle. A typical storage system consists of a cryogenic storage tank, one or more vaporizers and a pressure control system. Liquid storage is less bulky and less costly than the equivalent capacity of high-pressure gaseous storage. Oxygen is often stored as a liquid, although it is used primarily as a gas. The product also requires special equipment for handling and storage. Liquid oxygen has a boiling point of –297☏ (–183☌).īecause the temperature difference between the product and the surrounding environment is substantial-even in the winter-keeping liquid oxygen insulated from the surrounding heat is essential. Cryogenic liquids are liquefied gases that have a normal boiling point below –130☏ (–90☌). Vessels should be manufactured to American Society of Mechanical Engineers (ASME) codes and designed to withstand the process temperatures and pressures. Equipment used in oxygen service must meet stringent cleaning requirements, and systems must be constructed of materials that have high ignition temperatures and that are nonreactive with oxygen under the service conditions. Materials that burn in air will burn more vigorously in oxygen. Oxygen will react with nearly all organic materials and metals, usually forming an oxide. Although nonflammable, oxygen is a strong oxidizer. Liquid oxygen is pale blue and extremely cold. Oxygen is the second largest component of the atmosphere, comprising 20.8% by volume. Temperature Control for Food Mixing and Forming.Printed Circuit Board Assembly and Test.Integrated Circuit Packaging, Assembly & Test.Fracturing for Unconventional Oil & Gas.
0 kommentar(er)
