Oxygen plants are industrial systems designed to generate oxygen. They typically use air as a
feedstock
A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished goods, energy, or intermediate materials that are feedstock for future finished products. As feedst ...
and separate it from other components of air using
pressure swing absorption or
membrane separation
Membrane technology encompasses the scientific processes used in the construction and application of membranes. Membranes are used to facilitate the transport or rejection of substances between mediums, and the mechanical separation of gas and li ...
techniques. Such plants are distinct from cryogenic separation plants which separate and capture all the components of air.
Application
Oxygen finds broad application in various technological processes and in almost all industry branches. The primary oxygen application is associated with its capability of sustaining burning process, and the powerful oxidant properties.
Due to that, oxygen has become widely used in the metal processing, welding, cutting and brazing processes. In the chemical and petrochemical industries, as well as in the oil and gas sector oxygen is used in commercial volumes as an oxidizer in
chemical reaction
A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the pos ...
s.
*Metal
gas welding
Principle of burn cutting
Oxy-fuel welding (commonly called oxyacetylene welding, oxy welding, or gas welding in the United States) and oxy-fuel cutting are processes that use fuel gases (or liquid fuels such as gasoline or petrol, diesel, ...
, cutting and brazing - The use of oxygen in gas-flame operations, such as metal welding, cutting and brazing is one of the most significant and common applications of this gas. Oxygen allows generating high-temperature flame in welding torches thus ensuring high quality and speed of work performance.
*Metal industry - Oxygen is heavily used in the metal industry where it helps to increase burning temperature by the production of
ferrous and non-ferrous metals
In metallurgy, non-ferrous metals are metals or alloys that do not contain iron (allotropes of iron, Ferrite (iron), ferrite, and so on) in appreciable amounts.
Generally more costly than ferrous metals, non-ferrous metals are used because of d ...
and significantly improve the overall process efficiency.
*Chemical and petrochemical industries - In the chemical and petrochemical industries, oxygen is widely used for oxidation of raw chemicals for recovery of
nitric acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitri ...
,
ethylene oxide
Ethylene oxide is an organic compound with the chemical formula, formula . It is a cyclic ether and the simplest epoxide: a three-membered Ring (chemistry), ring consisting of one oxygen atom and two carbon atoms. Ethylene oxide is a colorless a ...
,
propylene oxide
Propylene oxide is an acutely toxic and carcinogenic organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid with an odour similar to ether, is produced on a large scale industrially. Its major application is its us ...
,
vinyl chloride
Vinyl chloride is an organochloride with the formula H2C=CHCl. It is also called vinyl chloride monomer (VCM) or chloroethene. This colorless compound is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride (PVC ...
and other important
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
s.
*Oil and gas industry - In the oil and gas industry, oxygen finds application as a means for viscosity improvement and enhancement of oil-and-gas
flow properties. Oxygen is also used for boosting production capacity of oil cracking plants, efficiency of high-octane components processing, as well as for the reduction of sulfuric deposits in refineries.
*Fish farming - The use of oxygen in the
fish farming
upright=1.3, Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye">mariculture.html" ;"title="Salmon farming in the sea (mariculture">Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye, Scotland
Fish farming or ...
helps increase the survival and fertility ratios and reduce the
incubation period
Incubation period (also known as the latent period or latency period) is the time elapsed between exposure to a pathogenic organism, a chemical, or radiation, and when symptoms and signs are first apparent. In a typical infectious disease, the i ...
. Along with fish culture, oxygen is applied for shrimps, crabs and mussels rearing.
*Glass manufacture - In glass furnaces oxygen is effectively used for burning temperature increase and burning processes improvement.
*Waste management - The use of oxygen in incinerators allows significantly increased flame temperatures and eventually ensures enhanced
cost efficiency
Cost efficiency (or cost optimality), in the context of parallel computer algorithms, refers to a measure of how effectively parallel computing can be used to solve a particular problem. A parallel algorithm is considered cost efficient if its asy ...
and incinerator production capacity.
*Medicine - Medical
oxygen therapy
Oxygen therapy, also known as supplemental oxygen, is the use of oxygen as medical treatment. Acute indications for therapy include hypoxemia (low blood oxygen levels), carbon monoxide toxicity and cluster headache. It may also be prophylactica ...
may be administered to patients for various reasons such as low oxygen saturation or to ease respiratory distress.
Adsorption technology
Adsorption principle
Gas separation by adsorption systems is based on differential rates of adsorption of the components of a gas mixture into a solid adsorbent.
Temperature and pressure influence
The current means of gaseous oxygen production from air by the use of adsorption technology produce a high fraction of oxygen as their output. The mechanism of operation of a modern oxygen adsorption plant is based on the variation of uptake of a particular gas component by the adsorbent as the temperature and
partial pressure
In a mixture of gases, each constituent gas has a partial pressure which is the notional pressure of that constituent gas as if it alone occupied the entire volume of the original mixture at the same temperature. The total pressure of an ideal gas ...
of the gas is changed.
The gas adsorption and adsorbent regeneration processes may therefore be regulated by varying of the pressure and temperature parameters.
Pressure swing adsorption
The oxygen plant flow process is arranged in such a way that highly absorbable gas mixture components are taken in by adsorbent, while low absorbable and non-absorbable components go through the plant. Today, there exist three methods of arranging the adsorption-based air
separation process
A separation process is a method that converts a mixture or a solution (chemistry), solution of chemical substances into two or more distinct product mixtures, a scientific process of separating two or more substance in order to obtain purity. At ...
with the use of swing technologies: pressure (PSA), vacuum (VSA) and mixed (VPSA) ones. In the pressure swing adsorption flow processes, oxygen is recovered under above-atmospheric pressure and regeneration is achieved under
atmospheric pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 7 ...
. In vacuum swing adsorption flow processes, oxygen is recovered under atmospheric pressure, and regeneration is achieved under
negative pressure
Negative pressure may refer to:
* Negative value of a pressure variable
* Negative room pressure, a ventilation technique used to avoid contaminating outside areas
* Negative pressure ventilator, also known as an iron lung
* Negative-pressure wou ...
. The mixed systems operation combines pressure variations from positive to negative.
Adsorption oxygen plants
The adsorption oxygen plants produce 5 to 5,000
normal cubic meters per hour of oxygen with a purity of 93-95%. These systems, designated for indoor operation, are set to effectively produce gaseous oxygen from atmospheric air.
An unquestionable advantage of adsorption-based oxygen plants is the low cost of oxygen produced in the cases where there are no rigid requirements to the product oxygen purity.
Structurally, the adsorption oxygen plant consists of several adsorbers, the compressor unit, pre-purifier unit, valve system and the plant
control system
A control system manages, commands, directs, or regulates the behavior of other devices or systems using control loops. It can range from a single home heating controller using a thermostat controlling a domestic boiler to large industrial c ...
.
A simple adsorber is a column filled with layers of specially selected adsorbents – granular substances preferentially adsorbing highly adsorbable components of a gas mixture.
Where gaseous oxygen purity is required at the level of 90-95% with the capacity of up to 5,000 Nm
3 per hour, adsorption oxygen plants are the optimal choice. This oxygen purity may also be obtained through the use of systems based on the cryogenic technology; however, cryogenic plants are more cumbersome and complex in operation.
Membrane technology
Innovation technology available today
Some companies produce high-efficiency systems for oxygen production from atmospheric air with the help of
membrane technology
Membrane technology encompasses the scientific processes used in the construction and application of membranes. Membranes are used to facilitate the transport or rejection of substances between mediums, and the mechanical separation of gas and li ...
.
Membrane operation principle
The basis of gas media separation with the use of membrane systems is the difference in velocity with which various gas mixture components permeate membrane substance. The driving force behind the gas separation process is the difference in partial pressures on different membrane sides.
Membrane cartridge
A modern gas separation membrane used by GRASYS is no longer a flat plate, but is formed by hollow fibers. Membrane consists of a porous polymer fiber with the
gas separation
Gas separation can refer to any of a number of techniques used to separate gases, either to give multiple products or to purify a single product.
Swing adsorption techniques
Pressure swing adsorption
Pressure swing adsorption (PSA) pressurizes ...
layer applied to its external surface. Structurally, a hollow fiber
membrane
A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. B ...
is configured as a cylindrical cartridge representing a spool with specifically reeled polymer fiber.
Compressor and vacuum technologies
Due to the membrane material high permeability for oxygen in contrast to nitrogen, the design of membrane oxygen complexes requires a special approach. Basically, there are two membrane-based oxygen production technologies: compressor and vacuum ones.
In the case of compressor technology, air is supplied into the fiber space under excess pressure, oxygen exits the membrane under slight excess pressure, and where necessary, is pressurized by booster compressor to the required
pressure level. By the use of
vacuum technology
A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or "Void (astronomy), void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Ph ...
, a vacuum pump is used for the achievement of partial pressures difference.
Membrane oxygen plants
Designed for indoor operation, membrane oxygen plants allow efficient air enrichment with oxygen up to the concentration of 30-45%. The complexes are rated to 5 to 5,000 nm3/hr of oxygenated air.
In the membrane oxygen plant, gas separation is achieved in the gas separation module composed of hollow-fiber membranes and representing the plant critical and
high-technology
High technology (high tech), also known as advanced technology (advanced tech) or exotechnology, is technology that is at the cutting edge: the highest form of technology available. It can be defined as either the most complex or the newest te ...
unit. Apart from the gas separation unit, other important technical components are the booster compressor or vacuum pump, pre-purifier unit, and the plant control system.
The adoption of membrane systems for air enrichment purposes promises multiple oxygen savings where the oxygen concentration of 30-45% is sufficient to cover process needs. In addition to customer saving on the product oxygen cost, there is a collateral economic effect based on extremely low operating costs.
With the incorporation of the membrane technology, oxygen plants have outstanding technical characteristics. Membrane oxygen plants are highly reliable due to the absence of
moving parts
Machines include both fixed and moving parts. The moving parts have controlled and constrained motions.
Moving parts are machine components excluding any moving fluids, such as fuel, coolant or hydraulic fluid. Moving parts also do not include ...
in the gas separation module.
The systems are very simple in operation – control of all operating parameters is carried out automatically. Because of the plant's high automation degree, staffed oversight is not required during its operation.
Membrane oxygen plants are finding increasingly broad application in various industries all over the world. With moderate requirements to oxygen purity in product - up to 30-45%, membrane systems generally prove more economically sound than adsorption and cryogenic systems. In addition, membrane plants are much simpler in operation and more reliable.
Advantages of adsorption and membrane oxygen plants
*Complete automation and simplicity of operation;
*Staffed oversight is not required during operation;
*Enhanced failure safety and reliability;
*Quick start and stop;
*Moderate dimensions and light weight;
*Low
noise level;
*Extended operational life;
*Low operating costs;
*No special workshop requirements;
*Easy installation and integration into an existing air system.
Disadvantages
* Relativity low oxygen purity - 93-95% for adsorption and 30-45% for membrane plants;
* Limited capacity.
* High power consumption.
References
{{DEFAULTSORT:Oxygen Plant
oxygen plant Oxygen
Industrial gases
Gas technologies