Oxygen
plants are cost effective and safe oxygen producing system that range from
small portable units to large sized gas plants. The main purpose of oxygen
plants is to produce industrial and medical oxygen up to 99.9% purity. The
oxygen gas plants are used to serving markets for bottling cylinders,
brazing of metals, industrial gas cutting of steel, production of steel
glass and ampule industry, used in petrochemical industry, oil & gas
industry, animal husbandry and used for fabrication.
The oxygen plant units commonly operate according to cryogenic technology
which is the preferred technique for large sized plants or through non
cryogenic technology-PSA/VPSA/VSA (Pressure swing adsorption/Vacuum pressure
swing adsorption/Vacuum swing adsorption), preferable for small and medium
sized plants. However, it is basically the specifics of the application
which decide which technology will be most economical. The oxygen plant can
also be used to produce nitrogen and argon from the air at the same time.
These oxygen plants can be designed as per their application requirements or
as per the specifications of customers.
Manufacturing Process (Cryogenic Process)
The process of producing oxygen in oxygen gas plants involves the following
steps:
Step 1: Compression of atmospheric air
In the first stage of the production process, the free saturated air is
sucked from atmosphere with the help of a highly efficient dry-type suction
filter or an air compressor.
Step 2: Purification of air
The next step involves the cleaning of air by removing moisture, oil
traces, carbondioxide and other impure products in the process air. In the
cryogenic technology, the compressed air is chilled in a chilling unit and
transfered to a moisture separator where the condensed moisture gets
separated before entering into Molecular Sieve Battery. Before that the air
is passed through an oil absorber to remove oil.
Step 3: Cooling of air
The process air before liquefication in the gas plant is cooled to
below-zero temperature (cryogenic). After pre cooling, the main portion of
the process air enters the expansion engine through the heat exchanger . The
temperature of the air further drops down, somewhere about -165 deg C by the
expander. Rest of air enters into a highly efficient expansion engine, where
the air is cooled further down to (-150) deg C before entering into bottom
column. The liquefied air collected at the bottom column from both these
streams is known as "rich liquid".
Step 4: Separation of air
After the colling, the air enters the air separation unit where the air is
converted into liquid air by deep cooling at low or cryogenic temperatures
and is separated into liquid oxygen and nitrogen.
Step 5: Filling of oxygen
The final stage in the process is the transport of liquid oxygen from the
condenser to the cryogenic liquid oxygen pump for filling gas cylinders.
Manufacturing process (PSA process)
PSA technology is another technique used in producing oxygen but it is
preferred for small sized or portable plants. The technique is based on the
selective adsorption process of gas molecules under pressure on the surface
of highly porous and efficient adsorbent, usually zeolite based molecular
sieve. In PSA System, when compressed air is passed through zeolite based
molecular sieve, the molecules of oxygen, moisture & other impure gases
are adsorbed on the surface and oxygen which is not adsorbed comes out.
Equipment Required in Oxygen Plants
- Molecular Battery
- Purger
- Pressure Skid
- Expander
- Chilling Unit
- Oil Adsorber
- Gas Compressor
Types of Oxygen Plants
Depending on the manufacturing process, oxygen plants can be classified as
follows:
- Adsorption Oxygen Plants: High-performance gas plants
developed for oxygen production from atmospheric air and cylinder
filling.
- Membrane Oxygen Plants: Fully automated membrane gas plants
specially developed for air oxygenation.
- Cryogenic Oxygen Plants: Gas plants for deep air freezing
specially designed to produce both liquid and gaseous oxygen from air.
- Mobile Oxygen Stations: These are transportable gas stations
used to deploy a complete oxygen production cycle with the cylinder
filling option.
Application of Oxygen Plant
The basic property of oxygen is that it makes combustion possible, and it
is this property which makes it highly usable in various industrial
applications. Being the largest volume industrial gas, oxygen plants are
used in the following industries :
- Petroleum Recovery and Refining
- Chemical Industry
- Steel Manufacturing Industry
- Pulp and Paper Industry
- Glass Manufacturing
- Fabrication industry
- Medical industry
Buyer's Guide
Technical specifications to consider for purchasing oxygen gas plants are:
- Size: Large, Medium, Small, Portable
- Capacity: Oxygen Pressure (upto)
- Purity
- Power Connected
- Power Consumed
- Power Supply
- Air Capacity
|
- Working Pressure
- Starting Time (After Defrost)
- Starting Time (After Tripping)
- Areas Required
- Assembly Height
- Weight
- Air Separation Column
|
Oxygen
Plant
