What Is an Air Separation Plant?

Air separation equipment is the equipment that uses air as the raw material and deep-freezes the compression cycle to turn the air into a liquid state, and then through rectification to gradually separate and produce inert gases such as oxygen, nitrogen, and argon from the liquid air.

Air separation equipment

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Air separation equipment uses air as a raw material and passes the compression cycle

Air separation equipment

At present, there are many types and types of air separation equipment produced in China. There are devices that produce gaseous oxygen and nitrogen, as well as devices that produce liquid oxygen and nitrogen. But in terms of basic processes, there are four main types, namely high pressure, medium pressure, high and low pressure, and full low pressure processes.

The production scale of air separation equipment in China has been able to produce only 20m3 / h (oxygen).

In the equipment that uses the principle of low-temperature distillation to make oxygen, in order to ensure the normal progress of rectification and separation of air in the low-temperature region, the air must be pre-treated in the normal temperature region by filtering, pre-cooling and purification.

The air contains a large amount of dust. During long-term high-speed operation of the air turbine compressor (air compressor for short), dust will cause wear, corrosion and fouling of the impellers, blades and other parts inside the machine, shortening the service life of the machine. Therefore, a raw air filter must be provided to remove dust from the air.

The temperature of the air compressed by the air turbine compressor rises to more than 80 degrees, resulting in subsequent adsorption and heat exchange cannot be performed normally. An air pre-cooling system can be set to effectively reduce the air temperature entering the air separation equipment.

In addition to a large amount of dust in the raw air, there are also hydrocarbons such as moisture, carbon dioxide, and acetylene. Most modern air separation equipment uses molecular sieve purification systems to remove these impurities to improve the cleanliness of the air entering the cold box and prevent moisture. And carbon dioxide concentration threatens the normal operation of air separation equipment. Therefore, gas filtration, pre-cooling and purification equipment is an integral part of air separation equipment.

Dust removal mechanism

There are five types of dust removal mechanisms:

1 Inertial impact: smaller particles can pass through the pores of the filter element, but the path of the filter medium is tortuous, and the particles have sufficient mass and momentum to collide with the filter fiber and be blocked and captured.

2 Brownian diffusion: Very small particles have extremely small mass. When they do Brownian motion diffusion with airflow, they collide with filter fiber and are filtered out.

3 Direct blocking: For particles with dust particles larger than 1 micron, when they pass through the pores of the filter media material, the diameter of the particles is larger than the pore diameter, and they are directly blocked and blocked to achieve the purpose of removing impurities.

4 Gravity sedimentation: The dust particles continue to gather until their mass becomes sufficiently large. Under the action of gravity, they fall to the bottom of the filter or are discharged by the ash discharge valve.

5 Electrostatic settlement: Static electricity causes dust to change its trajectory and hit obstacles, and electrostatic force participates in the work of adhesion.