Small air separation FAQ - DEAR Air Separation

Small air separation unit purification system overhaul program

The main elements of the analysis and development of the overhaul programme were First open the upper manhole of the purifier and check the bed leveling situation. If the bed is uneven, rake the bed. Add a few more drums of new molecular sieves. If the bed is collapsed, the lower manhole needs to be opened. Depending on the location of the bed leak, first plug the leak. Then rake out the leaking molecular sieve and observe its colour. If the leaking molecular sieve is black and yellow in colour...

Apr 29, 2022

Small air separation unit valve shell castings of various types of defective form and identification

1 Pore The image of the pore can be presented on the negative as an isolated or group of round, oval, pear-shaped dark spots, smooth contours, sharp images, the whole image blackness is large, no obvious changes. 2 Sparseness Sparseness is small, discrete holes distributed throughout the thickness of the casting. The image presented on the negative is related to the thickness of the casting. Thin sections may show up as fine reticulated images; thick sections will show up as faint dark spots,...

Apr 28, 2022

Liquid suspension in small air separation units

Small air separation units, large air separation units and liquid air separation plants in the distillation of the air separation tower, gas and liquid flow on the tower plate is very complex, must control the flow rate of gas. Too high or too low flow rate can spoil the working conditions of distillation. Liquid overhang is one of these abnormal conditions. In normal distillation, the liquid level on the tower plate is higher than the exit weir, and the liquid is not allowed to escape from the ...

Apr 26, 2022

Cooling fractionation tower system start-up issues in small air separation units

When the small air separation unit fractionation tower cooling start, in addition to into the booster compressor and directly into the air under the tower, air turbine compressor discharge air from the venting valve to keep the compressor discharge pressure unchanged. As the temperature of each part of the fractionation tower gradually decreases, the amount of air inhaled will gradually increase, at this time can gradually close the air compressor venting valve. When the cold end of the mai...

Apr 25, 2022

Why does the moisture content of air in a small air separation unit decrease after passing through a cooling tower?

The main functions of the air cooling tower: heat exchange, washing and buffering. In low-pressure small air separation unit, the absolute pressure of the compressed air discharged from the air compressor is around 0.6 MPa. After the air is compressed, the water content per unit volume increases so that its moisture content reaches the saturation content corresponding to the prevailing temperature. When the air flows through the air cooling tower, as the temperature decreases, the correspo...

Apr 24, 2022

What is the principle of screw chillers for small air separation units?

The small air separation unit screw chiller is named screw chiller because its key component compressor is screw type. Gas through the screw chiller unit, the evaporator out of the gas refrigerant, after the compressor adiabatic compression, into a high temperature and high pressure state of the gas. The compressed gas refrigerant is cooled and condensed in the condenser at medium pressure, which changes into liquid refrigerant after condensation. After condensation, the refrigerant is changed ...

Apr 21, 2022

What are the classifications of welded steel pipes in small air separations?

The specification range of commonly used welded steel pipes is 6 to 150mm nominal diameter Seamless steel pipes, which are also the most used in industrial pipelines, have the largest variety of specifications. The types of steel pipes are divided into two main categories: seamless steel pipes for fluid transport and seamless steel pipes with special features. The former is a steel pipe commonly used in process pipelines, the latter, such as boiler tubes, cracking furnace tubes and heat exchan...

Apr 20, 2022

What measures to consider for the transport and acceptance of oxygen piping materials in small air separation units?

Small air separation unit material production process should reduce grease and debris pollution and reduce the amount of subsequent processing works and processing difficulties. Small air separation unit material section in the factory before, transport and storage process using the adoption of strict closed measures to prevent secondary pollution. Specific measures are: Store small parts in pockets: Close the openings of the small air separation unit : Nitrogen sealing or drying and other metho...

Apr 19, 2022

Small air separation unit valve shell casting defect types

1 Pore Porosity is a hole formed in the casting when the gas in the molten alloy fails to escape during the solidification of the molten alloy. 2 Inclusions Inclusions are various metallic foreign bodies and non-metallic foreign bodies contained in the casting with a composition different from the basic composition, including metal inclusions, slag, sand. 3 shrinkage Casting molten alloy in the solidification process, because of the alloy liquid shrinkage and solidification shrinkage can no...

Apr 18, 2022

Safety hazards of valves for oxygen in small air separation units

Oxygen (including liquid oxygen) is one of the main products of small air separation units, but also a strong accelerant and strong oxidant. Grease, fibres and metals can become combustible in a high oxygen concentration. Once the valve housing for oxygen leaks out, oxygen leakage may lead to deflagration or explosion. Valves for oxygen in small air separation units as well as cryogenic valves require non-destructive testing of the pressure-bearing parts of the valve body for technical requirem...

Apr 15, 2022

Special requirements for the construction of oxygen in small air separation units

The structure of an oxygen press requires special requirements in order to ensure the safe operation of the oxygen press. Oxygen presses have a lower exhaust temperature than air compressors, so the number of stages is higher than for air compressors. Water lubrication or oil-free lubrication is required in the cylinder. The piston rod must be at least twice as long and have a well-sealed oil scraping device and an air leak recovery device. Any parts that come into contact with oxygen need to be...

Apr 14, 2022

Circulating cooling water system cleaning and pre-filming in small air separation units

Water circulation, whether it's new or old, requires system cleaning and pre-filming before dosing. The pretreatment of circulating water systems for chemical treatment includes cleaning work and pre-film work. For new systems, small air separation units and piping can sometimes have debris, debris and dust left in the system during installation, and sometimes cooling equipment can be heavily rusted and oiled. If these debris and oil are not cleaned, they will affect the next step of the pre-fil...

Apr 12, 2022

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