Large air separation FAQ - DEAR Air Separation

The role of pre-film of circulating water system in large air spearation units

The pre-film of circulating water system is to improve the film-forming effect of corrosion inhibitor. We often add a higher concentration of corrosion inhibitor at the beginning of the circulating water drive, and after it has formed a film, then reduce the concentration of the agent to maintain the replenishment film. This pre-film treatment is to quickly form a protective film on the metal surface, to improve the corrosion inhibitor inhibit the effect of corrosion.Practice has proved that in ...

Apr 08, 2022

Design basis for circulating water in large air separation units

According to the system water balance, water treatment to ensure that the circulating water system does not corrode and scale. Water treatment operation steps: flushing the system with clean water is to remove mechanical impurities and suspended matter from the system. When the water system is full of water, then turn on the pump to run. When the turbidity of the circulating cooling water system is high, drainage replacement is carried out. When the turbidity is below 20mg, then move on to the ...

Apr 06, 2022

Large air separation unit circulating water system scheme selection

The water quality of the cooling circulating water system is related to the safe operation of the large air separation unit. During the operation of the system, there are three major hazards commonly found in large air separation unit: scale, corrosion and biological slime, such as equipment scaling: corrosion perforation of water pipelines, scale and slime deposited on the packing that makes cooling towers work less efficiently. These hazards increase electricity consumption and also increase ...

Apr 01, 2022

Self-cleaning air filter in large air separation units

(1) In the box combination installation, the combined part of the clean air chamber should pay attention to. (2)the use of welding form, must be the net air chamber around the welding of the sealing welding (i.e. full welding), do not allow intermittent welding. (2)If the combination of gasket in the middle of the chamber is used, the bolts and nuts of the combination should be tightened. and can be sealed by injecting glass glue at the seam of the splice. (3) When installing the large a...

Mar 30, 2022

Filler liquid holding capacity of the large air separation untis

Under certain conditions, the unit volume of the packing layer, the volume of liquid accumulated on the surface of the packing and in the packing void is the liquid holding capacity of the packing. The liquid-holding capacity of the filler is related to the shape and size of the filler, the nature of the filler, the surface characteristics of the filler and so on. Also with the gas-liquid two-phase physical properties, the structure of the tower and the tower operating conditions. In practice, w...

Mar 24, 2022

Cold test of large air separation unit

1. Before the overall large air separation unit cold test. Fractionation should be fully heated and blown out. Air turbine compressor, turbine expander, air pre-cooling system, molecular sieve purification system and electrical, instrumentation and control system must be ready for operation. 2、The operation of the cold test is carried out in accordance with the operating instructions of the large air separation unit, in order to cool the distillation tower, the main condenser and othe...

Mar 23, 2022

Installation of the cold box of large air separation units

1 When installing cold box panels, the two adjacent sides can be pre-assembled on the ground as a whole or in angular form. The base frame and the skeleton section steel between with thin steel plate liner to adjust the box plate upper end surface level. 2 Cold box verticality. Verticality <1.5/1000, the total height deviation shall not be greater than 20mm 3 cold box sealing: the outer side of the skeleton between the use of full welding, intermittent welding on the inner side, to confirm ...

Mar 17, 2022

Throttle expansion versus isentropic expansion of large air separation unit

Isentropic expansion is more effective than throttle expansion in terms of temperature effect and cooling capacity. Moreover, the expander can also recover part of the expansion work, which can improve the economy of refrigeration. However, the throttling valve is simple in structure, easy to adjust and can work in the gas-liquid two-phase zone. Especially when the initial temperature is low, the cooling capacity of throttling is enhanced, isentropic expansion is weakened and the gap between the...

Mar 10, 2022

How do changing environmental conditions affect the performance of liquid air separation plant?

A decrease in atmospheric pressure will increase the compression ratio of the air compressor. A decrease in atmospheric pressure will increase the compression ratio of the air compressor by 6-8% and increase the energy consumption for compression. In addition, due to the increased mass to volume ratio (reduced density), the exhaust volume of the air compressor will be reduced and the relative oxygen production will be reduced, increasing the unit electricity consumption of oxygen production. Th...

Feb 21, 2022

Pump installation precautions for cold box of large air separation unit

Check the level of the liner seat, level it and then tighten the foot nut and fill the base with cement slurry. After cement leveling, check whether the bolt holes are loose, tighten them after checking for suitability, and then check the level. Coupling: The axis line of the pump and the axis line of the motor must coincide. This can be adjusted with thin shims. Measure the clearance of the two couplings, the difference between the maximum and minimum clearance on the plane of one week＜0.3mm, ...

Feb 15, 2022

Safety issues in the manufacture of large air separation equipment

The instrumentation pipe for pure argon towers and crude argon liquefiers should be led on the tower closest to the cold box, the lead pipe needs to be upwards. If the outlet of the instrument tube on the cold box plate is lower than the tower outlet and liquid and gas seals have to be made, upward shrinkage of the vessel has to be considered. The protection angle should be reversed to avoid the line being cut by the protection angle when the instrument tube is contracted upwards. With the cont...

Jan 27, 2022

What is meant by refrigeration and cooling capacity in large air separation plants？

According to the laws of thermodynamics, heat can only be transferred spontaneously from a high temperature object to a low temperature object, while the inverse process cannot take place spontaneously. A temperature lower than the ambient temperature cannot be produced without special methods. Methods of obtaining low temperatures have been mastered through practice. The process of obtaining a low temperature ...

Jan 26, 2022

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