Large air separation FAQ - DEAR Air Separation

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

Installation of large air separation plant

The installation of large air separation plant is an important link between the design and manufacture of ASU and the start of production, The quality of the installation work of Dear Air Separation ensures the operational index and safety of the whole set of air separation equipment in the future. In recent years, domestic and foreign manufacturers have encountered due to the quality of the installation of substandard ASU users and equipment manufacturers caused significant economic losses on b...

Jan 24, 2022

Cleaning and degreasing of pressure vessels, valves and piping of large air separation plant

Cleaning and degreasing of pressure vessels, valves and piping of large air separation plant 1 All pressure vessels, valves and pipelines and their piping accessories must be clean, dry and free from oil and grease before installation. 2 Degreasing of aluminium parts (pressure vessels, valves and piping) is strictly prohibited by the use of carbon tetrachloride. 3 Carbon steel oxygen piping outside the cold box, valves and all other parts with oxygen, must be strictly degreased before install...

Jan 21, 2022

Rapid development of large air separation plant import and export in China

In 1994, we exported a set of 10000m³/h air separation plant to India Esar Steel Company, which adopted the new technology of the fifth generation of air separation, showing to the world that the design and manufacturing level of China's ASU reached the international level at that time, creating a precedent for the export of large air separation unit in China. The first large air separation plant exported in China, to achieve a zero breakthrough in domestic large air separation plant into t...

Jan 14, 2022

Isothermal throttling refrigeration in large air separation plant

Isothermal throttling refrigeration in large air separation plant Air can be reduced in temperature by throttling, isothermal throttling is an isoenthalpy process and does not produce cooling. If the gas is to be cooled by isothermal throttling, it is compressed by isothermal compression and expanded by throttling. The enthalpy of the gas decreases during isothermal compression and the work of the compressor and the enthalpy drop of the gas are transferred to the environment together as...

Jan 10, 2022

How to clean vessels, valves and piping of large air separation plant?

All pressure vessels, valves and piping of small air separation unit and the vicinity of the piping (in contact with oxygen or cryogenic media) must be clean, dry and free from oil and grease before installation. Equipment that has been degreased by the manufacturer and is not contaminated can be installed without degreasing; if it is contaminated with grease, it should be degreased. materials such as aluminium and ma...

Jan 07, 2022

How to prevent water ingress accidents in large air separation plant？

Water ingress can have the following phenomena: molecular sieve pressure fluctuates from high to low, the resistance of the adsorber rises, and the temperature profile changes after heating and cold blowing. The most obvious change is a drop-in temperature after cold blowing and the appearance of a flat-headed peak. The longer the distance between the curves of the flat-head wind, the more water is f...

Jan 06, 2022

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