Large air separation FAQ - DEAR Air Separation

The large air separation unit cold box maintenance work

The inspection work includes setting up scaffolding from bottom to top in the cold box and entering the cold box to check the specific damage to the piping. The liquid-air return pipe of the crude argon tower was bent and deformed, and the RTD cable on the liquid-air pipe was disconnected, and the safety valve pipe of the liquid-air steam of the crude argon tower was deformed and extruded together with the safety valve pipe of the condenser of the fine argon tower. The fine argon tower evaporato...

May 19, 2022

Fine argon tower pressure of large air separation unit

Large air separation units operator in the medium pressure system filling pressure, found that the pressure on the side of the fine argon tower has been rising, the final judgment of the fine argon tower evaporator has a string of leakage. So the workers cut open the evaporator barrel and found that the non-condensable gas blow-off tube was leaking in at the gap between the outgoing barrel and the casing. At the end of the overhaul sand picking, workers found that the non-condensable gas blow-of...

May 17, 2022

Large air separation unit argon purification stage

The cooling of the argon system of the large air separation unit should be carried out simultaneously with the cooling of the main tower system. After the cooling of the argon system, even if the argon system is not put into operation, a certain amount of cold should be introduced to the argon system to keep the argon system always in a cold state. Argon system can choose to adjust the pure and the main tower at the same time, more appropriate to wait for the main tower system adjustment is norm...

May 13, 2022

Low outlet pressure of piston type liquid oxygen pump for large air separation unit

Low outlet pressure is one of the common failures of piston type liquid oxygen pumps. The causes of low outlet pressure are usually wrong pump steering, insufficient speed, steam in the pump or a blocked inlet filter. If a piston liquid oxygen pump has a low outlet pressure fault, stop the pump to check the cause. If the steering is wrong, change the motor wiring. If there is steam in the pump, the exhaust line needs to be opened and re-cooled. If the filter is clogged, it needs to be disassembl...

May 11, 2022

Convective heat transfer in large air separation units

Convective heat transfer is one of the ways in which heat is transferred from a high temperature object to a low temperature object, using the flow of a fluid to transfer heat from one part of the fluid to another. The strength of convective heat transfer is expressed in terms of the heat transfer coefficient, which is influenced by the type of fluid. In addition to this, the state of flow of the fluid, the dynamics of the fluid that produce the flow and the shape of the radiating surface all af...

May 10, 2022

Tpes of weld defects in large air separation unit cast steel parts

ypes of weld defects in air separation equipment cast steel parts The morphology of cast steel defects on radiographs differs from that of welding defects, and the correct identification distinguishes the types of defects Inclusions 1 Metal inclusions Metal inclusions are mainly mixed in the casting metal melt in other kinds of metal pieces. It has a certain geometry, size of density and atomic number compared to the casting metal. Its image may appear as a lower or higher blackness th...

May 07, 2022

The purification system of the large air separation unit

The raw air is compressed to 0.50 MPa in an air compressor after passing through an air filter, cooled by a pre-cooling system, and then enters the molecular sieve adsorber for switching. After being pre-cooled and purified, the majority of the air eventually enters the fractionation column. The purification system has two molecular sieve adsorbers, one working while the other is regenerated (the large air separation unit uses the heating regeneration method) and the two adsorption drums work al...

May 05, 2022

Large air separation unit purification system carbon dioxide exceeds the standard problem analysis

The small air separation units, large air separation units and liquid air separation plants use ambient temperature molecular sieve adsorption purification, pressurized turbine expander cooling, liquid oxygen evaporator pressurization, gauge packing distillation, and DCS system control of the self-pressurization process. All systems are operating normally. The regenerated molecular sieves were not thoroughly regenerated and a vicious cycle occurred, increasing operating costs and risks. Operati...

Apr 29, 2022

What factors affects large air separation unit centrifugal compressor exhaust volumes?

Many factors affect the centrifugal compressor exhaust volume, in addition to design, manufacturing, installation, in addition to the operation of large air separation units compressor can affect the exhaust volume of the main factors are. 1) Air filter blockage or increased resistance, resulting in lower compressor inlet pressure. 2) air separation equipment pipeline blockage, increased resistance or valve failure, triggering the air compressor exhaust pressure rise. 3) compressor intercoole...

Apr 26, 2022

Selection of the illumination method for testing valves for oxygen in liquid air separation plants

According to the shape, size, location and protection conditions of the cast steel parts, choose the appropriate transmission method. In the case of implementation should be given priority to single-wall transillumination, in the single-wall transillumination can not be implemented before allowing the use of double-wall transillumination method. In practice, single-wall external transmission method, internal transmission eccentric method, internal transmission centre method, double-wall transmis...

Apr 25, 2022

What are the different types of steel plate coil tubes in large air separation units?

Steel plate coil pipe, which is rolled and welded from steel plates, is divided into two types of straight seam coil welded steel pipe and spiral seam coil welded steel pipe. LSAW steel pipe: most of the construction site manufacturing or commissioned processing plant manufacturing, professional steel pipe factory does not produce. Steel plate material Q235A, No. 10, No. 20, 16Mn, 20g, etc., its specifications range from 200 to 3000mm nominal diameter, the largest with 4000mm, wall thickness ge...

Apr 21, 2022

Safety measures for oxygen centrifugal compressors in large air separation units

Oxygen is a strong oxidising gas, flammable and explosive, so safety measures should be taken in its design and manufacture. When choosing materials, all metals in contact with oxygen must be chemically stable and not easily oxidised. Each component should be degreased. The shaft seal should be sealed with nitrogen pressure difference and also ensure the vacuum of the oil system. All large air separation unit parts and pipings in contact with oxygen should be earthed to prevent static electricit...

Apr 19, 2022

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