Large air separation FAQ - DEAR Air Separation

Pressure relays for large air separation units

A pressure relay is also known as a pressure switch. Its function is to cut off or switch on the current when the pressure is above or below a specified value to provide an alarm. The structural principle is that an elastic element (such as a bellows) works with a spring, and when the pressure increases (or decreases) to a specified value, it is transmitted to the micro switch through a lever mechanism, which turns the switch on or off to provide an alarm.DEAR air separation production of large ...

Jun 22, 2022

Forms of braking for large air separation unit turbine expanders

In order to consume the work of the turbine expander when required, to control the speed, to maintain the expander at its maximum efficiency point and to prevent the turbine from flying, turbine expanders are equipped with braking devices. There are three forms of braking commonly used on turbine expanders, namely pneumatic, motor and booster brakes. Most large oxygen generators use motor brakes, while booster brakes are a more advanced form of braking, which can recover the work of the expander...

Jun 20, 2022

Large air separation unit expander brake motor failure

The principle of the electric motor braking expander is to use the braking torque generated by the generator braking state of the motor to control the speed of the expander, if the braking motor fails, the expander speed will be out of control and it will overspeed. At this time, it is necessary to automatically open the protection control system, the method is that the speed measuring motor will send the overspeed signal, so that the three-way solenoid valve power off, the three-way solenoid va...

Jun 17, 2022

Temporary stopping steps for large air separation plants

When the large air separation unit needs to be temporarily stopped due to various faults, the following steps are to be followed.Stop the operation of each product compressor; stop the operation of the booster turbine expansion unit; stop the operation of the medium-pressure liquid oxygen pump; stop the operation of the medium-pressure liquid argon pump; stop the operation of the booster compressor unit; switch the instrument air system to the standby pipeline; open the air turbine compressor ou...

Jun 15, 2022

Pressure thermometers in large air separation unit

Pressure thermometers are made using the principle that the working medium (gas, vapour or liquid) in a sealed container changes in pressure as the temperature changes. In the use, installation to pay attention to the following issues.Filled with gas or liquid pressure type thermometer instrument readings not only with the temperature of the temperature packet, and by the capillary tube and spring tube temperature, that is, the impact of the surrounding environment temperature, although the use ...

Jun 13, 2022

Selection of Thermometers for Large Air Separation Plants

Resistance thermometer. It is composed of thermal resistance and its matching display instrument. The thermal resistance element is made of the characteristic that the resistance value of metal (or semiconductor) changes with temperature. Therefore, the change of temperature can be measured by measuring the change of resistance. Platinum thermal resistance (graduation number is Pt100) can be used to measure the temperature in the range of -200 ~ 650 ℃ in industry. In addition to the advantages o...

Jun 09, 2022

Why the high or low main steam temperature in large air separation units can affect the safe operation of the turbine

The turbine is used as a power source for air compressors in large air separation units, saving a large amount of energy for air separation users, and is a turbine-type mechanical device that converts the thermal energy of steam into mechanical energy. The main steam temperature or pressure has a direct impact on the safety performance of the turbine.In actual operation, as the steam inlet and high pressure parts of the turbine are in direct contact with the high temperature steam, when the stea...

Jun 07, 2022

Which seamless steel pipes are suitable for large air separation units？

Seamless steel pipes, the largest amount of industrial pipelines, the largest variety of specifications of the pipe.The seamless steel tubes for air separation equipment are carbon seamless steel tubes and high pressure seamless steel tubes.Carbon seamless steel pipe, commonly used manufacturing materials for 10, 20, 16Mn steel.Its specifications range from: hot-rolled outer diameter φ32 to 630mm, cold-drawn outer diameter φ6 to 200mm, single tube length 4 to 12m, allowable operating tem...

Jun 02, 2022

Design of the shape of the inlet and outlet gas lines of large air separation units

For the technical characteristics of non-standard large air separation units, combined with the actual use of the following aspects of the innovative use of new technologies and methods, design innovation to achieve the purpose of development.The shape design of the gas inlet and outlet pipelines of the adsorption tower focuses mainly on the design of a reasonable local proportion of the pipelines, under the premise of realising the process function. This improved design must combine engineering...

May 30, 2022

Research on the industrial design of large air separation units

DEAR Air has a number of patented inventions, of which the "ultra-low discharge pressure and energy saving patent" is the leading one in China. The innovative five systems are mainly achieved by reducing the discharge pressure of the air compression system; reducing the resistance of the air cooling tower of the encounter cooling system, the adsorber of the purification system and the flow meter of the control system; upgrading the fractionation tower system by replacing the upper tower, the low...

May 26, 2022

Standardisation of electrical processes for large air separation units

Centralised drainage design for the whole machine①For small air separation units and downhole equipment, a fixed and uniform centralised drainage outlet is designed on the skid block.②For large air separation units, the centralised drainage components are prefabricated in the workshop according to the design and taken away with the delivery, and then incorporated into the drainage line during installation on site according to the actual situation on the customer's side. Design of the operating ...

May 24, 2022

Reasons for main cooling of large air separation units without gas condensation

Addition of 3 brackets on the line before the liquid nitrogen into the liquid nitrogen metering tank. Add fixed racks on the main cold, liquid oxygen metering tank oxygen export line converge into out of the main cold before the oxygen main, add brackets on the lower tower. From the bottom to the top of the second elbow down about 1.5m of the liquid air out of the lower tower pipeline to add fixed brackets. Before the dirty nitrogen into the subcooler, the original bracket is changed to a frame ...

May 23, 2022

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