Liquid Argon Atmospheric Storage Tank

Liquid argon atmospheric storage tank is an atmospheric pressure bimetal flat bottom tank used to store liquid low-temperature argon. It is generally bimetal structure. Pearlite is used to fill and insulate in the middle to ensure the low-temperature state of liquid argon in the inner tank, so that liquid argon is not easy to evaporate.

configuration parameter

Volume: 200 ~ 50000m ³ Working pressure: 10KPA ~ 50kPa

Insulation method: double wall powder accumulation insulation.

Basic types: ground setting type, high desk type.

Storage medium

Liquid nitrogen, liquid oxygen, liquid argon, liquid ethane, ethylene, etc;

Process flow system

Safe discharge system

Inner tank safety pipeline:

The storage tank should be equipped with perfect safety system. In addition to manual venting and automatic venting valve for automatic control of inner tank pressure, two sets of breathing valves should also be set and switched through three-way valve. When the inner groove pressure reaches 24kpa,

Breathing valve exhalation;

When the inner tank pressure drops to - 0.5kpa, the breathing valve inhales. When working, one set of two breathing valves must be opened to avoid equipment damage and personal injury. Suction only works as a last resort. Under normal circumstances, the top air pressure is too low, so long as the air is replenished through the self pressurization system.

The pipes leading out from the top of the inner tank adopt stainless steel bellows compensator for temperature difference stress compensation, and the bellows are set on the outer groove.

External tank safety pipeline:

The top of the outer tank shall be equipped with an emergency relief device (diameter: DN250) and a breathing valve (diameter: DN 150) to ensure the interlayer pressure within a certain range and the safety of the equipment.

Inlet system

Inlet pipeline:

The low-temperature liquid sent from the air separation unit area is sent to the storage tank through pipeline, and it is divided into two ways (top and bottom) before entering the storage tank for storage.

The liquid inlet system of the two atmospheric storage tanks in this project are all double way liquid inlet, that is, each storage tank is connected with two sets of air separation units, the liquid inlet system connected with each set of air separation unit is independent of each other, and each liquid inlet system has upper liquid inlet and lower liquid inlet, so as to ensure that there will be no conflict when two sets of air separation units feed liquid at the same time.

The liquid inlet of phase III air separation unit is reserved at the liquid inlet, and the stop valve is installed.

The top and bottom liquid inlet pipelines are provided with stop valve control; The ring spray device is used in the liquid inlet pipeline to the bottom of the storage tank to ensure the uniform cooling of the inner tank during the first liquid inlet and avoid excessive local temperature difference stress.

Filling system

Discharge line:

The liquid in the storage tank is discharged through the liquid discharge outlet at the bottom. The discharge pipeline is provided with a low temperature stop valve at the root, which is divided into two paths after leaving the root stop valve. A low temperature stop valve at the root is respectively provided to connect the inlets of two pumps.

Tanker pipeline:

The liquid in the storage tank is discharged through the Dn40 discharge port at the bottom. The discharge pipeline is equipped with a double low temperature stop valve and a quick filling joint for tank car connection,

The liquid discharge pipeline is also provided with a gas seal structure inside the equipment, which is led out from the bottom plate of the inner groove, so as to ensure that the liquid can be discharged completely; In order to facilitate the precooling and start-up of the pump, an anti swirl structure is set at the discharge port to avoid the cavitation of the pump.

Venting system

Inner tank vent pipeline:

When the pressure at the top of the inner tank reaches 20KPa, the automatic pressure regulating valve PCV1 is opened and the gas is vented. When the pressure in the tank is lower than 15kpa, the automatic pressure regulating valve (PCV1) is closed;

If the pressure continues to rise to 24kpa, the breathing valve S1 (DN 150) will open (V3 is normally open) to quickly empty and relieve the pressure. When the tank pressure drops, the valve S1 will close when it is lower than 24kpa. At this time, the manual vent valve V4 (DN50) can also be used for high altitude local discharge;

The venting of storage tank is controlled automatically by PCV1.

Self boosting system

The tank is equipped with self pressurization system. When the pressure in the tank decreases to 5kpa, the pressurization control valve PCV2 opens and the pressurization system pressurizes the tank. When the pressure reaches 10KPA, the control valve PCV2 closes; In case of unexpected failure, when the pressure continues to drop to - 0.5kpa, the breathing valve will inhale, control the control valve in the pipeline system of the discharge pump to close, stop the pump and stop the discharge.

Sandwich nitrogen seal

Interlayer nitrogen filling pipeline: dry nitrogen enters the interlayer space of the storage tank after being regulated by the self regulating valve and maintains a positive pressure state (less than 0.8kpa), so as to avoid the entry of humid air and maintain the good thermal insulation performance of pearlite.

The nitrogen consumption of interlayer is less than 10m3 / h

Other pipelines

Return line after pump:

The tank is equipped with two-way pump return pipeline, and the root valve is installed separately. The root valve is set on the return pipeline. The high vacuum insulation pipe is used for the part of the return pipeline leading out from the outer tank to the root valve, and the cold insulation pipe is used for the part from the root valve to the pump, so as to minimize the cold loss.

Gas phase pipe and liquid phase pipe of DN 15 storage tank: the storage tank is equipped with a set of gas phase pipe and liquid phase pipe, and the root valve is set respectively.

Full port of DN 15: the tank is equipped with full port of DN 15.

Liquid level and pressure indication system: in order to observe the liquid level and pressure of the storage tank, local instrument liquid level gauge and pressure gauge are set on the operation platform, which can directly monitor the liquid level, pressure of the inner tank and nitrogen pressure of the interlayer. At the same time, the liquid level and pressure of the inner tank are transmitted to the central control room through the differential pressure transmitter and the pressure transmitter to realize the remote monitoring of the central control room.