Professional Manufacturer of Natural Gas Storage Tanks - cabjehec

Low-temperature storage tank structure:

A low-temperature storage tank is a compact storage device for low-temperature liquids, equipped with various accessories (valves, safety systems, etc.). The tank consists of a carbon steel vacuum shell and a pressure vessel placed within it. It can operate under low to medium pressure as per actual design requirements. Explosion-proof plates and double safety valves can protect the tank in case of overpressure. The safety relief device is designed to protect the internal pressure vessel and vacuum shell, with its use and type determined by GB150 and the "Fixed Container Regulations." This includes a double safety relief valve and explosion-proof plate assembly for the internal pressure vessel protection, as well as an explosion-proof cover for the vacuum shell (shell). The tank is designed and manufactured for safety, reliable operation, and durability (can operate without failure for years), and strict adherence to proper safety and operational regulations is required during tank operation.

High safety requirements. As the tank stores low-temperature liquids, in the event of an accident, the refrigerated liquid would volatilize in large quantities, with the vaporization amount being approximately 300 times that of the refrigerated state, forming an automatically detonating gas cloud in the atmosphere. Therefore, standards such as API and BS require the tank to be constructed with a double-walled design, utilizing containment principles. In the event of a leak in the first layer of the tank, the second layer can completely seal off the leaking liquid and evaporated gas, ensuring storage safety.

1.2.3 LNG Storage Tank Gas Supply Process:

All valves of the tanks to be pressurized are confirmed to be closed, except for the root valve of the tank and the emergency shut-off valve.

2. Open the lower liquid inlet valve of the low-temperature storage tank, as well as the valves for increasing liquid and vapor pressure, and check that both valves of the pressure vaporizer are in the open position.

3. Open the low-temperature cutoff valve for the gasifier, the at-room-temperature flanged ball valve after the gasifier, and all valves required to be opened in the pressure regulating system.

4.A. A single storage tank is sufficient to meet the gas supply requirements when the gas supply rate is less than 1000-2000 Nm3/h.

5. Liquid Output:

5.1 When the tank pressure reaches more than 0.15 MPa above the outlet pressure, slowly open the outlet valve to initiate the gas supply operation.

5.2 Record the liquid storage tank number and the start of gas supply.

5.3 Pay close attention to the liquid level, pressure changes, and the flow and pressure variations at the outlet of the storage tank during gas supply.

1.2.4 LNG Tank Self-Pressurization Operation Procedure

1. During manual operation, open the valves: the pressure booster liquid phase valve, pressure booster gas phase bypass valve, and the liquefied gas entrainment valve, to allow LNG to flow directly into the self-pressurizing vaporizer. After vaporization, it enters the LNG storage tank. At this point, closely monitor the pressure. Close the pressure booster liquid phase valve when the pressure in the LNG storage tank reaches the desired level.

2. Cautionary Notes:

(1) During operation, the LNG low-temperature storage tank must maintain a maximum liquid level of ≤90% and a minimum liquid level of ≥15%.

(2) When manually operating the self-pressurizing system, it is strictly prohibited to leave the scene unattended.

(3) When the self-pressurizing system is in operation, the pressure-reducing system should be in the off state.

3. Important Notes:

(1) During operation, the LNG tank must maintain a liquid level of ≥15%.

(2) When manually operating, the site must not be left unattended.

1.2.5 Risk Analysis and Countermeasures

1) When loading and unloading LNG tankers, operators should wear masks, static-proof work clothes, and anti-freeze gloves, etc.

2) Absolutely no vehicle movement during LNG tank truck unloading to prevent bursting of loading/unloading hoses and massive LNG leakage.

3) When LNG is present in the pipeline, both ends' valves cannot be closed simultaneously.

4) Absolutely no touching or stepping on low-temperature pipelines and equipment.

6) Under no circumstances shall moisture, oil, mechanical impurities, etc., enter the pipeline to avoid blockage.

7) Absolutely no hammering, fire roasting, or water spraying on the frozen areas.

8) To ensure the safety of the working environment, operators must wear proper protective equipment. Static electricity from the human body must be neutralized before entering the station. Open flames are strictly prohibited in the station's operational area, as well as the use of non-explosion-proof tools and electronic devices.

9) Strictly adhere to the operation ticket system, following the steps outlined in the ticket. On-site operators must have at least two people: one to perform the operation and another to supervise, ensuring operational safety.

10) Conduct safety education before operation, implement on-site safety precautions effectively. In case of danger, know how to evacuate and control the situation.