1.2.3 LNG Storage Tank Gas Supply Process:

All valves on the tanks to be pressurized, except for the root valve and the emergency shut-off valve, are in the closed position.

2. Open the low-temperature tank's bottom inlet valve and the booster liquid and vapor phase valves, check that both valves of the booster vaporizer are in the open position.

3. Open the low-temperature cutoff valve before the gasifier, the normal temperature flanged ball valve after the gasifier, and all valves in the pressure regulating system that need to be opened.

4.A. When the gas supply is less than 1000-2000 Nm3/h, one storage tank is sufficient to meet the gas supply requirements.

5. Liquid Output:

5.1 When the tank pressure rises above 0.15MPa higher than the outlet pressure, gradually open the liquid outlet valve to commence the gas supply operation.

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

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

1.2.4 Operation Procedure for Self-pressurization of LNG Tanks

1. When manually operating, open the valves: the boost liquid phase valve, the boost gas phase bypass valve, and the liquefied gas entrainment valve. Allow LNG to directly enter the self-boosting gasifier, where it vaporizes and then enters the LNG storage tank. At this point, closely monitor the pressure; close the boost liquid phase valve when the pressure in the LNG storage tank reaches the required level.

2. Cautionary Notes:

(1) During operation, the LNG low-temperature storage tank must maintain a liquid level not exceeding 90% and not less than 15%.

(2) When manually operating the self-pressurizing system, the site must be attended at all times.

(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) During manual operation, the site must not be left unattended.

1.2.5 Risk Analysis and Countermeasures

When loading and unloading LNG tankers, operators should wear masks, antistatic work clothes, and frost-resistant gloves, etc.

2) When unloading LNG tankers, the vehicle must not move to prevent the pipeline from being pulled apart, which could lead to a large amount of 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 personal protective equipment. Static electricity from the human body must be neutralized before entering the station. Open flames are strictly prohibited within 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, follow the steps outlined in the operation ticket, and ensure a minimum of two on-site operators: one to perform and one to supervise, guaranteeing operation safety.

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

Low-temperature storage tank structure:

A low-temperature storage tank is a compact storage device for cryogenic 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. The tank can operate under low to medium pressure as per actual design requirements. Blasting discs and double-acting safety valves can protect the tank in case of excessive pressure. The safety relief device is designed to protect the internal pressure vessel and vacuum shell, and its use and models are determined according to the GB150 and "Fixed Container Regulations." This includes a double-acting safety relief valve and a blasting disc device for protecting the internal pressure vessel, as well as a blasting cap for protecting the vacuum shell (shell). The tank is designed and manufactured for safety, reliable operation, and durability (can operate without fault for many years). When operating the tank, strict adherence to proper safety and operating regulations is mandatory.

High safety requirements are in place. Since the tank stores low-temperature liquids, in the event of an accident, the stored liquid would evaporate greatly, with the vaporization volume being approximately 300 times that of its chilled state. This would form an automatically detonating gas cloud in the atmosphere. Therefore, standards such as API and BS require the tank to be of double-walled construction, employing the seal containment concept. In the event of leakage in the first tank wall, the second wall can completely contain the leaking liquid and the evaporated gas, ensuring storage safety.