Vacuum degree of LNG storage tank

2025-06-03 | More News

LNG storage tanks are specialized pressure vessels used for storing liquefied natural gas (LNG), characterized by extremely high requirements for low temperature, high pressure, and safety reliability.They store LNG at an ultra-low temperature of -162°C to reduce its volume (the volume of LNG is approximately 1/600 of that of gaseous natural gas), facilitating transportation and large-scale storage.

1.What are the structural characteristics of LNG storage tanks?

Double-wall design:

Inner tank: Made of low-temperature-resistant materials (such as 9% nickel steel, austenitic stainless steel), directly contacting LNG.
Outer tank: Constructed from pre-stressed concrete or metal materials, providing structural support and thermal insulation layer protection.

Insulation system:

The interlayer is filled with insulating materials such as perlite and cellular glass, and vacuumized to reduce heat conduction (vacuum degree typically maintained at ≤5 Pa).

Safety accessories:
Equipped with pressure safety valves, level gauges, thermometers, emergency shut-off valves, etc., to ensure safe operation.

2.What types of LNG storage tanks are there, and what are their respective characteristics and typical application scenarios?

Type	Capacity Range	Typical Application Scenarios	Characteristics
Small-scale tanks	5–200 m³	Industrial users, gas stations, fuel storage for vehicles and ships	Mostly vertical cylindrical, made of stainless steel, movable or fixed installation.
Medium-scale tanks	200–1000 m³	Regional peak-shaving stations, LNG satellite stations	Vertical or horizontal, double-layer metal tank structure, increased insulation thickness to extend low-temperature retention time.
Large-scale tanks	10,000–200,000 m³	LNG receiving terminals, base-load gas storage facilities	Vertical fixed storage tanks, outer tanks made of pre-stressed concrete, inner tanks using 9% nickel steel, equipped with complex safety monitoring systems.
Membrane tanks	100,000–250,000 m³	Large onshore or offshore LNG storage tanks (e.g., floating storage tanks)	Inner tank uses metal membrane (such as Invar steel) as load-bearing layer, insulation layer made of polyurethane foam, saving materials and excellent thermal insulation.

Notes:

LNG Storage Tank Maintenance Regulations

Familiarize yourself with the structure and principles of the storage tank, and strictly follow the operating procedures for LNG-related operations.
Understand the performance and principles of tank accessories (pressure gauges, level gauges, safety valves, vacuum test valves), and regularly calibrate and test the tank’s vacuum degree in accordance with relevant national regulations.
Inspect the outer cylinder, process pipelines, valves, etc., of the storage tank every shift, and observe for any frost formation.
Use a ppm-level leak detector to check for leaks at valve and flange connections every week. Test the opening/closing actions of emergency shut-off valves and tank root valves monthly to ensure normal operation.
Regularly apply anti-corrosion treatment to the outer cylinder of the storage tank, and conduct visual cleaning and maintenance on the tank’s pressure gauges, level gauges, and thermometers.