山东LNG储罐厂家 30立方卧式LNG储罐 真空天然气储罐

LNG Tank Characteristics Requirements

Low-temperature resistance

The boiling point of liquefied natural gas at atmospheric pressure is -162°C. Therefore, LNG storage tanks must have excellent low-temperature resistance and superior insulation properties.

(2) High safety requirements

Due to the storage of low-temperature liquids inside the tank, in the event of an accident, the refrigerated liquid would evaporate in large quantities, with the vaporization amount being approximately 625 times that of the original refrigerated state, forming an explosive mixture in the atmosphere. Therefore, it is required that the tank be equipped with a double-walled structure and utilize the containment concept. In the event of a leak in the first layer, the second layer can completely seal off the leaking liquid and evaporated gas, ensuring the safety of storage.

(3) Special material.

The inner cylinder must be capable of withstanding low temperatures and is made of Austenitic stainless steel, while the outer cylinder is constructed from Q345R mild low-carbon alloy steel plate.

(4) Strict thermal insulation measures.

Due to the maximum temperature difference of up to 200℃ between inside and outside the drum, the drum must have excellent insulation properties to maintain a temperature of -160℃ inside. High-performance insulation material is filled between the inner and outer drums. The insulation material at the drum bottom must also possess sufficient load-bearing capacity. (5) Good seismic performance

The seismic requirements for general buildings are to crack but not collapse under specified earthquake loads. To ensure the safety of storage tanks under unexpected loads, they must possess excellent seismic performance. It is crucial to ensure that the tank does not sustain damage under the given seismic intensity. (6) Strict construction requirements

Tanks' weld seams must undergo 100% magnetic particle inspection (MT) and 100% vacuum leak tightness test (VBT). Strict selection of insulation materials is required, and the specified procedures must be followed during construction.

2. LNG Tank Structure

The low-temperature storage tank is a double-layered structure, with the inner shell designed to store low-temperature liquids, withstand the pressure and low temperatures of the medium, and is made of low-temperature-resistant alloy steel (0Crl8Ni9). The outer shell serves as a protective layer for the inner shell, maintaining a certain gap to form an insulating space, which bears the gravitational loads of the inner shell and the medium, as well as the vacuum negative pressure of the insulating layer. The outer shell does not come into contact with the low temperature and is made of container steel. The insulating layer is mostly filled with mica sand and subjected to high vacuum. The evaporation rate of the low-temperature storage tank is generally less than 0.2%.

Main components include: outer shell, inner shell, inner shell support, insulation layer, upper and lower liquid inlet pipes, upper and lower liquid level pipes, vapor pipe, overflow pipe, liquid outlet pipe, as well as safety accessories and instruments, etc.

山东LNG储罐厂家 30立方卧式LNG储罐 真空天然气储罐