Large capacity cryogenic lng storage tank

The purpose of the insulation design of LNG tanks is to meet the requirements of the production process, maintain and use the production capacity, reduce cold air loss, save energy, prevent condensation on the outer surface of the storage tank and improve the working environment. is. In the design of the refrigeration chamber of a cryogenic storage tank, the thermal insulation and cold insulation properties of cryogenic liquids must first be taken into account. Different structures and insulation are used accordingly for different storage conditions.

In the case of the cold insulation structure at the top of the storage tank, the cold insulation material covers the ceiling of the inner tank, so there is no need to transmit the pressure of the equipment or vaporized gas (insulation material itself), and the low temperature insulation material has low thermal conductivity. And must have low density properties. The upper part of the inner visor of the low temperature natural gas tank is made of 500mm cold insulated glass wool, and there are 5 layers with aluminum foil on the outside of the top layer of glass wool to prevent the expansion of perlite. Prevents other contaminants from entering the internal tank through the slot.

Foamed pearlite is selected as the insulation for the inner and outer intermediate wall layers, and the side walls are insulated by the foamed pearlite. After cooling the tank filled with the cryogenic liquid, the shrinkage of the internal tank causes the top and edge regions of the tank's sidewalls to be insufficient to fill the expanded pearlite, and the cryogenic tank then replenishes the expanded pearlite. Pre-cooling will not be possible. Applying a layer of flexible insulating fiberglass mat to the outer wall of the internal storage tank to prevent the ingress of moist air avoids refilling of pearlite and reduces the pressure of pearlite on the inner wall of the tank.

The design of the insulation and cold insulation structure at the bottom of the LNG storage tank should not only reduce the cold air loss of the storage tank slightly, but also ensure the compressive strength of the cold insulation material. Withstands the total weight and gas pressure of the inner container and cryogenic liquid. When designing and building a cold storage tank with a capacity of 200 m³, the bottom insulation structure is divided according to the principle of significantly reducing the various pressures and cooling loss factors at the bottom of the tank: Two parts. , Press ring and center ring and other cold insulation materials. Since the pressure ring is the main element that supports the weight of the inner tank and has relatively high strength requirements, we adopted a composite structure of concrete and glass brick as the cold insulation material for the pressure ring. In the central part of the bottom, the glass brick itself can meet the design requirements for strength and cold resistance.