Anti-seismic structure for inner tank of double-hull cryogenic tank

Abstract

The invention provides an aseismic structure in a double-shell low-temperature in-tank tank. The aseismic structure comprises an anchor belt box, a cover body and an anchor belt, wherein the anchor belt box is arranged in a bearing table foundation, the top end is exposed out of the upper surface of the bearing table foundation and penetrates through an outer tank base plate to be in sealed welding to the outer tank base plate, the cover body is exposed out of the lower surface of the bearing table foundation and seals the bottom end of the anchor belt box, the lower end of the anchor belt penetrates the anchor belt box to be connected with the cover body, and the upper end of the anchor belt is movably connected with an inner tank wall. According to the aseismic structure, the anchor beltpenetrates the anchor belt box in the concrete bearing table foundation to be connected with the exposed cover body, the anchor belt is not in contact with the anchor belt box and is not in contact with the outer tank base plate, and the problem of low-temperature damage of the outer tank and the bearing table foundation due to the fact that cold of a low-temperature inner tank is transmitted toan outer tank and the bearing table foundation is solved; tearing force damage caused by the anchor belt to the outer tank base plate during an earthquake is avoided; the inner tank wall is movably connected to the upper end of the anchor belt, additional tension generated by the anchor belt to the inner tank wall can be avoided, the low-temperature inner tank is fixed during the earthquake, the earthquake force of a tank body is directly transmitted to a pressure bearing platform, and lift-off damage is prevented from being generated on the low-temperature inner tank during the earthquake.

Description

technical field [0001] The invention relates to the field of petroleum and chemical equipment, and more specifically relates to an anti-seismic structure for a double-shell cryogenic tank inner tank. Background technique [0002] In double-hull low-temperature storage tanks such as LNG, propane, propylene, ethylene, liquid ammonia, etc., in earthquake fortification areas, in order to avoid the lift-off force generated by the inner tank during an earthquake, the engineering is usually between the foundation of the outer tank bottom cap and the foundation pile. The method of adding shock-absorbing pads, instead of the traditional method of setting anchor straps on the outer tank, is to weld the anchor straps to the inner tank wall, and the lower end of the anchor straps is buried or passes through the cap foundation. Because the structure of the traditional outer tank with an anchor belt will cause great damage to the inner tank, resulting in potential safety hazards. Main ha...

AI Technical Summary

Problems solved by technology

However, the welded structure will inevitably transfer the cold energy to the bottom plate of the outer tank and the foundation of the outer tank after the anchor belt contacts the inner tank. The outer tank must use expensive low-temperature steel plates, and the anchor belt is buried or passed through the foundation. Many foundations may be damaged by frost heave

A large number of anchor belts will also cause a large loss of cooling capacity of the cryogenic tank body, resulting in huge economic losses for the entire cryogenic tank system

The second hazard is that one end of the anchor belt is welded to the bottom plate of the outer tank, and the other end is welded to the inner tank wall. During an earthquake, the inner tank is lifted away, and the anchor belt is used to fix the inner tank, so the tension is bound to be transmitted to the anchor belt and the outer tank bottom plate. The welding place of the inner tank will generate a large local stress, which will cause the two places to be damaged, resulting in leakage of the internal low-temperature medium, resulting in secondary hazards

The method of adding shock absorbing pads is feasible, but the shock absorbing pads are expensive, and many shock absorbing pads are damaged only after installation without earthquakes. They need to be replaced regularly within 20-25 years of service in the future, and replacement is very troublesome.

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