Safety control system and control method for liquid level of large low-temperature liquid storage tank

Abstract

The invention relates to a safety control system for the liquid level of a large low-temperature liquid storage tank. The safety control system comprises three liquid indicators which are used for measuring liquid level and are respectively arranged in the large low-temperature liquid storage tank, wherein a servo liquid indicator, a radar liquid indicator and a magnetostriction liquid indicator are respectively adopted as the liquid indicator and are respectively connected with externally arranged control system and emergency shutdown system; the servo liquid indicator and the radar liquid indicator can carry out continuous detection on liquid level of 0-100%, while the magnetostriction liquid indicator downwards extends to be below the highest liquid level from a pipe opening at the tank top and can only detect the liquid level of 95-100% of the storage tank to be used for judging the highest linkage liquid level; the large low-temperature liquid storage tank is also internally provided with a low-temperature liquid pump used for sending out liquid in the storage tank and is connected with the emergency shutdown system; and the safety control system has the characteristics of being capable of ensuring that the liquid level of the low-temperature liquid is in a design scope, and being capable of achieving linkage cutoff by adopting dual systems, so as to effectively avoid the safety problem of the storage tank caused by too high or too low liquid level.

Description

technical field [0001] The invention relates to a liquid level safety control method applied to a cryogenic liquid storage tank system, and belongs to the technical field of large cryogenic liquid (such as ethylene, LNG) storage tanks. Background technique [0002] At present, storage tanks used to store cryogenic liquids are gradually developing into large-capacity prestressed concrete full-capacity tanks, and their scale has expanded from 20,000 cubic meters to 160,000 cubic meters and above; the working temperature of the stored liquid is lower than -100°C , and is a flammable and explosive gas. Once an accident occurs, it will not only cause huge economic losses, but may also cause losses to personnel and the environment. Therefore, the operation safety of large cryogenic liquid storage tanks has become the core issue, and the liquid level of cryogenic liquid storage tanks is one of the most important parameters for cryogenic storage tank detection. The liquid level of ...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a method that can ensure that the liquid level of the cryogenic liquid in the storage tank is within the design range, and adopts a double system for interlocking cut-off, so as to effectively avoid excessive liquid level or liquid level failure. Liquid level safety control method for large cryogenic liquid storage tanks with storage tank safety problems caused by too low

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