Double-set liquid level alarm interlocking system for cryogenic storage tank

Cryogenic liquid tanks are widely used in the industrial field. In order to ensure the safe use of cryogenic storage tanks, nitrogen seals should be set between the inner and outer tank sandwiches of the cryogenic storage tanks to maintain a positive pressure state of the sandwiches to prevent the entry of humid air. In addition to the good thermal insulation properties of chemical products, what safety protection measures need to be equipped in low temperature storage tanks.

For example, the tank inside the cryogenic storage tank should be equipped with two sets of liquid level alarm interlocking systems. When the cryogenic storage tank liquid level is higher than the set value, the high-level alarm is activated, and when the high-level liquid level is reached, the interlock system is activated. Cut off the valve on the inlet pipe of the cryogenic storage tank.

When the cryogenic storage tank liquid level is lower than the set value, the low-level alarm is activated. When the low-level liquid level is reached, the interlock system is activated, the valve on the cryogenic storage tank drain pipeline is shut off, and the loading pump is closed. It will set up two sets of pressure monitoring and alarm interlocking systems. When the cryogenic storage tank pressure is higher than the set value, the high-pressure alarm will be activated, the interlocking system will be activated, and the automatic valve on the pipeline of the booster system of the LNG storage tank will be shut down to stop the increase. Pressure. When the cryogenic storage tank pressure is lower than the set value, a low-pressure alarm is activated, and the backflow regulating valve at the outlet of the BOG compressor is opened to ensure that the tank pressure in the cryogenic storage tank does not form a negative pressure. When the minimum pressure is reached, the interlock system is started Open the automatic valve on the pipeline of the cryogenic storage tank pressurization system, and the vaporized part of the cryogenic storage tank pressurizes the inner tank.

Not only that, there is a complete safety system in the cryogenic storage tank, that is, double sets of safety valves and double sets of breathing valves, which are switched by using three-way valves. When the internal tank pressure exceeds 25kPa, the safety valve starts to release pressure; When the inner tank pressure is lower than -0.5kPa, the breathing valve opens and air enters the inner tank to ensure that equipment damage and problems are avoided.