Double liquid level alarm interlocking system for cryogenic storage tank

Cryogenic liquid storage tanks are widely used in the chemical industry. Because the storage medium is dangerous chemicals, in order to ensure the safe use of low temperature storage tanks. A nitrogen seal should be set between the inner and outer layers of the low-temperature storage tank to maintain the positive pressure of the middle layer to prevent humid air from entering and ensure the good thermal insulation performance of chemical products.
 
In addition, low temperature storage tanks need to be equipped with corresponding safety protection measures. The tank of the cryogenic storage tank should be equipped with a level alarm interlock system. When the liquid level of the low temperature storage tank is higher than the set value, the high liquid level alarm is activated, and when the high liquid level is reached, the interlock system is activated to shut off the valve on the low temperature storage tank inlet pipe.
 
When the liquid level in the cryogenic tank is lower than the set value, a low liquid level alarm will be triggered. When the low level is reached, the interlock system is activated, the valve on the liquid discharge pipe of the cryogenic storage tank is shut off, and the loading pump is shut off. In addition, there will be two sets of pressure monitoring and alarm interlocking systems. When the pressure of the low-temperature storage tank is higher than the set value, a high-pressure alarm will be triggered, the interlocking system will be activated, and the automatic valve on the pipeline of the booster system will be shut down to stop enhancement. When the low-temperature storage tank pressure is lower than the set value, a low-pressure alarm will be activated and the backflow regulating valve at the outlet of the BOG compressor will be opened to ensure that the pressure in the storage tank will not form a negative pressure. When the low pressure is reached, the interlocking system is activated, the automatic valve on the pipeline of the cryogenic liquid storage tank pressurization system is opened, and the cryogenic storage tank of the vaporization part is pressurized to the internal storage tank.
 
Not only that, there is a complete safety system in the chemical storage tank, that is, a double-group safety valve and a double-group breathing valve, and a three-way valve is used for switching. When the inner tank pressure exceeds 25kPa, the safety valve will release the pressure; when the internal storage tank pressure is lower than -0.5kPa, the breathing valve opens and air enters the internal storage tank to avoid equipment damage.