What are the safety protection devices for chemical storage tanks

To ensure the safe operation of chemical storage tanks, nitrogen blanketing should be installed between the inner and outer tanks to maintain a positive pressure in the interlayer, preventing the ingress of moist air and ensuring the excellent thermal insulation performance of the chemical products. In addition to this, what other safety protection measures should be implemented in chemical storage tanks.

For example, a double-layer liquid level alarm interlock system should be installed in the inner tank of chemical storage tanks. When the liquid level exceeds the set value, a high-level alarm is triggered. Upon reaching the high-high level, the interlock system activates, shutting off the valves on the liquid inlet pipelines of the chemical storage tank.

When the liquid level in the chemical storage tank falls below the set value, the low-level alarm is triggered. If the level reaches the low-low threshold, the interlock system activates, shutting off the valves on the discharge pipeline of the chemical storage tank and stopping the loading pump. Additionally, a dual pressure monitoring and interlock system may be installed. When the pressure in the chemical storage tank exceeds the set value, the high-pressure alarm is activated, triggering the interlock system to cut off the automatic valves on the pipeline of the liquefied natural gas storage tank's pressurization system and halt pressurization.

When the pressure in the chemical storage tank falls below the set value, initiate the low-pressure alarm and open the reflux control valve at the BOG compressor outlet to prevent the inner tank pressure from forming a vacuum. If the low-low pressure threshold is reached, activate the interlock system, open the automatic valve on the pipeline of the chemical storage tank pressurization system, and pressurize the inner tank of the vaporized portion of the chemical storage tank.

Not only that, the chemical storage tanks are equipped with a comprehensive safety system, consisting of dual safety valves and dual breather valves, which are switched using a three-way valve. When the internal tank pressure exceeds 25 kPa, the safety valves activate to release pressure; when the internal tank pressure falls below -0.5 kPa, the breather valves open to allow air intake, ensuring the prevention of equipment damage and issues.