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Pressure Safety Protection System For LNG Storage Tank

Mar. 11, 2019

Although the LNG Storage Tank has good thermal insulation properties, BOG cannot be completely avoided. Generally, the tank pressure control is slightly higher than the external atmospheric pressure by 5 kPa. If the BOG cannot be discharged in time, the storage tank may overpressure, and if the pumping capacity of the BOG compressor is too large, the storage tank may experience a negative pressure. Regardless of overpressure or underpressure, there is a serious threat to the safety of LNG storage tanks. 

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The general idea of pressure control of Cryogenic Mobile Tank is due to atmospheric pressure changes, material in and out, and normal pressure fluctuations caused by normal heat absorption to maintain tank pressure by adjusting the pumping capacity of the BOG compressor. In the extreme case of fire or tumbling, the tank pressure changes drastically, and it is necessary to set protective measures such as automatic venting valve, safety valve and breathing valve. Therefore, it can be divided into a conventional pressure control system and a pressure safety protection system. Conventional pressure control systems regulate the pressure of the LNG storage tank by changes in the pumping capacity of the BOG compressor. When the pressure of the LNG storage tank exceeds the adjustment capacity of the BOG compressor, the high pressure of the LNG storage tank must be automatically and safely discharged. The low pressure should close the compressor and replenish the natural gas in time.