Supply of high-quality equipment for liquefied natural gas storage tanks under normal pressure and low temperature vessels

Description :

　　The large fluctuations in pressure of liquefied natural gas storage tanks in a short period of time are not conducive to stable production and increase energy consumption. The increase in tank pressure can further cause serious consequences such as compressor damage, rapid pressure reduction, and the possibility of creating a certain degree of vacuum in the tank, which is detrimental to the safe operation of the tank. Therefore, it is crucial to maintain controllable and stable tank pressure.

　　The design pressure of LNG refueling station storage tanks is 1.6MPa, and the operating pressure is 1.2MPa. The actual normal working pressure of liquefied natural gas storage tanks is between 0.4-1.0MPa. If it is low, it needs to be pressurized, and if it is high, it needs to be depressurized.

　　During normal operation, the operating pressure of liquefied natural gas storage tanks must be controlled within the allowable range. The normal working pressure range for liquefied natural gas storage tanks in southern China is 0.3~0.7 MPa. When the pressure inside the tank is lower than the set value, the tank can be pressurized using a self pressurized gasifier and self pressurized valve. The lower limit of boosting is determined by the opening pressure of the self boosting valve, and the upper limit of boosting is determined by the automatic closing pressure of the self boosting valve, which is usually about 15% higher than the set opening pressure of the self boosting valve. For example, when liquefied natural gas is used as the main source of urban gas, if the opening pressure of the self boosting valve is set to 0.6 MPa, the closing pressure of the self boosting valve is about 0.69 MPa, and the boosting value of the storage tank is 0.09 MPa.

　　The high working pressure of the storage tank is limited by the constant pressure value (front pressure) of the automatic pressure reducing regulating valve installed on the low-temperature gas phase pipeline of the storage tank. When the high working pressure of the storage tank reaches the set opening value of the pressure reducing regulating valve, the pressure reducing valve automatically opens to relieve pressure and protect the safety of the storage tank. To ensure that the booster valve and the pressure reducing valve do not interfere with each other during operation, the closing pressure of the booster valve and the opening pressure of the pressure reducing valve should not overlap, and a pressure difference of 0.05 MPa or more should be ensured. Considering the manufacturing accuracy of the two valves, the appropriate pressure difference should be determined during equipment debugging.

　　The liquefied natural gas receiving station is generally regarded as a backup warehouse for natural gas, consisting of LNG unloading section, tank evaporation gas processing section, LNG re gasification/export section, tanker loading and unloading section, and flare venting section, etc. The main body of the liquefied natural gas storage system is the LNG storage tank; Regardless of the mode of operation, switching, or stopping, it is all related to the storage tank. The storage tank is the most important body of the liquefied natural gas station, and LNG inlet and outlet, static and stop, fast and slow will all cause pressure fluctuations in the storage tank. When switching between different modes, the amount of evaporated gas in the storage tank will vary greatly, and the difference is huge, ranging from 1200kg/h to 7000kg/h. The pressure of the storage tank will fluctuate accordingly. Only by ensuring the stable pressure of the storage tank can normal production operations be carried out.

　　Therefore, to ensure the normal operation of liquefied natural gas stations, the first step is to ensure that the liquefied natural gas storage tanks are in a normal state, that is, to effectively control the tank pressure within the normal range through equipment.

AfterSalesService :

• Normal pressure of liquefied natural gas storage tank