Tank farm pressure transmitter problem
QUESTIONS: For a storage tank of 50 cubic meters, can the pressure transmitter be installed behind the nitrogen pressure reducing valve to accurately detect the real pressure of the storage tank? ? For example, when the tank area is pumping out, nitrogen is added to the inside, will the transmitter have negative pressure? But the true pressure of the jar is positive? ? ?
The installation position of the pressure transmitter cannot correctly detect the pressure in the tank. In general, the pressure in front of the self-operated valve is several thousand Pa, the pressure behind the valve is less than one thousand Pa, and the pressure in the tank is several hundred Pa. Make sure that the tank is slightly positive pressure, and the nitrogen gas is breathed out from the air. valve discharge. When the liquid material is discharged, the nitrogen supply volume is large, and the pressure behind the valve is large. When the material is not discharged, the nitrogen volume is small, and the pressure behind the valve is small.
The pressure transmitter should be installed on the top of the tank most suitably.
In fact, under normal circumstances, the differential pressure transmitter on the top of the tank measures the pressure on the top of the tank. The pressure point should be on the top of the tank and away from the nitrogen inlet, breathing valve and other openings. This is only an ideal state. If the process operates If you don’t pay attention, the nitrogen supply pipeline is generally below 40. Even if it is fully opened, it cannot meet the instantaneous change of such a large volume. Therefore, the process operation is more important. It is forbidden to add cold oil to the hot filling. It will not affect the sudden change of the pressure in the upper space. Only when replenishing materials, pay attention. If the temperature in the tank is high, do not add cold things into it. The hot air in the upper space shrinks sharply due to the cold. unbelievable. I have encountered a cylindrical storage tank with a diameter of 23 meters with a diameter of 5000 liters. In theory, such a large volume will not cause a sharp change in the upper space at all. Therefore, the nitrogen seal cannot be opened normally, and the oil measuring hole at the top is opened, and the diameter 250Mm, heat preservation in the tank at 80℃, process operation, add waste oil at 30℃ to the tank, the tank body explodes and sags inward, and the workers stop the operation.
