The issue of outlet pressure of the forced circulation pump in a negative-pressure tower as a centrifugal pump
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The pressure inside the tower is -0.09 Mpa, and the liquid level (water) height inside the tower is 2 m. After exiting the tower, the fluid goes to a circulation pump, which is then connected to a heat exchanger; the heat exchanger is linked to the bottom of the tower through outlet pipes. In this scenario, the pump provides the necessary pressure head for forced circulation. If the pressure loss in the heat exchanger and throughout the piping system is 30 kPa, then can we consider the pump’s outlet pressure to be -0.06 Mpa (the tower pressure plus the pressure loss), while the pump’s inlet pressure is -0.07 Mpa (the tower pressure plus the liquid level height)? In other words, the fluid gains 10 kPa of energy as it passes through the pump, and the pump’s outlet is also at negative pressure. Is this correct?
Do you think that with a pump head of 1M, circulation will be possible?
10 kPa corresponds to 1 m. I agree with you; the key point is that the pump’s outlet is under negative pressure, right? To determine whether the centrifugal pump is functioning properly,
This is a closed-system; the pump head is primarily used to overcome pipeline losses and the vertical height difference in liquid level.
Well, yes, so the outlet of the pump is actually under negative pressure, right?
It’s true that the outlet is under negative pressure, but the head cannot be that low
How can there be negative pressure at the pump outlet? It’s normal for the pressure to be positive after the pump does its work; moreover, the pressure must overcome losses in the pipelines before the fluid can circulate inside the tower
It should be negative pressure; there is negative pressure throughout the system, both before and after the pump. If it were positive pressure, then the material at that temperature would not contain any gas
Is the pump working properly? I’ve never seen such a technique; can a medium still flow and circulate under negative pressure?
Since the system connected to the pump is already under negative pressure, if a pump is installed in the reboiler at the bottom of that vacuum distillation tower, both the inlet and outlet will be under negative pressure as well
What kind of pump? I’ve never seen a pump for pumping liquids that operates under negative pressure; I’m curious