Vacuum pumping issues in multi-effect evaporators
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I’m facing a problem; I don’t know much about vacuum pumps, and I’m not clear about what exactly they can be used to extract. We are using a multi-effect evaporator; we want to install a vacuum pump in the last effect and no longer need a condenser. I want to know if it’s possible to use a vacuum pump to directly draw out the vapor from the separation chamber and then discharge it into another container for pressurized condensation.
Vacuum pumps are not designed for pumping steam; theoretically, the vapor should be condensed first. Vacuum pumps are used only to pump air
Vacuum pumps are used to evacuate only gases that do not condense and gases that do not react with vacuum oil.
It depends on the specific parameters; what is the vacuum level? To what pressure should it be pressurized? Is the cooling water temperature not low enough? Generally speaking, pumping out steam is very power-consuming!
The amount of air to be pumped out is very large, which requires a powerful vacuum pump – or several such pumps – and it’s essentially a matter of cost efficiency.
Yeah, if you don’t install a condenser in front of the pump, your investment will be very high. Large pumps are generally expensive, and electricity costs are also high
I learn from the forum*. I understand. Vacuum distillation system. The function of the condenser is to maintain a vacuum level during operation. The function of a vacuum pump is to create a vacuum level when the machine is started, and to maintain that vacuum level during operation.
Azeotropic evaporation – aren’t the condenser and vacuum pumping device (either a water ring vacuum pump or a rotary vane pump) standard equipment? It depends on how high a vacuum level you need
Condensation first, then vacuuming – this is essential. Firstly, the vacuum pump is used to remove non-condensable gases; such gases not only have a low specific heat capacity, but their accumulation in large quantities can also cause pressure instability inside the tank. The second factor to consider is that if the temperature is too high, the gas entering the vacuum pump chamber will directly heat the liquid within that chamber; at such temperatures, the liquid in the vacuum pump can flash vaporize, thereby reducing the pumping efficiency of the vacuum pump.
The optimal operating temperature for a vacuum pump is 40–50°C.