Does an MVR evaporator require a vacuum pump?
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Does an MVR evaporator require a vacuum pump? It depends on the operating conditions; either way is possible. What is the role of the vacuum pump here?
Without a vacuum pump, the operation will be more complicated and energy consumption will be higher
Where are vacuum pumps used? Is it a gas or a liquid?
Determine whether a vacuum pump is needed based on your evaporation temperature
Is the function of a vacuum pump to create a vacuum, thereby lowering the boiling point of the material? What other functions does it have?
So in an MVR evaporator, what is the role of the vacuum pump? Is it just to lower the boiling point of the material?
It depends on your process parameters; the key is the pressure at the inlet and outlet of the compressor! Under normal circumstances, the inlet pressure is always lower than atmospheric pressure. In such cases, when performing heat balance calculations and steam needs to be added, it is generally not necessary to use a vacuum pump to control the evaporation pressure ； What needs to be considered is the outlet pressure; if it is also below atmospheric pressure, a vacuum pump is required to remove the non-condensable gases. In some designs these days, vacuum pumps are installed without proper consideration, and the chosen models are often too large, which puts one in a difficult situation and leads to all sorts of embarrassing situations!
Some time ago, I came across a set of MVR units; the inlet pressure of the compressor was 70.2 kPa, while the outlet pressure was 125.1 kPa. A vacuum pump was also installed, and once that pump started operating, it became impossible for the outlet pressure to increase any further. Moreover, the vacuum pump chosen was too powerful; even with the vacuum control valve fully open, the pressure in the shell side wouldn’t increase by even a little. The poor amount of steam exiting was sucked away by the vacuum pump before it could even heat the heating tubes.
I’m currently facing the situation where I’ve chosen a vacuum pump that is too powerful, but I don’t know how to estimate the amount of non-condensable gas, so I’m unsure which vacuum pump to select
I would like to ask whether an MVR evaporator is considered a pressure vessel (low pressure)
SHTB-SZ-125 water-ring acid-resistant ceramic vacuum pump, suitable for pumping corrosive gases. The medium that forms the working water ring inside the pump can be clean water free of suspended particles, or it can be various organic or inorganic acid solutions free of suspended particles or crystals that do not react chemically with the gas to be pumped (with the exception of HF acid and hot concentrated alkalis). The water-ring acid-resistant ceramic vacuum pump is an ideal product for industries such as papermaking, pesticides, fertilizers, non-ferrous metallurgy, and chemicals, where it is used for vacuum dehydration, vacuum drying, vacuum filtration, and air compression. Since the water ring pump performs isothermal compression, it is particularly suitable for pumping flammable and explosive gases.