What’s the reason for the too low evaporation rate at the bottom of the DMF vacuum distillation tower?
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The evaporation rate at the bottom of the DMF vacuum distillation column is too low. The negative pressure at the bottom of the tower is around -80, and the temperature at the bottom of the tower is 108°C. It’s that the evaporation rate in Tari remains very low.
Could someone who knows something about distillation explain it to me?
The evaporation rate is low; either there is less steam, or the heat exchange area of the heater is undersized. Distillation manufacturers – you can message them privately
The heat exchange area of the tower bottom, the pressure of the heating steam, the vacuum level, and the load on the top condenser should all be checked
If the vacuum level remains stable but the evaporation rate is too low, it is necessary to consider whether there is insufficient steam from the heating source, or whether the heat exchange area is inadequate (insufficient area in the reboiler may be due to poor design or blockages in the heat exchange tubes); each case must be analyzed on its own
The possibilities are as follows: 1. The heat power at the bottom of the tower is insufficient, or the power is sufficient but the heat transfer area is inadequate； 2. The tower is not operating according to the design parameters; its diameter is too small, resulting in limited steam generation capacity ； 3. The content of light components within the tower is relatively low to begin with ；
There could be several reasons: 1. The composition of the feed has changed, deviating significantly from the design, with a low content of light components； 2. Blockage of the heat exchanger, insufficient heat exchange area, scaling on the heat exchanger, or too low a liquid level in the tower bottom may also be the cause.
As basically mentioned earlier, another possibility is that the check valve is to blame – it fails to drain the condensate in a timely manner, thereby affecting heat transfer.
I have also encountered this frequently during the calibration of our rotary bed.