I would like to ask what causes the vapor phase in the distillation tower not to rise
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Let’s start by discussing the current process conditions: 1. There is a reactor, equipped with a crude distillation tower on top. The reactor has a volume of 20 cubic meters, while the crude distillation tower has a diameter of DN450 and a height of 9 meters. At the top of this tower, there are 2 meters worth of ceramic structured packing. 2. The required process conditions are now as follows: the temperature in the reaction vessel must be below 125 degrees Celsius. Since water is removed during the esterification reaction, isobutyl acetate is added to remove water through azeotropy (the azeotrope temperature between isobutyl acetate and water is 87.5 degrees; the boiling point of acetic acid is 118 degrees, and that of isobutyl acetate is 116 degrees). 3. Currently, the temperature in the reactor is 130 degrees, but the temperature in the middle and upper parts of the crude distillation tower fails to rise; it’s only around 60 degrees. It’s been over a day now, and there is no distillate coming from the top. Using a crude method, nitrogen was introduced at the bottom of the reactor through bubbling; the temperature at the top of the crude distillation tower rose to around 100 degrees. However, a strange phenomenon occurred: only isobutyl acetate rose to the top, while water hardly moved upward. I’m asking the experts here to explain what the reason is; I really can’t figure it out.
The vapor does not rise; the possible reasons are: 1. Insufficient temperature, resulting in inadequate evaporation； 2. The tower diameter is low, causing the gas phase to condense as it rises ； 3. The filler facilitates distillation in the gas phase as well as gas-liquid exchange, with the gas phase condensing during this process ； 4. As for isobutyl acetate appearing at the top of the tower, it is likely due to nitrogen entrainment rather than evaporation
Thank you. May I ask again if a smaller tower diameter also has an impact? The previous packing was 5 meters in diameter, and even when it was reduced to 2 meters, it still didn’t work well.
A smaller tower diameter will affect the gas velocity in the empty tower, which in turn affects the amount of gas that can pass through
Agree with the person above; your crude distillation tower doesn’t have insulation, right? The water condenses here. Water has such good fluidity that it flows back after condensing. The organic matter might have been carried away by nitrogen. Try to do a good job with insulation. The bottom temperature of the methanol-water tower is 120 degrees, while the top temperature is 60 degrees; as a result of separation, water is at the bottom and methanol is at the top. With this temperature gradient, it’s not easy to push the water upward
It’s insulated; presumably the filler type is incorrect, resulting in excellent heat exchange and phase change.
This is the typical production process for alkyd resins and polyester resins; the key issue is insufficient heating, resulting in too low temperatures. This reaction is also a reversible reaction; without the removal of water, the reaction cannot proceed.
There are many reasons why the light components don’t rise during distillation; is it vacuum distillation that you’re using? Is there a vacuum leak in the tower middle or at the top?
Check the components of the **boiling substances** in the reactor?