I came up with a process and sought advice on its feasibility.
Thread Content
This post was last edited by holysong0 on 2020-4-15 08:52. It is a batch process; the tank contains a mixture of A and B with a boiling point of 35°C (A has a lower boiling point and is highly toxic). The mixture is stored at atmospheric pressure, while the tower that follows requires distillation under pressure, at 5 bar. I heat the tank using a hot water jacket to vaporize A and increase the pressure, thereby allowing the liquid to enter the subsequent tower. Are there any difficulties in terms of control? Is such a process widely used in industry? Could you give an example to boost my confidence? Thank you!
The pressure in the tower is 0.5 MPa; it’s practically impossible to achieve this pressure solely through the pressure of vaporization, as this would cause the liquid inside the tower to flow back upward
That makes sense, but I use batch distillation, and after distillation the pressure is reduced to atmospheric level. During feeding, the pressure in the tower is gradually increased from atmospheric pressure to 5 bar. Can this prevent role reversal?
Heating the gas in the front tanks to a pressure of over 5 bar can increase the liquid pressure at the bottom of those tanks, allowing the liquid to flow into the distillation tower behind. If the pressure in that rear tower is to be raised to 5 bar, then the entire tower must be filled with liquid. How can the distillation process be carried out under such conditions? If the rear tower is to operate at 5 bar, it is recommended to add 5 bar of nitrogen to the tower.
The first step is to press the material in the tank into the tower. The tower operates at atmospheric pressure, with an inert gas filled at the top of the tank to exert pressure. In the second step, the temperature of the tower is increased for distillation, and it is isolated from the tank.
Thank you, I’ll go with your approach for now.
1. Material A has a low boiling point and is highly toxic; nitrogen purging should be considered for the tank. 2. The tank is a pressure-rated vessel with a design pressure that is not very high, usually not exceeding 5 KPa. It is not feasible to use increased pressure in the tank to force the material into the distillation tower; instead, the material must be transported to the distillation tower either by pump or by gravity. 3. The distillation column should be equipped with a reboiler or heated before feed enters the column.
1. Is the heat exchange area of the tank sufficient? How much A needs to be vaporized at a pressure of 2.5 bar? 3. Factors such as pipeline pressure loss and the height of the equipment outlet also need to be taken into account