How to improve the stripping efficiency of a distillation column?
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Given that the tower configuration is fixed and the feed position cannot be changed, and since the feed has become lighter, it is necessary to improve the distillation efficiency – what should be done in this case?
The feed becomes lighter; if the feed rate remains unchanged, I believe the load on the distillation section increases while the load on the stripping section decreases. It is necessary to increase the opening ratio of the trays in the distillation section as well as the bottom gap of the downcomer, while the stripping section can remain unchanged； Due to the increased load on the distillation section, the reflux flow rate can be appropriately reduced; otherwise, the load inside the tower will be too high, and it will not be possible to increase the processing capacity. I’m not sure from which perspective the original poster is thinking when asking about improving the distillation effect.
The meaning of LZ isn’t quite clear. Does “the feed becoming lighter” mean that the amount of feed is decreasing? And does wanting to improve the retention effect mean aiming to increase the purity of the heavy components?
The composition of the feed becomes lighter. Doesn’t the book state that to achieve this, the feed position needs to be moved upward and the number of stripping trays increased? It seems to be the opposite of what was said on the second floor – what’s going on?
As the light components in the feed increase, the tower temperature drops, and the content of light components at the bottom of the tower increases; however, the light component content in the liquid at the bottom of the tower also rises. Therefore, to maintain the original efficiency of the distillation section, it is necessary to increase the heat load at the bottom of the tower.
If it is a packed tower, the packing in the stripping section can be replaced with high-efficiency packing to increase the number of theoretical plates. Raising the feed temperature and reactor temperature helps.
My previous statement might not have been correct; as the amount of light components increases, the total volume of light components carried to the stripping section rises as well, which increases the load on that section. Therefore, it is necessary to increase the steam supply to the reboiler at the bottom of the tower in order to vaporize these light components. Otherwise, the reactor temperature will drop, and the liquid at the bottom of the tower will contain a large amount of light components, resulting in high losses.