Comparison between plate tower and packed tower
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Comparison between plate tower and packed tower ⑴ Plate tower should be used when the tower diameter is large. because: ①The cost of a plate tower based on unit plate area decreases as the tower diameter increases. The cost of a packed tower is proportional to its volume. The cost of a small diameter packed tower (below 0.8m) is generally lower than a plate tower. ②The larger the diameter of the plate tower, the more efficient it can be. The larger the diameter of the packed tower, the more difficult it will be to distribute the liquid evenly, and the efficiency will decrease. ③Maintenance of large trays is easier than cleaning of packed towers. ⑵When the required number of mass transfer units or theoretical plates is relatively large and the tower is very high, a plate tower is more suitable. In this case, the packed tower must be divided into many sections, and the liquid must be redistributed multiple times. Otherwise, the liquid will be unevenly distributed and channel flow will occur in the liquid or gas, which will affect the heat transfer efficiency. ⑶If heat must be removed from the tower, a plate tower is preferred because it is easier to install cooling tubes on the tower. ⑷The plate tower can adapt to relatively small liquid flow, but if a packed tower is used at this time, it will easily lead to insufficient wetting of the packing. ⑸The plate tower is suitable for handling liquids with suspended solids, and the packing layer is easily blocked by suspended solids. ⑹The plate tower facilitates side discharge. ⑺Packed towers are suitable for handling corrosive materials. If the trays are made of corrosion-resistant metal materials, the cost will be much higher. ⑻The pressure drop of packed tower is relatively small. During vacuum distillation, the pressure drop in the tower needs to be controlled to a very small value, and a packed tower can usually meet the requirements. ⑼The amount of liquid retained in the packed tower is relatively small, and the material stays in the tower for a short time, so it is suitable for intermittent distillation and the distillation of heat-sensitive materials. ⑽Packed towers are suitable for handling liquids that are prone to foaming.
Thanks for sharing. It seems that the content has increased when I made the ppt. I read some information and said that in some cases, a combination of mixed tower, plate tower and structured packed tower can be used.
It turns out that we generally use packing for small-scale distillation used in laboratories.
The summary above is very good, but there are a few points where I have different opinions: 1. Heat-sensitive materials are also difficult to process with packed tower distillation, and it is easy to block the tower, and it is troublesome and costly to replace the packing. 2. On the contrary, I think it is better to use a plate tower to handle materials that are prone to foaming. Packed towers are prone to flooding and blockage of the tower.
By reviewing the information on desulfurization, I found that there are other new forms of plate towers.: There are large orifice plates without overflow pipes available abroad, but I don’t know if they are also used in China.
The vast majority of domestic atmospheric desulfurization still uses packed towers. As for pressure desulfurization, the QYD mass transfer internals developed by our company for shift gas desulfurization in fertilizer production are plate towers, which have obvious advantages.