Discuss the energy consumption issues related to feed at the top and middle of the tower
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While discussing with a colleague today, there was something I didn’t understand; neither of us could convince the other. I’ve posted it on the forum, hoping experts can offer some guidance. It is now a distillation tower, with ammonia and hydrogen coming out from the top, and a mixed liquid (organic amine) coming out from the bottom. There is also a stream of return gas that comes from subsequent processes; its main components are ammonia and small amounts of organic substances, and its temperature is lower than that of the tower. There are now two feed inlets, one in the middle and one at the top. Which location is more energy-efficient for the gas to enter through? Personally, I think going in from above saves the energy needed to go from the middle up after achieving separation. Thank you first!
Cooling should be added from the top as much as possible, while heat should be added from the bottom of the tower; this helps to promote the formation of vapor and liquid phases and saves energy. It facilitates mass transfer.
This requires comprehensive consideration based on factors such as your feed composition, flow rate, temperature, and pressure; it is necessary to determine whether feeding from the top of the tower will ensure that heavier components are not carried away. Process operation parameters should be considered first, followed by energy consumption.
The reason for providing two feed inlets is to take into account the influence of heavy components; if there are heavy components, feeding is done from the middle, while if there are none or only a small amount, feeding is done from the top.
What was said on the 2nd floor is right; you’d better enter from the top
Feed based on the bubble point principle. It means that you feed the material in from the layer of the tray whose composition is most similar to that of the material there.