Analysis of how hot and cold feeds are distributed in the tower
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The catalytic stripping tower has two feed streams: the cold feed enters at the top layer of the tower, while the feed after heat exchange enters at the 7th layer. Operating the stripping tower under low pressure and high temperature is advantageous; then why not use hot feed exclusively and eliminate the cold feed? Perhaps a higher temperature at the top of the tower results in a larger amount of gas being released; it might be possible to reduce the amount of steam at the bottom of the tower as well. In a stripping tower, unlike an absorption tower where liquid is fed at the top and gas at the bottom for mutual convective absorption, a stripping tower relies on heating from the bottom for separation. So, could the feeding point be moved to the middle?
This post was last edited by 176866346 on 2010-6-30 22:36. High temperature and low pressure are favorable for resolution, but there are limits to this. The stripping tower is used to keep the C2 content in the liquefied gas within acceptable limits; the reboiler at the bottom of the tower and the cold material at the top work together to regulate this C2 content. If only the reboiler at the bottom of the tower is used, without any cold material, it becomes extremely difficult to make adjustments when there are changes in the feed amount!
This post was last edited by BJYTABC on 2010-7-1 01:30. Introducing a small amount of cold material at the top of the tower is equivalent to introducing some reflux, which can help achieve a balance in the recovery process; it allows for the recovery of those components in the distillate gas that are above C3 level, thereby reducing entrainment and excessive distillation and increasing the yield of liquefied gas. On the other hand, it can reduce the load at the bottom of the tower and lower steam consumption, thereby achieving energy savings. The stripping column is equivalent to the stripping section of a distillation column, and its function is stripping. If the feed position is moved to the middle, then the separation tower becomes a distillation tower. It should be noted that the working principles of a stripping tower and a distillation tower are fundamentally different.
Reply 1# dxsy: Option 1 involves too much entrainment of recombinant components, while Option 2 has high energy consumption and a relatively complex process.
It’s not possible to change it to the middle section. In my opinion: 1. The separation tower functions as a retention section, with the purpose of separating C1 and C2. 2. Introducing cold feed at the top of the tower is done to control the separation temperature, enhance operational flexibility, and also to absorb C3. Everyone is welcome to share their opinions
What is the proportion of cold material? How should the cold and hot materials be distributed? 2:8? Or 1:1? Is 1:9 acceptable? Please also talk about your own installations. Thank you
I’m just starting to work with absorption analysis, so I have a question! Explain the specific principles and analysis process of Tad! Also, should a resolving agent be added? ?
I’ve tried to understand it on my own; if there’s anything wrong in what I said, please point it out and offer your criticism! Absorption goes without saying; countercurrent absorption is sufficient ； The separation takes place in the upper part of the tower: one feed stream, unheated, enters at the first tray at the top of the tower (the cold stream), while another feed stream, heated, enters at a position slightly above that but not at the first tray; the separation occurs through the packing and other media present in the tower, with the reboiler at the bottom of the tower and vacuum extraction at the top further assisting this separation process! Is that so? ? ?
Personal understanding: The principles of separation and distillation are different; separation aims to remove C1 and C2 while trying to maintain the amount of C3, without any process of purifying the heavier components. Therefore, there is no need for feeding in the middle as well. The top feeding section is intended to control the stripping temperature and prevent excessive stripping; it serves as a control mechanism, while the heat source provided by the bottom reboiler is where the stripping takes place.