Selection of the top condenser for the propylene distillation tower
Thread Content
This post was last edited by ahqjd on 2011-7-13 at 15:35. Organic solvent propylene is recovered through distillation; the feed is an aqueous solution of propylene, and the volume of material to be processed is large, so the distillation tower is of large size. Regarding the selection of condensers for distillation towers, large towers generally use shell-and-tube condensers. So which type of shell-and-tube condenser should be chosen? The temperature of the propylene steam at the top of the tower is in the high 50s degrees; if cooling water is used, the inlet temperature is around 30 degrees while the outlet temperature is around 40 degrees. The propylene flows through the shell side, while the water flows through the tube side. Given that propylene has a low flash point and is flammable and explosive, a stuffing box type with poor sealing performance is not used. Given the small temperature difference between the tube and shell, and from the perspective of saving equipment investment, a floating-head type is not selected. May I ask if a U-tube type can be used? Considering the fluid water cleaning in the tube bank, can an end-cap tube bank be used for the front tube bank? Should I choose a horizontal model? I would appreciate some advice from experts; thank you!
For the basic parameter combination of the U-tube type, the maximum pressure in the tube side is 6.4 MP. But we need a pipeline pressure of over 10 kilograms. Is the U-tube heat exchanger also not satisfactory?
Is a U-tube heat exchanger not used as a condenser? Are there only two types of shell-and-tube condensers: the floating-head type and the floating-head type with baffle rods?
In terms of condensation conditions, I have mostly worked with solvent recovery in pharmaceutical factories; for this type of material, its thermal properties result in a higher heat transfer coefficient compared to alcohols under the same conditions. Since the logarithmic temperature difference is not large, conventional shell-and-tube equipment with fixed tube sheets is sufficient. However, the inlet temperature of the cooling source provided by the poster is not very ideal; taking this into account as well as the cooling effect, the thermal driving force of the media on both sides will inevitably be low. Therefore, the heat exchange area required will be considerably larger when a cooler cooling source is used. This is also detrimental to the after-cooling at the backend (I assume your process design already takes into account the installation of after-cooling). Therefore, either low-temperature water should be added or replaced under summer operating conditions, or heat exchange equipment with enhanced heat transfer capabilities should be used, in order to achieve the specified process parameters within a confined space with a lower pressure drop, while also using less water. For this type of distillation process, where the materials are clean and have low corrosivity, I would like to recommend the internal finned heat exchanger (with numerous successful applications in similar scenarios). For more details, please visit the forum homepage: http://bbs.hcbbs.com/thread-163192-1-1.html
6.4MP = 64 kilograms, which is not enough if more than 10 kilograms are required?
We did not consider a tail cooler, as the non-condensable gases still return to the main air duct containing propylene, where they are adsorbed by the carbon adsorption bed. Does the inwardly facing fin require gas to flow through the tube side? 6.4MP can meet the high-pressure requirements, thank you.