Regarding the installation of herringbone baffles in distillation towers
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As is well known, the main function of the chevron baffles is to provide a place for removing overheating and cleaning the catalyst. Recently, we have discussed another aspect: what factors were taken into consideration when designing these chevron baffles, such as the overflow strength? Or other factors? How to set it so as to reduce the pressure drop across the diagonal baffle while maintaining the desired effect. 1. What are the considerations? 2. How are the devices you are using configured? 3. Dear sea friends, what is the pressure drop across the diagonal baffles in your units? Those who have relevant data, please share it. 4. As shown in the figure below, which one has a greater voltage drop, P1 or P2?
This post was last edited by liaifeng on 2020-1-6 at 23:34. Haha, your question reminds me of a geometry problem my child had – figuring out which shape covers a larger proportion of the shaded area Through calculation, it can be determined that the proportion of shaded areas in these figures is the same; the same principle applies to the porosity of the distillation column you mentioned. When analyzing, I personally like to simplify complex problems first: based on the theoretical principles mentioned above, given the same material, this complex cross-section can be reduced to the form of a orifice plate. The porosity can be considered as the diameter of this orifice plate; therefore, with all other conditions remaining constant, no matter how many holes are created, as long as the porosity stays the same, the pressure drop before and after should be identical. (Ignoring some error factors), in our actual production process, the tray here serves as a site for gas-liquid contact, where mass and heat transfer occur between the gas and liquid phases. Relatively speaking, the higher the porosity, the greater the chances of contact between the gas and liquid phases, which in turn leads to an increased pressure loss. Therefore, under normal conditions, when the area and porosity are the same, the pressure drop across a tray with higher porosity should be greater than that of a tray with lower porosity. This situation is also consistent with the actual conditions of similar devices that we encounter in our daily work. There are many other factors to consider during engineering design; as long as the process requirements can be met, the simpler the equipment, the lower the relative manufacturing cost will be. The above are my personal opinions; I welcome any corrections from everyone.
Isn’t the diagonal baffle designed without any openings? If there are any openings, they are for drainage. So, the issue of porosity isn’t relevant here, right?
The pressure drop must be very small; with such large pores, I guess there is almost no pressure drop at all. The herringbone baffles are used for heat exchange calculations, and area is an important parameter. If improvement is needed, replacing it with Gritsch filler should yield good results.