Some discussions on tubular acid distributors
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I’m glad to have friends who can discuss various issues related to acid separators in my post from 2017 on acid separator design. I’ll make a summary post. The views expressed below are solely my own; due to my limited experience, I don’t have a thorough understanding of tubular acid separators, so my understanding might be inaccurate. I also hope that all experts can help point out any mistakes. The tubular acid distributor determines the upper limit of its distribution efficiency; no matter what changes or innovations are made, this limitation cannot be overcome. As factory technicians gain a better understanding of the drying and absorption system. 1. Better structured packing, 2. lower packing bed height, 3. lower pressure drop requirements – these are the goals that everyone strives for. 1. Better structured packing means that the acid separation points for the accompanying acid separators must be increased; 43P/M2 is sufficient at present. But what about 65P/M2? Even in chemical distillation towers, I need 200 P/M2. Is this achievable? Even if it’s possible in theory, what about the gas flow area when you arrange numerous main and branch pipes? How to solve the problem of acidic mist being carried along due to excessively high gas velocity? 2. A lower packing height means that the distribution effect must be ensured. Admittedly, at present, the operation of dry scrubbing systems involves a high acid feed rate; there are plenty of acid distributors capable of meeting this requirement. So, what about the situation where, in order to reduce the pressure drop by using structured packing, we also reduce the amount of circulating acid? Those who have access to tubular acid separators can give them a try on a test bench – is there any distribution deviation rate at a circulation rate of 3–5 m3/m2h? Is it possible to reach 3%? What about 1%? Moreover, a water medium is used. The density and viscosity of acidic media can be different. As a gravity-type distributor, the trough type also allows the liquid level to be adjusted after acid injection; once the deviation in the liquid level within the trough is below a certain value, the deviation in liquid distribution becomes essentially controllable. But how do you adjust the tubular type? 3. A lower pressure drop is even less achievable; in order to achieve a acid separation point of 43, the gas flow area inside the tower must **decrease**. What to do about tower pressure drop? How to solve the problem of acidic mist being carried along due to excessively high gas velocity? It is well known that sulfuric acid equipment features a special design: in traditional tubular acid distributors, the liquid overflows through upper openings into the acid discharge pipes; the acid sludge carried by the circulating acid can settle within the tank, thus not affecting or clogging the acid discharge pipes. I scrape the acidic mud out of the grooves every year, and it’s not difficult at all. If clogging needs to be addressed in pressurized equipment, the only option is to increase the filter surface area, raise the pressure, and boost the flow rate through the small pores. The power consumption associated with the additional pressure head must be significant, right? The director will scratch their head, and the boss will feel sorry. What should be done to address clogging issues during annual maintenance? Hang it up again, remove the tube, then scrape? Summary: Tubular acid separators sacrifice gas flow area and generate a large amount of acid mist to achieve their performance, whereas the channel-type type can achieve the same results more easily. What about when there are higher requirements? What to do if the downstream demister equipment is overloaded? What to do if the downstream equipment is exposed to acid? Is it convenient to carry out maintenance and clearing of blockages? Regarding the material issue as well, if truly innovative materials are available, then why not use them to create groove walls that are 1–2 times thicker, and tube walls that are 2–3 times thicker? If a thickness of 6–10 is required, is it due to casting issues or to leaving a margin for corrosion? Well, that’s unknown. Of course, it would be better if we could determine the annual corrosion rate under given acid conditions of temperature and concentration. The above are some of my immature opinions; I welcome everyone to discuss them together.
High-silicon cast iron, 1~2 mm thick?
High-silicon alloy: 1-2 layers thick wall grooves? ? ? ?
May I ask the original poster: Have you conducted the tower pressure drop test for what you call the tubular acid separator? What exactly is this pressure drop? If you haven’t done it, please don’t post blindly
The poster mentioned the generation of a large amount of acid mist. How is acid mist produced? Speaking purely of the acid distributor, does a greater thrust at the final outlet result in more acid mist? Then I have to ask the original poster: have you conducted tests on the final outlet pressure and flow rate for both the tank-tube type and what you call the tube type? If not, it is recommended that you test the data first before publishing it
Let’s talk about another data point related to tower pressure drop: how many manufacturers’ acid distributors are able to account for around 31% of the tower’s cross-sectional area? ? ? Please, the original poster, list them out
This post was last edited by springflower on 2019-8-17 at 18:06. Well, I’ll assume it’s 4 to 5 layers thick. Do you have the metal corrosion curve for your side?
Some companies do not need to fill the defoaming packing completely. The bottom of the groove has some flow area. Just because you don’t know doesn’t mean it’s not there.
Hey, stop being stubborn; the flow rate of a gravity acid separator can be calculated. It is the difference in height from the level of the clear liquid at the opening to the level of the final outlet; the pressure difference caused by 500 mmH2SO4 is not even enough to cause this difference. Just from those words of yours, I can tell that you really don’t understand the liquid distributor in distillation and absorption systems. Don’t tell me that a tubular acid separator can be operated without pressure? ? ? How can blockages be resolved without pressure? At least in my 5 years of experience in distillation column design, I have never heard of it. Searching for the book \"Tower Equipment\" in the upper static equipment area might be helpful to you.
The pressure drop is influenced by several factors: packing height, liquid flow rate, and gas flow area. Which type of tube can have an advantage? Can a tubular design reduce the packing height? Can a tubular design reduce the amount of circulating acid? Does a tubular design have a smaller gas flow area compared to a trough-type design? No need to measure; just give it a push.