Desorption tower liquid level problem
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The liquid level in the desorption tower of our factory's CO2 stripping tower (no hydrolysis, steam is added at the bottom) has always been inaccurate. Operators generally operate based on experience, and now use double flange liquid level gauges. The main fault phenomenon is that the liquid level indication basically has no trend change. We analyzed that the main reason is that the liquid phase space at the bottom is short, about 1m, and it is a gas-liquid mixing zone with a high degree of turbulence. The instrument explains that the reason is the large density change. Please ask the brother manufacturer: 1. How is the liquid level of the desorption tower working? What type of level gauge is used? 2. Are there any distortions in history? If so, how were they resolved? 3. Is there any solution to this problem in our factory, including overcoming it from an operational perspective? Thanks! This post was last edited by Boating Five Lakes on 2009-3-9 10:51 ]
Generally speaking, desorption towers mostly use differential pressure level gauges. The author's double flange level gauge should be easy to use. The liquid space at the bottom is about 1m, which is completely enough. Shouldn't it be a gas-liquid mixing area? Does your steam bubble in? Don't take everything the instrument says. You can check the field transmitter and recalibrate the level gauge. Is the membrane head broken, silicone oil leaking, etc.? Ours is a pressure guiding tube type differential pressure level gauge, because the medium here is not likely to block the pressure guiding tube, and the effect is good. If sensitivity is the reason, you can also change the double flange to a direct pressure pipe.
Our factory is a deep hydrolysis device built in 1985. After the DCS transformation in 1996, the liquid level of the hydrolysis tower has been unstable and cannot be automatically controlled (very similar to the desorption tower situation mentioned by the poster). It was the same when it was later changed to double flanges. Last year, the conduit pipe was modified inside the tower, and the effect was very good. Specifically, a section of right-angle elbow with the opening facing downward is added inside it (lower flange conduit) in order to avoid the influence of vapor-liquid turbulence on pressure guidance. I wonder if the original poster’s equipment can also be modified in this way? It might be better to add elbows to both the upper and lower flanges (in opposite directions)!
Generally, the liquid level is controlled manually because the amount is variable. Best hand control
The steam in the desorption tower is bubbled in. After the overhaul, there is no problem with the transmitter. The liquid level gauge is normal when adding water. The membrane head problem can be eliminated. Let’s see how the situation is after this overhaul. Thank you for the analysis! It is a good idea to add an internal elbow pipe. When discussing with the instrument on-site, it was also mentioned that the lower flange should be moved to the elbow of the liquid outlet pipe (the elbow should be changed to a tee). However, at that time, I was not sure how effective it would be. It was just an idea! Thanks! This post was last edited by cthlj2007 on 2009-3-9 16:17 ]