I’m seeking advice on selecting a level gauge for a crude distillation kettle; I’ve asked many people but haven’t found a solution.
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The size of the kettle is around 1.7 meters in height and 5 meters in length; there is a vertical tower tube in the exact center of the kettle, and heating tubes are inserted on one side of the kettle via bundles of pipes with a diameter of 0.5 meters. The heating source for the rough distillation process is 150-degree steam, while for distillation it is 380-degree heat transfer oil. The pressure is at atmospheric pressure during pressurized feeding; it is at a negative pressure of -0.1 during distillation in the feed tray of the column; and it is at a positive pressure of 0.6 MPa during tank cleaning. It is corrosive and coking-prone, similar to tar. Do anyone have any good methods for this liquid level issue? Flanges can cause the diaphragm to stick and crystallize, so double flanges are out of the question. The radar area is occupied by most of the tower tubes, and the heating tubes present inside can obstruct the ultrasonic radar. Experts, do you have any suggestions on what to do?
Some people might say that you need to weigh it. Well, let me speak on their behalf: I’ve been doing weight measurements for 15 years now. I’m as skilled at this as an old horse that knows the way, or a pig that can find corn with precision each time it digs. If you encounter difficulties while weighing and things don’t go smoothly, you can come to me. Whether it’s 30 grams or 300,000,000 tons, there’s nothing I can’t weigh. The method of using a small instrument for 1/N voltage division weighing to measure liquid level – it’s not clear who invented this approach first. As for utilizing weighing to determine the liquid level in spherical or horizontal tanks without relying on PCs or DCS systems or other complex large-scale devices, it’s likely that he was the first to do so; to this day, only a few people know how to use this method. The principle behind 1/N voltage division weighing is illustrated in the diagram below.
This post was last edited by 1111111 on 2019-4-30 at 23:13. Weighing is a project-based task that requires physical effort, and it’s completely not in line with my understanding of what small measuring instruments should do. I have Achilles tendonitis, lower back problems, cervical spondylosis… and I seem to have erectile dysfunction too? Hehehe :lol I really don’t have the physical strength or time to be on site taking care of weight sensors. So after stopping working in that field, I came up with an alternative approach: I used a sensor diaphragm that doesn’t come into contact with liquids, allowing for pressure measurement through gas isolation. This method was used to determine the liquid level in vacuum tanks as well as in vacuum high-temperature molten salt tanks. I sell my products to the Chinese Academy of Sciences. Take a look at the diagram – those who understand it will see the trick; those who don’t, just get lost :lol. The diagram shows 6 classic methods of pressure measurement, and the one used for measuring liquid levels is the second one from the right.
I have a question: in the process described above, where the system goes from a negative pressure state to a positive pressure state for purging and then back to a negative pressure state, even without an air-liquid level gauge, isn’t it still necessary to install valves in the measurement pipeline in order to create a vacuum? The question is a bit stupid. Also, what diameter should an air conduction tube generally have? I need to consider the issue of drilling holes in the pot.
1. Negative-pressure and dual-pressure (positive and negative) containers should be equipped with valves. If not added, when the vacuum in the gas phase is broken and positive pressure is applied, the liquid material may be forced into the small gas ducts, causing blockages. 2. The hole in the kettle should generally be over 70 mm in diameter.
1. With dual flanges and a flushing ring, injecting low-viscosity flushing oil can activate the function of the isolation diaphragm； 2. The quench oil units in ethylene plants are all designed in this way ； It works well ； 3. Select a capillary differential pressure transmitter with a large flange (3”) and high-boiling-point silicone oil ； The pipeline for flushing is equipped with a flow-limiting orifice plate and a rotameter.