Selection of level gauges for the bottom liquid level in high-viscosity tar-containing tower bottoms
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While organizing the work today, I discovered that there has been a persistent issue with the liquid level gauge in the bottom of one of the towers in this unit. Since I have no experience in the oil refining industry, I am unable to resolve the current problem effectively. The process design is described as follows: 1. This tower discharges material from its top, while the bottom of the tower contains heavier components such as organic substances, inorganic salts, and carbon-based polymers; due to the complexity of these components, they will not be described in detail here. 2. There are three level gauges installed at the bottom of this tower. The first one is an inserted differential pressure type level gauge, in the form of a diaphragm box combined with a transmitter; note that this level gauge does not have a root valve. The second one is a radar level gauge of the guided wave type, which does come equipped with a root valve. The third one is a magnetic flip board level gauge used on-site. 3. All three level gauges are equipped with heat tracing, using electric heat tracing of high power. 4. The tower operates under vacuum conditions, and the volume of the tower bottom designed for gas flow is quite large. Problems encountered: 1. Approximately 20 days after starting up the system again following a thorough cleanup during shutdown, the three level gauges begin to show distortions in their readings. 2. Since differential pressure type level gauges do not have root valves, it is not possible to clean them while the system is in operation; as a result, they are practically useless. 3. Radar type level gauges also experience problems from time to time due to the properties of the material being measured, but they need to be cleaned quite frequently. When the liquid level in the bottom of the tower is too low, the radar level gauge may also exhibit distorted readings due to issues related to gas flow. 4. Like the magnetic float level gauges used on site, radar level gauges also have a tube, and the float can get stuck, leading to inaccurate readings. I would like to ask the experts: regarding the operating conditions of such level gauges and the problems that arise, how do people design and select the devices used in their systems? Are there any tips for improvement? I would appreciate some advice. I do have some ideas at the moment, but I still want to hear everyone’s experiences and opinions before deciding on a plan for making improvements.
I’ve encountered a similar situation: a vacuum distillation tower in which the medium tends to crystallize. 1. The magnetic flap-based insulation and heating system does not work properly and has become useless. 2. The radar loses accuracy significantly during startup and shutdown periods; a flushing ring should be added to the double flanges in this setup (if it’s an insert-type design, it’s difficult to add one, so a flat diaphragm should be used instead), and hot water should be used for regular flushing.
It is recommended to install a radar level gauge; it can be added without shutting down the plant. Although the environmental regulations are rather complicated, and a license for handling radioactive sources is also required
Differential pressure level gauge; a blow-out type can be used
With its aggressive strategic approach, this product from our factory’s vacuum level gauges enables a simple solution: the sensor diaphragm is not in contact with liquid, thus achieving zero leakage; meanwhile, gas collection and pressure measurement are carried out in an isolated manner. The material adheres to the diaphragm easily – it can stick wherever it wants. In the pressure transmission tube, a pressure transmission path of 0.1 mm is sufficient! The level gauge can then measure it reliably. Tú Pò Lǐr said: .
If it’s a reactor with a stirrer, it can only be installed from the top and doesn’t have an insertion tube – how should this be handled?
For a reaction tank equipped with a stirrer, it is necessary to insert a sleeve from below the tank top, and then insert a pressure-taking tube along that sleeve. This is similar to the installation of submersible level gauges used in desulfurization lime slurry mixing tanks, where the sensor diaphragm does not come into contact with the liquid
1. It cannot be exposed to water; it is also a negative-pressure tower. 2. What is the shape and structure of the flushing ring used in such systems? Are there any reference drawings or photos available? Thank you
You can just search for it on Baidu; it can’t be exposed to water, but other liquid washes that are in use can be used instead.