Flow meter selection issues
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Process description: 40°C, 5% brine solution in 95% ethanol； Ethanol distillation using supergravity bed separation: 150 L/h of product obtained, with 400 L/h of reflux ； With the metal rotameter originally chosen, 5% saline solution causes salt crystals to form, which lead to blockages in the meter and the pre-filter; it only lasts for 5 to 6 hours before becoming clogged. The process and production teams considered that solving the issue of salting out was too complicated; they asked me to find a way to overcome the problems associated with low flow rates and salt buildup. I selected a process flow meter suitable for such conditions. The workshop reported that glass rotors could be used on site, but since salt adhered to the non-metallic floats, the flow measurement would likely be inaccurate as well. Do you have any good suggestions for selecting this flow meter?
With such low flow rates, most flow meters can be ruled out； Plus, due to possible crystal precipitation, a gate path needs to be selected ； Plus, the material may be uneven, so its electrical conductivity is uncertain ； Therefore, only mass flow meters can be recommended. Electromagnetic, wedge, and ultrasonic flowmeters can also be used, but they are likely to not work well
Given that brine can cause crystallization-related clogging issues, it is recommended to choose flowmeters with good corrosion resistance and ease of cleaning. The following types of flowmeters can be considered: 1. Electromagnetic flowmeter: Suitable for conductive fluids, such as saline water and alcohol solutions. It has no moving parts or flow path restrictions, so it is not prone to clogging. 2. Ultrasonic flow meter: Measures flow velocity using externally mounted sensors, suitable for liquids containing solid particles or crystals. No need to come into contact with liquids, which can reduce crystallization issues. 3. Rotating vortex flowmeter: It is suitable when the medium is a homogeneous liquid at high flow rates, and it also has a certain resistance to contamination of the medium. 4. Coriolis flowmeter: Suitable for applications requiring high precision, but it has a relatively high cost. It can resist crystallization structurally. When selecting a product, factors such as the installation location, temperature, pressure, and chemical compatibility should also be taken into consideration. Installing easily cleanable filters or using a regular backwashing system can also help reduce clogging caused by crystallization. .
Can heat tracing be applied to prevent the salt from crystallizing?