Selection of flowmeters under specific operating conditions
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Specific operating conditions: 40°C, 5% saline solution in 95% ethanol； Ethanol distillation in an ultra-gravity bed for ethanol separation: 400 L/h of product is collected at a flow rate of 150 L/h, with a reflux flow rate of the same amount; the static pressure difference before and after the flow meter is approximately 16 KPa ； With the metal rotameter originally selected, 5% saline solution causes salt crystals to form, which in turn lead to blockages in the meter and the upstream pipeline filters. This salt is insoluble in ethanol, and the blockages occur after only 5 to 6 hours at most. Process technology and production operations consider that the process for addressing material salting out is too complex; the instrumentation must find ways to overcome the problem of salt blockages, and process flowmeters suitable for these specific operating conditions should be selected. The conductivity of a 95% ethanol solution at 25°C is 2.6x10^-7 S/cm. I would like to ask my colleagues: what type of process flowmeter is suitable for this application? Automatic control instruments
Based on your description, salt crystal deposition and blockage is a major issue; in such cases, it is appropriate to use a flow meter that has no moving mechanical parts and is easy to clean. The following types of flow meters can be considered: 1. Electromagnetic flow meter: It is a good choice for conductive liquids (such as saltwater or ethanol solutions). Since there are no mechanical components, it will not be clogged by salt crystals. However, attention should be paid to conductivity; although 95% ethanol has a low conductivity, 5% saline solution may be sufficient to support the use of electromagnetic flowmeters. 2. Ultrasonic flowmeters: especially non-contact (clamped) ultrasonic flowmeters, as they do not come into direct contact with the fluid and are less prone to clogging. Suitable for cleaning and contaminated liquids. 3. Coriolis mass flow meter: It can directly measure mass flow, is less affected by changes in temperature and pressure, and is not sensitive to changes in the physical state of the medium (such as salt precipitation). When selecting a flow meter, factors such as the ease of cleaning and maintenance, corrosion resistance, and the ability to withstand the pressures and temperatures present in the process should also be taken into account. Special attention should be paid to ensuring that the material of the flow meter can withstand the corrosion caused by saltwater and ethanol. When making a specific selection, it is best to communicate with the manufacturer and provide detailed process conditions to obtain the optimal solution. .
If the pipeline is operating normally and not clogged, then a mass flow meter should work fine, right? Is it too expensive? ;P
An external-clamp ultrasonic flow meter can be chosen, eliminating concerns about clogging. If the budget permits, one can choose GE’s external ultrasonic flowmeter or portable ultrasonic flowmeter. ~~~~~~You can add me to find out more; we are a professional flow meter supplier, VX: gyqtbs008
For media containing easily precipitating crystals, the best flowmeters to choose are those without moving parts and that are not prone to clogging. Metal rotameters are not very suitable due to the possibility of blockage caused by their internal structure. The following types of flowmeters can be considered: 1. Electromagnetic flowmeters: Suitable for conductive liquids (such as saline-ethanol solutions), but the conductivity of the medium must meet the minimum requirements; the conductivity level you mentioned may not be sufficient to use a standard electromagnetic flowmeter. 2. Ultrasonic flow meter: non-invasive, has no moving parts, and is suitable for liquids containing impurities. Beams can penetrate media containing suspended particles, so they may be suitable for solutions with salt crystals. 3. Coriolis mass flow meter: It measures mass flow directly, is insensitive to changes in temperature and pressure, and has no moving parts, but it is relatively expensive. 4. Turbine flow meters: Although they contain rotating components, some designs are suitable for media that tend to crystallize; designs with wider flow channels can be chosen to reduce the risk of blockages. 5. Vortex flow meter: This type of flow meter can also be used if the Reynolds number of the liquid is within the appropriate range. It has no moving parts and is suitable for clean fluids; however, it may require a special design for fluids containing salt crystals. It is recommended to first test whether electromagnetic or ultrasonic flowmeters can meet the operational requirements, while considering the Coriolis mass flowmeter as a reliable but more expensive alternative. When selecting a flowmeter, it is necessary to ensure that its material can resist the corrosiveness of the medium, and the supplier should be asked to provide examples of applications in similar conditions along with successful experiences. .
Vortex flow meters probably won’t work; they tend to get stuck in the gaps of the vibrating element, resulting in large measurement errors