Measurement methods for polypropylene powder silos
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In our unit’s polypropylene production facility, the level of the powder in the silo after polymerization is measured continuously using radar. For detecting the level, fork-type sensors and rotary impedance sensors are used. However, due to issues such as powder sticking to the walls of the silo and accumulation, these sensors do not perform well. I would like to ask those with more experience: are there any better methods for measuring the level in similar situations? Please advise!
Basically, this method of measurement you mentioned is used in all cases
I heard that many newly built polypropylene plants these days use a method of converting mass based on weight measurement; our radar currently doesn’t work very well
Is there a problem with the radar? ? ?
Of course problems arose; the measurement results were poor, with frequent fluctuations
For the silos, it’s not necessary to have such precise measurements; a few level switches will suffice. For critical applications such as those in extrusion processes, using a radiation source is sufficient
Supplying purge air to the radar transmitter head helps prevent dust from sticking to it, and this yields much better results.
Alas, sometimes it’s not up to us, who specialize in instruments, to decide whether something is critical or not; people simply demand that it function well. And when the indications from the switches and those from continuous measurement don’t match, there’s nothing you can do about it
Nitrogen purging has been applied, but the problem still exists. After checking, it was said that the main issue lies in the dielectric constant of the powder material
Polypropylene has a very low dielectric constant, making it unsuitable for radar use as it often causes signal loss. The current better approach is to use the relationship between the bottom echo reflection offset of the guided wave radar and the liquid level to perform back calculation. E+H’s guided wave radar has achieved good results in applications such as Beiyuan Chemical, which can serve as a reference.
Use a Rosemount 3D imaging level gauge – it’s designed specifically for use with dust and ensures high accuracy. Alternatively, an E+H guided wave level gauge can also be used. If you need help in selecting a product free of charge or want to obtain relevant information, feel free to contact me