What are the requirements for the inlet temperature of a backwash filter?
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For the paraffin wax oil hydrogenation unit, the specified temperature for the backwash inlet is no more than 70 degrees. Why is that?
If the temperature is too high upon entering the buffer tank, the light components will evaporate; moreover, the feed pump has specific temperature requirements, as high temperatures can easily lead to cavitation
It’s a challenging task – during backwashing, there is severe water hammer and significant vibration. This is exactly the problem we’re facing here, and it still hasn’t been resolved.
If the temperature is too high upon entering the buffer tank, the light components will evaporate; moreover, the feed pump has specific temperature requirements, as high temperatures can easily lead to cavitation
Thank you all for your replies. I’ve taken a look, and it seems that the main reason is that part of the raw material is naphtha, which will vaporize at high temperatures; it’s not that the equipment cannot withstand such high temperatures Our requirement for the feed pump is that the temperature should not exceed 145 degrees. Our backwashing also has a steam flushing line, but it has never been used; we are concerned that the condensation of water vapor could lead to frequent flushing, and the raw materials may also contain water.
The design temperature for that area you mentioned should be greater than 70°, and it is likely related to the properties of the material you feed in. The heat exchange temperature at the backwash inlet can be adjusted appropriately according to the backwash conditions.
Personal opinion: The requirement regarding the inlet temperature of backwash filters is determined by the structure of the filter elements. Currently, the filter elements used are generally of type C, or what’s known as wedge-shaped mesh – namely the Johnson mesh! At high temperatures, the gap between the filter elements in this structure changes, which affects the filtering accuracy. So short-term overheating will not cause any problems. Individual filter elements that are made of sintered mesh are indeed very rare these days; they work fine at any temperature! ! Additionally, the 70°C requirement set by the landlord is indeed too stringent! Generally, around 100°C is no problem!