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Could the use of a 70 micron Element Filter (Wedge Wire), in place of a 25 micron Filter, for the filtration of hydrocracker unit feed, result in any problems?
 
Answers
15/12/2010 A: Mark Willingham, Purolator Advanced Filtration, mark.willingham@purolator-afg.com
If you are considering changing to a more open filter because of plugging problems with the 25 micron filters, perhaps you could consider alternative filter media. The use of our sintered wire cloth filter cartridges has proven to be very successful due to the construction of the media.

In this case, we would use a media construction with a very high permeability so the backwash cycle could be more effective. Our cartridges have replaced OEM cartridges and provided much longer run times between backwash cycles.

By using this design, it is possible to maintain a rating of 25 micron without the usual frequent backwash cycles typical of some porous metal filter designs.
23/03/2010 A: Niels van der Horst, Technisch Bureau Dahlman BV, n.vanderhorst@dahlman.nl
Normal common practice is the usage of 20-25 micron filters for feed filtration. However, the selection of the micron rating is depending on the licensor and catalyst supplier as well. In general it is wise to filter not too course so that less topping is needed and more catalyst can be used. A refiner makes his money with processing, not with having headaches over filters. Our aim is to provide the best filtration technology to refiners. Not every type of media is good to be used for feed filtration. Dahlman can perform on-site pilot tests. The unit can be hooked up to your process and different filter media styles and micron rating can be tested. Check points are filter efficiency, back flush efficiency, filter cycle times etcetera.
08/01/2008 A: Keng H Chung, Well Resources Inc, kengchung@hotmail.com
Before deciding what size and type of feed filter or even the feed filter application, you should know the nature of solids in your feed: type, amount and particle size distribution. Most of the filter vendors do not understand the characteristics of petroleum and are ill-equipped to determine the specifications of petroleum solids. Many refineries use the feed filters “blindly”, resulting in lost production and incurring unnecessary expenses in servicing the filter system.
08/01/2008 A: Eric Vetters, CorrMat International LLC, ewvetters@yahoo.com
Most refineries that increase filter screen size do so to reduce the frequency of filter clean outs/replacements. Assuming that is the case here, then your larger element size will allow more solids to pass and will increase the rate of pressure drop build in the hydrocracker reactor. If your current filter is not plugging, then there is little reason to go to a larger screen size.
If your filter is plugging faster than you like, then you are normally better off figuring out where the solids are coming from and dealing with the underlying problem, or else finding a different way to do the filtration such as changing to a backwash filter or using a filter than can hold more solids before the elements must be changed out.