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Ethylene filtration

  1. Oct 27, 2006 #1
    I've a problem with dirty ethylene coming from compressors and blocking exchangers with dirt (some kind of soot or coke),so i'm looking for some kind of filter for ethyllene,anyone know for that kind of filters or where to find them?
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  3. Oct 27, 2006 #2


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    Hi malkio,
    In selecting a filter, you need to find one that matches the pressure and temperature of your process, and has a fine enough mesh to prevent particulates from passing that you know are in your system. Also, the materials of construction, including seals, need to be compatible with the fluid. And the filter must be large enough such that it does not present a flow restriction and won't get blocked between maintenance intervals.

    There are many good filter manufacturers, so I wouldn't look to any single one. Like any component, if you don't know what the best options are, you can create a specification for the component and request quotes from various suppliers.

    Do you know what size particles you have that need to be filtered out and where they're coming from? If the compressor is a recip, could it be the piston ring dust?
  4. Oct 30, 2006 #3
    Dirt is in form of C(Carbon) soot,coke and it's not so dry,i think there is even litle oil in that dirt.

    And yes it can be,(and i first suspected exactly this),from the guide ring (carbon-teflon) of recip compressor we use,but it's so much of that dirt that i don't believe it's all from just that ring.

    what i think is that some components in ethylene (methan,oil,..) cannot persist at that pressure (17 bar) and temperature,and breaks on C and H and that's where dirt comes

    i don't know exactly size of particle yet,but working on it.
    but could you give me some guidelines about suppliers,there are many companies,but don't see some dealing with my medium and problem,if you could recommend me something i''ll be grateful
  5. Oct 30, 2006 #4


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    Ethylene is C2H4 and exists as a gas at room temperature with a critical pressure of 742.7 psia and critical temperature of 49.8 F. It would appear you're operating in the superheated range (ie: ambient temperature and up to 17 bar) so almost any filter or strainer manufacturer can supply what you're looking for. Your contaminants are also fairly common, carbon, soot, coke, oil, etc… Piston ring dust is especially small which is why I asked. The finest filters, around 2 to 5 micron, will catch most of the ring dust but some will still get through. That might be true of the carbon dust you have too, but only by quantifying the particle size will you be able to know for sure. There are filters finer than that, but most manufacturers only have wire cloth down to about that level and I'd suggest you keep to wire cloth unless the final product requires even finer filtration.

    As for manufacturers, if you're in the US or Canada, I'd suggest starting with ThomasNet.
    Search on filters:
    or strainers:
    and find one that meets your needs. Don't worry if the company doesn't mention or advertise anything that is identical to what your problem is, you simply need to remove particles from a gas flow stream, and that's something they all do.

    Note also, carbon, oil or dirt is not going to break down nor become chemically bonded to ethylene gas. It is mechanically carried along by the gas, there is no chemical interaction. A wire cloth filter element will work fine for your application. You need to contact a manufacturer with such things as pressure, temperature, flow rate, quantity of contaminents, etc… I can't recommend anything without detailed information, but the filter manufacturer will be happy to ask you all sorts of questions about your application.

    You might also try the Engineering Tips forum for further advice.

    Good luck.
  6. Oct 30, 2006 #5


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    I am a student taking some fluid power courses, and we have talked a lot about filtration and purification. In the classroom, our instructor has been sayiong that the main device for purifying a fluid should not be a filter, but the resevoir. Do you agree with this premise (in general terms, of course)? And is there any way you could alter the pressure or temperature of the Ethylene so as to allow the contaminants to precipitate out?

    I haven't done much "real-world" work, only labs in a classroom. I'd really like to hea what someon with more practical knowledge has to say.
  7. Oct 30, 2006 #6


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    Hi Lurch,
    Note that filtration generally means particulates are removed from a fluid stream by mechanically blocking their travel, generally through the use of an element with small enough openings to capture particles. Purification generally means the fluid stream is subjected to various other non-mechanical means, for example: cryogenically freezing out a contaminant or creating some kind of chemical interaction to remove the contaminant.
    I wouldn't entirely disagree, but the way this is presented makes it sounds as if a reservoir is intended for use as a particulate separator. I've seen hydraulic reservoirs provided with internal filters, such that the 'filter body' if you will, is actually the reservoir. Perhaps that's what your instructor is thinking.

    In general, reservoirs of any kind, be it for a hydraulic system or a chemical process tank, are not suitable for separating contaminants for a number of reasons.
    1. They may be inaccessible for cleaning on a regular basis.
    2. To clean them would require the system be shut down.
    3. The cost of cleaning the reservoir would be prohibitive.

    It's possible to use a reservoir as a contaminant separator, and in a sense they are used as such, but if they are they're generally not considered reservoirs. In fact, tanks that store fluids of any kind are places where contaminants often are concentrated (as your instructor points out) and any portion of the system downstream will often need to be protected by placing a filter on the outlet.

    There are a lot of ways to remove contaminants, but from the description of the system above, it sounds like a simple filter element is the most economical way to go unless the particles are too small. That's a very real possibility. A molecular sieve is another common filtration means for removing the very fine particles such as carbon or piston ring dust. I don't see any way of altering pressure/temperature in this case though. Doing that isn't impossible but it wouldn't be economical.
  8. Oct 31, 2006 #7
    Q_Goest you're real helpful,tnx
    I'll find size of particles in my stream,and look for some wire cloth or molecular sieve filters if particles get very fine
    Just for links,I'm from europe:) so i'll try to find something similar here;)
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