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Centrifuging WVO before Conversion

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  • Centrifuging WVO before Conversion

    Has anyone thought of centrifuging their WVO to improve its homogeneity so as to provide a better "base stock" for conversion into biodiesel?
    They are used in the Tallow industry and the Vegetable Oil industry to purify their products.
    Such beasties are somewhat expensive, (even second-hand) but would remove so much contamination and variability of product as to make the processing more reliable and consistent - i.e. easier production of very high quality biodiesel along with higher quality glycerine by-product.
    One could be shared among a group of similar minded people as they also have a much higher throughput per hour than any other form of filtering.
    Any thoughts or specific knowledge?

  • #2
    Re: Centrifuging WVO before Conversion

    What a good idea !!

    How about an old washing machine on the spin cycle with the agitator removed and the inside of the drum lined with a cellulose filter material, you wouldn't be able to fill it up as it may be to heavy to get so much mass to get spinning

    any other suggestions ??

    Guess who's mum uses a whirlpool

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    • #3
      Re: Centrifuging WVO before Conversion

      When I mentioned centrifuging, I was thinking more along the lines of those specialist separator machines made by Alfa Laval and Westfalia. They operate at high rotational speeds (10,000 rpm for a small one) to generate the high centrifugal forces that are used to cause separation according to the varying masses of the mixed product entering the machine.
      Another possibility is to use the Centrifuges found on large trucks for filtering their Engine Oil.
      In each case one would need a feed pump of some kind and have the oil heated to some degree to enable the viscocity to not be a problem. With the truck centrifuges, they normally gravity drain, whereas the specialised separator usually can pump its output.
      I had not thought of your idea of a washing machine lined with filtering material, but I suspect that it would have some benefit over gravity feed through a filter medium.
      Look forward to hearing form others.

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      • #4
        Re: Centrifuging WVO before Conversion

        I have heard of a lady in Melbourne who built a great little biodiesel processor from an old twin tub washing machine. I have no info on it, but I'll chase up the person who told me offline and I'll see if they can post something up here about it.
        Robert.
        Site Admin.

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        • #5
          Re: Centrifuging

          Hi All.
          Re "The lady in Melbourne".
          Her name is Christa Blake, and from what i know, she is one of Australias pioneers in biodiesel, She designed the gold diesel plant.
          But she has suggested the best design of biodiesel plants (notwithstanding the need for great volume) is the old fashioned Twin tub washing machine.
          It doesnt create great volumes, but if your a back yard reactor why bother with volume greater than you can burn in one car.
          The old twin tub does need some minor modification , ie change the rubber hoses for polypropylene.
          The twin tub is already designed to handle slightly caustic water, (grey water).
          The spinn tub is already made of plastic so thats your methoxide mixer,, Simply spin cycle the meth and KoH back into itself to make methox solution then pump the methoxide into the agitation tub, with your heated oil. Some old twin tubs also have an inbuilt heater so there's your oil heated, otherwise you have to heat your oil beforehand before pumping into agitation tub.
          Once the reaction is complete simply spin cycle again your biodiesel into a settling tank.
          Now ofcourse this leaves out the water washing, but thats a whole other kettle of fish, and if your doin' a backyard job, why bother with tryin to meet Spec. .
          I have an old oil heater tank like you see on the side of 70's houses. It has an extra drain valve on the bottom , so i can do a water wash in that, simlpy attach to the end of a hose a misting nosle and stick the hose into the heater tank and drain of the water from the bottom. When the water drained of the bottom is nolonger white in colour, your biodiesel is washed and nolonger alkaline. Not that alkaline fuel bothers an old Merc. which has all metal fuel lines.
          Cheers all. Darren.

          Comment


          • #6
            Re: Centrifuging WVO before Conversion

            Another thought about centrifuge, A Bag sewn up to the dimentions of the washing machine bowl made from silkscreenprinting mesh. 150 t silkscreenprinting mesh fabric has a filiment grade of less than 5 microns.
            Buy it from any Art supply shop.

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            • #7
              Re: Centrifuging WVO before Conversion

              Fatman,
              With regard your suggestion of using a top-loading washing machine lined with some form of filter medium (even the silk-screen material as suggested by Darren which is something I know nothing about but find a facinating thought), my initial response was one that might have sounded dismissive. It was not meant to be.

              I was, and still am investigating the procurement at reasonable cost of a second hand centrifugal separator for use by a friend and myself in purifying WVO before we do anything further to it.

              However your suggestion has percolated away within my thoughts and I beleive that there is real value in using such a form of enhanced filtration in preparing the WVO.

              Firstly, a working second-hand top-loading washingmachine can be gotten for just about nothing, so that is a real plus.

              Secondly, although not generating many g's in tems of rotational speed, it would still vastly increase the effectiveness of the filtering process in terms of time saved over gravity feeding through a filter sock. This would especially be so if one was cold filtering, i.e. not preheating the received WVO to get only the lightest fractions of vegetable oil so as to minimise the issue of gel point of the biodiesel for cold weather use.

              Fatman, you were concerned about the ability of the washing machine to be able to spin the WVO when full. this would not be an issue as the machine is designed to spin up to full speed with a full load of sodden clothing in it.

              However, the beauty of using a washing machine is that you would not fill the machine and then begin it spinning. No, you would cut a hole in the lid to allow the WVO to be introduced into the spinning tub only when it was spinning at maximum speed. It could be introduced as fast as the small water pump at the bottom was able to pump it out (if it could??), or one could just raise the machine off the ground and gravity feed the filtered WVO into a clean container for further settling out of any supended water.

              The impeller would be removed and the WVO would be introduced into the centre of the rotating bowl which would allow multiple bags within bags so that the WVO was filtered through a number of increasingly finer micron filter layers. This would allow easier cleaning and longer intervals between the need to clean the filter material.

              One might need to jigger with the contoller to allow it to only spin and not go through the range of washing options, so as to allow it to just sit a spin until all the WVO had been filtered.

              Darren's idea of a bag fitted inside the bowl has the real advantage of allowing it to be easily removed for emptying the detritus from it (even rinsing it in biodiesel to clean it via the solvent capabilities of the biodiesel)

              Thanks for your suggestions Fatman and Darren. It is the unthought of things which, when recognised, can set in motion all manner of other processes of thought when seeking solutions to problems.

              In friendship

              Quentin

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              • #8
                Re: Centrifuging WVO before Conversion

                [QUOTE=CueBall]Fatman,
                With regard your suggestion of using a top-loading washing machine lined with some form of filter medium (even the silk-screen material as suggested by Darren which is something I know nothing about but find a facinating thought), my initial response was one that might have sounded dismissive. It was not meant to be.


                Hi Queball
                Even better, never thought of just adding the oil bit by bit, and those little twin tubs spin like the devil !!!! - there's a second hand washing machine guy just down the road - cool !!!

                PS
                Didn't think it was dismissive anyway

                PPS
                This is a forum after all, so your ideas will get dumped on from time to time, just grow a thicker skin !!!

                Regards
                The Fat Man
                Fat Man
                Junior Member
                Last edited by Fat Man; 4 January 2006, 12:09 PM.

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