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Thread: Bio Sludge in fuel tank

  1. #1
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    Sep 2005
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    Bio Sludge in fuel tank

    Mark,
    What colour is the smoke?
    Have you checked the fuel filters?
    There can be a drop out over time, even from washed biodiesel, which could contribute to your problem. At our meeting on Sunday, a member brought in samples of biodiesel and a dark substance from the fuel tank, which accumulated over time, resulting in a 'failure to proceed' of his daughter's car. After towing it home, the IP was removed as it was not pumping fuel to the injectors. A substance had entered the IP and it had to be cleaned. The IP mechanic said it was very hard to remove and did not respond to the usual solvents they use.
    The samples provided were not water soluble and they remained oily but sticky.
    Do you know where we could get the samples tested to identify the 'drop out' and suggest methods to prevent it / clean it up should it occur.

    Tony
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles on oil based fuels:
    '85 Mercedes Benz W123 300CD Turbodiesel
    '98 Mercedes W202 C250 Turbodiesel (my car)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car) [sold]


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  2. #2
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    Re: Bio Sludge in fuel tank

    Who set up this forum? I composed a long and detailed reply, and I know what the black stuff is and what to do about it, but when I attempted to post it, I was told that I had to refresh and log in again. And as soon as I did that I lost everything I'd typed.
    Last edited by Tony From West Oz; 20th March 2017 at 11:02 PM. Reason: Re- titled to match new thread

  3. #3
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    Re: Bio Sludge in fuel tank

    I have never had to 'refresh' on the forum. There may have been a connection issue that caused it.
    You have learned a lesson. If you need to 'refresh' ensure you copy the post first. Some people prefer to write their posts on a word processor programme and then copy and past it into a forum post.
    Care to try again?
    Last edited by Tony From West Oz; 20th March 2017 at 11:03 PM. Reason: Re-titled to match new thread
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles on oil based fuels:
    '85 Mercedes Benz W123 300CD Turbodiesel
    '98 Mercedes W202 C250 Turbodiesel (my car)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car) [sold]


    Searching the Biofuels Forum using Google

    Adding images and/or documents to your posts


  4. #4
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    Re: Bio Sludge in fuel tank

    I'll just do shorter posts. The black slime is biomass, the ultimate product of using a fuel that is biological in nature. Only car I've ever had it happen on was my Triton for reasons that are as yet unclear. Solution is to remove the tank, drain the fuel, and then soak the tank in a dilute solution of caustic soda. The NaOH will convert the slime to a fairly rigid gel that will then lift away from the steel and float in a single mass so you can just lift it out with your hand. But then you have to do your fuel lines as well. It was so fine that it even got past my 1um Frantz filter, and ultimately killed the IP. I had seen this for a while - there was a fine black slime downstream of the filter element. At first I thought it was rubber from the fuel lines, but the penny eventually dropped, and when I emptied the fuel tank there was a covering of it sitting on the bottom.
    Last edited by Tony From West Oz; 20th March 2017 at 11:04 PM. Reason: Re-titled to match new thread

  5. #5
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    Re: Bio Sludge in fuel tank

    Quote Originally Posted by Dr Mark View Post
    I'll just do shorter posts. The black slime is biomass, the ultimate product of using a fuel that is biological in nature. Only car I've ever had it happen on was my Triton for reasons that are as yet unclear. Solution is to remove the tank, drain the fuel, and then soak the tank in a dilute solution of caustic soda. The NaOH will convert the slime to a fairly rigid gel that will then lift away from the steel and float in a single mass so you can just lift it out with your hand. But then you have to do your fuel lines as well. It was so fine that it even got past my 1um Frantz filter, and ultimately killed the IP. I had seen this for a while - there was a fine black slime downstream of the filter element. At first I thought it was rubber from the fuel lines, but the penny eventually dropped, and when I emptied the fuel tank there was a covering of it sitting on the bottom.

    Mark,
    This does not occur when using WVO, yet does after it is converted to Biodiesel. Can you shed some light the cause on the sludge occurring and any means to prevent its formation? Is this an issue with commercially produced biodiesel, here or overseas? If not, why not?
    Last edited by Tony From West Oz; 20th March 2017 at 11:04 PM. Reason: Re-titled to match new thread
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles on oil based fuels:
    '85 Mercedes Benz W123 300CD Turbodiesel
    '98 Mercedes W202 C250 Turbodiesel (my car)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car) [sold]


    Searching the Biofuels Forum using Google

    Adding images and/or documents to your posts


  6. #6
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    Re: Bio Sludge in fuel tank

    I forwarded the content of this discussion to members of WARFA. Here is a response from one of our contacts:
    I find sedimenters are very important in Biodeisel systems and veg oil systems!
    Even with one, it ( Glycerine as I believe it to be ) still falls out of suspension after 6 months of settling and can still bypass the primary sedimenter and accumulate in my filter!
    I also understand that professionals are loath to store Biodeisel long term ( over a year ) due to possible problems.... can't recall what but assumed it was degradation of fuel....


    My solution is to regularly drain both my inline sedimenter and recommend (but don't do it myself, ones fuel filter between services and to use almost a full tank to almost empty before I refuel regularity. I also flush a tank of diesel through every 6 months as a precautionary measure!

    5 years on last vehicle, two tank system bio diesel and wvo ( filtered) and steel tanks sparkling clean!
    Does anyone else have any suggestions?
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles on oil based fuels:
    '85 Mercedes Benz W123 300CD Turbodiesel
    '98 Mercedes W202 C250 Turbodiesel (my car)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car) [sold]


    Searching the Biofuels Forum using Google

    Adding images and/or documents to your posts


  7. #7
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    Re: Bio Sludge in fuel tank

    Well I always considered the black sludge to be glycerine. I dont wash my fuel so I do get a continuing drop out in my storage tanks (1000 L IBC). I recently installed a 'glycerine trap' inline before the bowser pump. I used a 20l steel tin as I have plenty of these (it also doesnt flatten with the suction of the pump like a plastic cubie will) and it just acts as big chamber to slow the fuel down on its way so the crap that drops out falls into the accumulator rather than blocking my golden rod filter. Glycerine used to make it past the filter and into my tank, before being caught in my cav glass bowl.

    Since installing the glycerine trap the amount of glycerine in the cav filter bowls have definitely reduced, but its still there. I tend to think that maybe the additional 'processing' that is occurring in the car (agitation from driving, facet / walbro pump and then the lift pump in the IP - all coupled with heating from the IP engine block - then return to the tank) continues to convert the fuel on the run and improves my fuel quality!!!!

    One possible concern with long term storage of biodiesel is if its being stored its not being sold, so your return on investment is poor. I would be loath to store it if I was trying to sell it too.
    Regards,

    Cade.

    2001 100 series Landcruiser
    190,000 Km and counting on B100, 280,000km total on car.
    Naturally aspirated, Walbro Pusher pump just upstream of tank switch valves, Cav filter with reversed fuel flow direction.
    At 160,000 km Rebuilt pump, Reconditioned head and manifolds, glow plugs. Injectors all good after 160,000 km on B100.

  8. #8
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    Re: Bio Sludge in fuel tank

    Yes in most cases it is glycerine, but not every case. This stuff was most certainly biological in nature (I had some sitting in the bottom of my Frantz and did some tests on it). Why it formed in my Triton but none of my other cars is a mystery to me. I know that this used to even be a problem in Dino - you used to be able to buy bacteriocide additives to add to your fuel to stop growth of algae. My solution to it is to not run B100, but to put at least 10% petrol in there - I reckon the aromatics would prevent bacterial growth. But it's not a problem for me anymore as I now run blended WVO mixtures

  9. #9
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    Re: Bio Sludge in fuel tank

    Quote Originally Posted by Captaincademan View Post
    One possible concern with long term storage of biodiesel is if its being stored its not being sold, so your return on investment is poor. I would be loath to store it if I was trying to sell it too.
    Always wondered about this, I never use my BD for at least 6 months and and as I only use it for starting, have some that is close to 2 years old and works fine. It is still oil, have some stored in glass bottles from each batch so I can get an idea of what happens to ti over time. Come of my bottles would be close to 15 years old and have a small line on the bottom of them of white stuff, but that's it and the bd looks great. Got some drums of bd under a stack of other drums which would be well over 10 years old and when it get to them will take some photo's and post what they look like, if they are still alright.

    The worst cases of junk I've ever had was when using blends over a decade ago, the hj61 sahara has had the most problems and it has been using WVO/BD for 6 years and seems to have finally settled down, but if I leave the tank half full for a few weeks when we are away, have found back stuff starts to come through and now always have my tanks full.

    One the other hand the hj60, which has been on wvo for well over 15 years and over 300000klms, can sit for months with half empty tank and it is fine. Still haven't touched the engine and it has done close to 700000klms, just keeps on going. Reckon the tank is lined with baked on vo, so there is no vo to metal reaction.

    Also found oil stored in metal drums goes off much faster then in plastic, after 6 months you can smell the rancid oil in metal drums, but in the plastic one, no smell.

  10. #10
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    Perth
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    Re: Bio Sludge in fuel tank

    Very interesting - I'd suggest that the BD goes off quicker in metal than plastic because it acts as a heterogenous catalyst.

    To add to my further comments, there are two differences between glycerine and the biomass I've observed. The first is the colour. Gly is dark brown (although it can appear black at a glance or if there is enough of it) whereas the biomass is jet, midnight black. The other difference is that the Gly won't go through my 1um Frantz filter but the biomass will. Also of course the gly is water soluble but the biomass isn't

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