Glycerine or whey in digester?

Discussion in 'Renewable Energy' started by Chippy, Apr 12, 2018.

  1. Chippy

    Chippy Member

    Location:
    Cumbria
    Crust appeared because whisk isn’t up to the job but we’re looking at options of putting another stirrer in or gas mixing. Another stirrer around 5k or gas mixer around 10k.
     
    thesilentone likes this.
  2. thesilentone

    thesilentone Member

    Given your experience so far, I would look very carefully at the alternative agitator and see one before installing (if from the original supplier) Landia;s system does work, however the hype is built on the back of installing them in early German AD Plants that were not operating above 70% efficiency. In addition, you really have to look at parasitic loading for both systems.
     
  3. Chippy

    Chippy Member

    Location:
    Cumbria
    We’re considering doing our own version of landias but without the gas bit. Have a 22kw external pump sucking out of the store at the bottom and blowing it back in near the top. That would cost between 5-7k I think
     
  4. Chippy

    Chippy Member

    Location:
    Cumbria
    If I got an artic of whey, and used it over a 4 week period let’s say, would the last few weeks of whey have little effect on methane because it will have lost it all in the tank it will be sat in?
     
    Last edited: Apr 15, 2018
  5. sjt01

    sjt01 Member

    Location:
    North Norfolk
    My wife, the cheesemaker, says it will be quite acidic and have used all the sugars, so should be OK. Might get quite smelly though.
     
  6. thesilentone

    thesilentone Member

    It is important these small scale systems work as the potential in the UK is good. However, from what I am reading and given the simplicity of the system, you appear to be having lots if issues.

    Mono-digestion has biological challenges, however the enzymes being developed should benefit the system stability risks.

    Is your supplier supporting you ?
     
  7. Chippy

    Chippy Member

    Location:
    Cumbria
    No support now, Biolectric weren’t supporting the UK supplier so UK supplier had to give up before he bankrupt himself
     
    thesilentone likes this.
  8. thesilentone

    thesilentone Member

    Sadly, I had a feeling this might happen, it is not the first time.

    Try contacting them directly, and keep your efforts in the public domain.......

    United Kingdom & Ireland

    Laurens De Vos
    laurens.devos@biolectric.be
    +32 499 36 60 22

    https://www.biolectric.be/en/contact/
     
  9. Chippy

    Chippy Member

    Location:
    Cumbria
    Already in contact with him. I just hope he’s helping as much as he can
     
  10. maen

    maen Member

    Location:
    S West
    I would go back to basics.
    1.Temp
    2. Why do I have a floating layer
    - bedding in slurry?
    - pre separation might be cheaper
    3. Could I drop the level to aid the existing stirrer. Raise level gradually once floating layer disappeared.

    The problem can be solved. Small steps.
     
  11. thesilentone

    thesilentone Member


    Great advice, small steps.

    However dropping the liquid level substantially is maybe the biggest cause of explosion with a Biogas Plant (forced induction of air) so take great care if this route is followed.

    If pre-separation is added, what will he use for feed-stock ? (VS)
     
  12. maen

    maen Member

    Location:
    S West
    Small steps.

    To include dropping level by centimetres at a time until stirrer working better. Over time.

    If the floating level is cow bedding or waste silage in slurry this can be kept separate as it appears that it causes the system problems. Bearing in mind the European system may have been perfected on slurry from totally slatted dairy floors.
     
  13. Chippy

    Chippy Member

    Location:
    Cumbria
    Already dropped level 200cm and hasn’t had any effect. Problem with dropping level is I’m taking liquid out so makes it harder to stir. I was bedding with paper and now I’m on sawdust. I would like to use a bedding that aids gas production but can’t get hold of oat husks and Im not aware of anything else
     
  14. thesilentone

    thesilentone Member

    How do you take out cow bedding and waste silage only, without being left with a liquor at around 2.5% DM ?
     
  15. thesilentone

    thesilentone Member

    Chippy,

    What is the dia of your digester and mixer configuration ?
     
  16. The Son

    The Son Member

    Location:
    Herefordshire
    What did your temp drop to?

    I lost nearly 8 degrees in the last cold spell as we heat our chicken sheds and I took too much heat out of the tank, has taken nearly 5 weeks to get it back.

    My advise on mixing, simple is best, I have three mixers in my tank, two moveable submersables, and one paddle giant. One of the submersables has broken and I now have an expensive operation retreiving and replacing it, roof off and two cranes

    The paddle giant is a metal paddle, set in the tank on a massive nylon bearing, with the motor on the outside, so any maintenance can be done easily, if I had my time again l would just but two of these in.

    In my opinion gas mixing is an expensive gimmick, adding cost and complication, for no benefit.

    I do agree with all the other comments though, get some consistency in your feeding first before you do anything.

    Are you taking regular biological samples?
     
  17. sjt01

    sjt01 Member

    Location:
    North Norfolk
    Gas mixing has worked well for us for 9 years, minimal maintenance and all outside the tank. Nothing could be much simpler, low power motors. Changed the vanes on one compressor, more as a precaution, after over 27,000 hours.
     
  18. Chippy

    Chippy Member

    Location:
    Cumbria
    Diameter is 15 meters. Mixer is just a 5kw whisk.
     
  19. Chippy

    Chippy Member

    Location:
    Cumbria
    About to take another sample tomorrow to see what’s changing. My slurry certainly changed. Its in going speed gone from 100m3/hour to 18
     
  20. Chippy

    Chippy Member

    Location:
    Cumbria
    Temp has dropped from 37 to 27
     

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