Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: The energy it takes to make biodiesel

  1. #1
    Join Date
    Mar 2013
    Location
    Sydney, NSW
    Posts
    195

    The energy it takes to make biodiesel

    Evening all,

    Here's an electricity load profile of my house today while I made a batch of bio from 180L of WVO.

    I try to get the whole operation as close to the middle of the day as I can while my 1.5 kW solar PV system is doing it's best.

    As you can see, the PV barely touches the sides when the 2.4 kW oil heater is on, but it covers a lot of the mixer, which I run for 90 minutes to do the reaction.

    I think it costs about $0.35/litre to make including KOH and methanol, without the solar contribution.

    Even though the PV system is relatively small, on average, I export 65% of the power it generates to the grid, even though I set my washing machine and dishwasher to go off either side of midday. Quite tough to utilise the full potential of your PV system without a battery.

    Click image for larger version. 

Name:	Load profile on biodiesel day.jpg 
Views:	38 
Size:	118.9 KB 
ID:	2253
    3DB
    1995 Holden (Isuzu) Rodeo 2.8TD 4X4 - B100 since April 2013
    1976 Mercedes 300D Turbo 'The Coal Grenade' - B100 since May 2016
    (@thirddegreeburns on Instagram)

  2. #2
    Join Date
    Sep 2005
    Location
    WA
    Posts
    4,095

    Re: The energy it takes to make biodiesel

    Reduce the heating and increase the mixing time. Some people make biodiesel at 30C and agitate (stirrer) for one hour to produce usable biodiesel.
    Life is a journey, with problems to solve, lessons to learn, but most of all, experiences to enjoy.

    Current Vehicles in stable:
    '85 Mercedes Benz W123 300CD Turbodiesel single tank using 95% used cooking oil and 5% to 10% misfuel (where someone had filled diesel vehicle with petrol).
    '06 Musso Sports Crew Cab. Running on used cooking oil with 5% to 10% misfuel.
    Toyota Camry Hybrid - (Wife's Car)

    Previous Vehicles:
    '90 Mazda Capella. (2000 - 2003) My first Fatmobile. Converted to fun on veggie oil with a 2 tank setup. Died when supercharger stuck at max boost for weeks. Stretched head bolts.
    '80 Mercedes 300D. 2 tank conversion [Sold]
    '84 Mercedes 300D. 1 tank, no conversion. Replaced engine with rebuilt OM617A turbodiesel engine. Finally had good power. Donor for current Fatmobile coupe. (body parted out and carcass sold for scrap.)
    '99 Mercedes W202 C250 Turbodiesel (my darling Wife's car)[sold]
    '98 Mercedes W202 C250 Turbodiesel (my car)[sold]
    Parts Car C220 1993 All body panels, headlights, interior engine and ECU available.


    Searching the Biofuels Forum using Google
    Adding images and/or documents to your posts


  3. #3
    Join Date
    Dec 2016
    Location
    York UK
    Posts
    86

    Re: The energy it takes to make biodiesel

    3DB, your cost is massive, it equates to 20pence/litre in our money. Last time I worked this out for me it came to well under 10ppl (something like 8.5 from memory)

  4. #4
    Join Date
    Jan 2006
    Location
    ลึก ประเทศอินเด&
    Posts
    1,940

    Re: The energy it takes to make biodiesel

    Hi 3DB,
    It looks like you are using a 2.4kw heater and heat for about 2 hours.
    Where I live general use home electricity is about 26 per kwh.
    That works out to a total cost of about $1.25 to heat the whole batch of oil.
    About 0.7 per litre

    Your graph also clearly shows why you should only boil water once
    Last edited by tillyfromparadise; 22nd September 2017 at 09:23 AM.

  5. #5
    Join Date
    Mar 2013
    Location
    Sydney, NSW
    Posts
    195

    Re: The energy it takes to make biodiesel

    Hi all,

    Here is some detail around my cost calculation. It came out to $0.34/litre of finished fuel. This includes chemicals and electricity for all heaters and pumps (net after solar contribution). My starting 180L of WVO is free.

    If I added my time to the calculation, it would be more like $34/litre! As I always say, it is a labour of love rather than a money-saving exercise.

    Tony - I have reduced my start temp from 60C to 50C already to avoid excessive vaporisation of methanol. I mix for 90 min at present - do you think that is an overkill? I am keen to try 30C next batch.

    Cheers,
    Click image for larger version. 

Name:	Biodiesel cost calculation.jpg 
Views:	8 
Size:	80.4 KB 
ID:	2254
    3DB
    1995 Holden (Isuzu) Rodeo 2.8TD 4X4 - B100 since April 2013
    1976 Mercedes 300D Turbo 'The Coal Grenade' - B100 since May 2016
    (@thirddegreeburns on Instagram)

  6. #6
    Join Date
    Dec 2016
    Location
    York UK
    Posts
    86

    Re: The energy it takes to make biodiesel

    My largest saving when processing is on chemicals. My glycerol pre-treated oil shows a conversion of aroung 20% to start with, so at the moment I am only using around 11.5% added methanol plus a small amount contained in the ASM for full conversion.

    Here are my costings for a 200 litre batch;

    Total electricity used (including that to power my 1/2HP compressor to mix up glyc/oil in the prewash tank) 12KWH @ 14p/KWH 1.60
    (I also do stage 1 conversion at ambient)

    Methanol used 23 litres @ 39 pence/litre. 8.40

    650gms KOH 1.20

    1.2 litres ASM @ 2.00/litre = 2.40

    In total this gives 13.60 which equates to 6.8pence/litre 0.116 Aus Dollars?

  7. #7
    Join Date
    Jan 2006
    Location
    ลึก ประเทศอินเด&
    Posts
    1,940

    Re: The energy it takes to make biodiesel

    Hi everyone,

    Quote Originally Posted by smithy View Post
    My largest saving when processing is on chemicals. My glycerol pre-treated oil shows a conversion of aroung 20% to start with, so at the moment I am only using around 11.5% added methanol plus a small amount contained in the ASM for full conversion.
    Because smithy is relatively new to this forum it is best to explain what smithy means here.
    Apparently people give smithy their drained glycerol that contains large quantities of methanol and KOH which he uses to perform a first stage reaction which he does not call the first stage reaction but instead calls a glycerol pre-treatment. Apparently smithy heats this first stage reaction.

    He then performs a second stage reaction which he calls the first stage reaction that requires he add a further 11%- 12% methanol that he has purchased to achieve a complete reaction. Evidently he does not heat the second stage reaction.
    It is frequently quite confusing to understand what smithy means because he uses different terminology than most people and sometimes omits telling people some of the production steps he performs. You are often not quite sure what he means.

    If people were not giving smithy all their methanol rich glycerol to perform his first stage reaction with, he would have a further expense to supply this methanol other people are apparently giving him.
    Last edited by tillyfromparadise; 23rd September 2017 at 12:53 AM.

  8. #8
    Join Date
    Dec 2016
    Location
    York UK
    Posts
    86

    Re: The energy it takes to make biodiesel

    Maybe you should try a glyc wash Tilly, to reduce your costs. BTW my glyc wash is also done at ambient temp.

  9. #9
    Join Date
    Jan 2006
    Location
    ลึก ประเทศอินเด&
    Posts
    1,940

    Re: The energy it takes to make biodiesel

    Hi smithy,

    Quote Originally Posted by smithy View Post
    Maybe you should try a glyc wash Tilly, to reduce your costs.
    People do not give me their methanol rich glycerol to perform a first stage reaction with.
    In any event I only use 14% methanol in a single stage reaction and see no benefit in doing a 2 stage method.



    BTW my glyc wash is also done at ambient temp.
    Have you changed your mind again ??
    On the infopop forum when I told a person he could do the first stage glycerine reaction without heating you objected saying:
    "This doesn't work too well. As the reaction is what is known as an equilibrium reaction and even though there are excess chemicals in the glycerol, the reaction is too slow to proceed with any degree of practicality at ambient."

    I have noticed that you frequently contradict something you have said in the past to disagree with something I have posted.
    So are you now again doing both stages of your reaction for 45 minutes at room temperature

  10. #10
    Join Date
    Jan 2006
    Location
    ลึก ประเทศอินเด&
    Posts
    1,940

    Re: The energy it takes to make biodiesel

    Hi 3DB

    Quote Originally Posted by 3DB View Post
    Tony - I have reduced my start temp from 60C to 50C already to avoid excessive vaporisation of methanol. I mix for 90 min at present - do you think that is an overkill? I am keen to try 30C next batch.
    The actual time it takes for the reaction to reach completion depends on a number of things including, but not limited to, the amount of chemicals used, the temperature of the reaction and mixing vigor of the reactor.
    Some reactors are never able to achieve a complete reaction in a single stage and some are very quick.

    You will need to do some testing to see how long it takes for your reactor to do a complete reaction.
    I assume you want to make biodiesel that passes the 3/27 test and your reactor is currently making biodiesel that passes the 3/27 test in a 90 minute reaction at 60C.
    You have now reduced the temperature to 50c and want to know how long it will take for your reactor to reach completion at this temperature.

    This is what I would do in that situation.
    Using the new reduced temperature, process a normal size batch of oil keeping all chemical quantities and production procedures normal except the new reduced temperature.
    Every 10- 15 minutes remove a small sample from the reactor and allow it to sit for 5- 10 minutes which will allow some of the glycerine to settle out.
    Then perform a 3/27 test from the sample taken.
    Keep the reactor running until you have a pass on the 3/27 test.

    While it is true there will be a small amount of methanol and glycerine remaining in the test biodiesel, this will give you a very good indication how your reaction is progressing and how long it will take for your reactor to achieve a complete reaction.

    Please let us know what you find out.
    Last edited by tillyfromparadise; 26th September 2017 at 04:48 PM.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •