Re: The energy it takes to make biodiesel

Reduce the heating and increase the mixing time. Some people make biodiesel at 30°C and agitate (stirrer) for one hour to produce usable biodiesel.

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)

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

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,

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?

Re: The energy it takes to make biodiesel

Hi everyone,

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.

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.

Re: The energy it takes to make biodiesel

Hi smithy,

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.



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

Re: The energy it takes to make biodiesel

Hi 3DB

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.

Re: The energy it takes to make biodiesel

Sounds like a good methodology, Tilly. Will do next batch.

Re: The energy it takes to make biodiesel

Hey Tilly,

Now that you have said it seems obvious. Cant believe I didn't think of such a simple thing before. 'face palm'.

I am upgrading to a more expensive car, and would like to investigate improvements to my process. the idea of monitoring the batch as it brews is a pearler.

Thankyou mate!

Re: The energy it takes to make biodiesel

I know there are quite a few electrical savvy people on this forum, so this is not aimed at those, but the rest of us knock about fixer-uppers. In QLD, im not sure about the other states, you can put up to 5.0Kw or thereabouts per phase down the line from solar production. Therefore if you have 3 phase at your house, you can upgrade to a 15.0kw system....

now this does require that you can access the additional funds, have lots of roof space for a big system and very little shading.

I recently fitted a 14kw system to my roof (52 solar panels with micro inverters) with what at the time was going to be a 5 year return on investment. I have just changed to Alita (or whatever its called) from red energy and have basically cut the ROI time in half. I now get 11.0c feed in tarrif as opposed to the 6.0c tarrif before and a big 25% discount for pay on time (which is easy because the bill is tiny) on I think 19 c/kwh as opposed to 26c /kwh.

Aircon can crank along all summer now. Very happy. I didnt know I could get such a big system until I chanced on a solar company that does large commercial installs. all the little operators that popped to service the domestic market just wanted to sell me a 5.0kw system.

Now I know this is a bit off topic, but it does lend a thought to the affordability of running bigger heaters to improve processes.

Re: The energy it takes to make biodiesel

I did all the calcs years back on how much heat for how much oil for how long, I do know 1 joule per ml per degree C for water, just getthe specific heat of oil which is about 0.7 something and do some calcs.

Cade put in a 3 phase socket, and choose the heater element you want, 3 of, one per phase and go for it. If you really want I will put in a temp control,. automate the pump etc?Mine has a PID to get to 56, turnon the stirrer and I do some manual things, lots of work for ease of use!

Re: The energy it takes to make biodiesel

Cade - a 14kW domestic PV systems massive! You could probably put your washing machine, dishwasher, the AC and heat a batch of oil around midday and still be exporting to the grid. Good on you for offsetting the carbon emissions of many of your neighbours.

You will be well and truly set when the price of batteries gets to a reasonable level.

I would like to have more on my place, but it will be a struggle to fit much else. As it is, if I had batteries I would be self-sufficient 90% of the time, even with my little 1.5 kW system as we rarely use more than 4 kWh/day.