Correct amount of KOH and NaOH

[Hoops]

Hi, This is my first post I have been reading quite a bit since I found this site. I have made a few test batchs and a a few 100 litre batchs with mixed results.
I keep finding confilting data for the base amounts of KOH and NaOH (before titration), can some one please let me know the corect amounts.
Thanks
Hoops

[tillyfromparadise]

Re: Correct amount of KOH and NaOH

Hello Hoops

The Chemist "Neutral" performed some GC tests with new oil that showed it requires 5g NaOH/7g KOH per litre to "Just Scrape in" to ASTM conversion.

The "latest" thinking is 5g NaOH + (Titration X 1.2) should "Just Scrape in" to ASTM conversion if you are using 200ml methanol.
Increasing the 5 to 6 should increase conversion

[Red Angus]

Re: Correct amount of KOH and NaOH

Hello Hoops

The Chemist "Neutral" performed some GC tests with new oil that showed it requires 5g NaOH/7g KOH per litre to "Just Scrape in" to ASTM conversion.

The "latest" thinking is 5g NaOH + (Titration X 1.2) should "Just Scrape in" to ASTM conversion if you are using 200ml methanol.
Increasing the 5 to 6 should increase conversion

Tilly,thanks for your reply about the correct base amount of KOH. I am going to try this tonight instead of the base amount of 4.5 I had before from the JTF site. Iwas told to heat veg oil to about 40C then add 20% methanol/KOH mix and gently mix for 20 minutes. Do you think that is enough time? Also, I was told to leave bio settle for about 1 week before use. I think I read somewhere you said glycerin can take 3 to 4 weeks to settle.....? I just changed my cartridge fuel filter and main fuel filter in Nissan 4.2T after 1900kms 60%bio/40% bought diesel. Main canister had some glycerin looking liquid in it. Could that be a problem? And would 3 to 4 weeks settling time get rid of this? By the way, I have found your tips/suggestions on this site to be invaluable...so thanks.

[Maddog]

Re: Correct amount of KOH and NaOH

To Red
We are using 7g as our base + titration and we heat the oil to 40degrees and then process for 90 minutes. We then add 5% water and mix for another 15 minutes. We leave the mix over night and let the glycerol to settle with the water mixed in the glcerol. This can then be washed several times and then let to dry for a week . All soap and glycerol settles to the bottom and you can then decanter off. We also started with a 4.5 base and had several batches turn to glop. Instead of washing several times you can bubble the batches for several hours.
Good Luck

[joe]

Re: Correct amount of KOH and NaOH

Red Angus, you might want to do a search here at this website on the JTF website. The has been "some discussion" on the credibility of the site recently that may not get rehashed.

Also I thought the base amount being peddled be the JTF was 3.5 and not 4.5. Has that changed? Ahhhhhh. I've just read we are talking in differing lingo. Tilly is talking about NaOH and Red Angus is talking about KOH. (a Trap for new players). In short now its accepted for 5 grams for NaOH and 7 grams for KOH. Get this right and then make any experimental variations.

The recommended temperature (and this is well documented) is 50 degrees and at this temperature the conversion should take about 45-60 minutes (closer to 45 but better off going longer than shorter.)

Red if you are only mixing for 20 minutes that will not be a complete reaction at this temperature. Also you will be wasting your meth and KOH as it will settle into the glycerine and not be used.

If you are not going to wash. Allow at least 24 hours and even up to one week for your glycerine to settle. The soap will take up to 4 weeks to settle. You can assist this process by "dry bubbling". Put your air bubbler into the bio (after seperation from the glycerine) and bubble for 48 hours. I've not tried this but it can help glycerine and soap to settle, and will help to dry the bio of the methanol. After the 48 hour period remove and soap from the top and any "stuff" from the bottom.

Maddog batches turning to glop can be from water or incomplete reaction. Like you said if you are using 4.5 base plus t then you may not be getting the reaction started. (but yopu prolly know this by now)

[tillyfromparadise]

Re: Correct amount of KOH and NaOH

[Hello Red Angus

I am glad my information has been of value to you.
I recommend very violent mixing to start, the more violent the better.
Once the oil increases in viscosity and then suddenly decreases in viscosity, you do not need to mix so violently.
With good strong violent aggitation this occures within a minute or less with a 50 litre batch.

As has been stated, the reaction takes about 1 hour at 50deg C.
For every 10deg C the reaction Temperature decreases the time doubles.
At 40deg C it will take about 2 hours for the reaction to finish.

Methanol in the biodiesel will hold some soap in solution.
Washing with water will remove methanol, glycerine and soap.
If you do not wash and this methanol evaporates, the soap will settle out.
If you bubble the biodiesel for a day or 2 in the sun and then allow it to sit virtually all the remaining soap/Glycerine will settle out.
If you then do a "Shake-um up" test with this biodiesel with soft water the water will seperate very clear which indicates no soap or glycerine is left. After bubbling I would not use the biodiesel until the biodiesel is crystal clear after at both the warmest and coldest temperature you experience.
You will also need to run it through a filter before using it.

If you do not bubble the methanol out, I would allow the biodiesel to sit for 4 weeks

If you are getting glycerine in your filter you still have glycerine in your fuel.

Tilly

[scooby]

Re: Correct amount of KOH and NaOH

i have found that a base of 3.5grams per liter works well but u gotta do yr tritation properly it will very with t eh amount of fat u ahve in yr oil
but if u strian in thru justa cloth which this can take sometime it will remove most of the fat i find that in 80ltrs i only use about 32grams all up in my fuel

[joe]

Re: Correct amount of KOH and NaOH

i have found that a base of 3.5grams per liter works well but u gotta do yr tritation properly it will very with t eh amount of fat u ahve in yr oil
but if u strian in thru justa cloth which this can take sometime it will remove most of the fat i find that in 80ltrs i only use about 32grams all up in my fuel

5 grams will work better. You use 32 grams for 80litres?? Are you sure this isn't 320 grams? If you have to filter the unconverted fat then you just aren't processing correctly. What is your aim here to save on your ingredients or to make quality fuel?

[dagwill]

Re: Correct amount of KOH and NaOH

i have been v slack on the titration step. instead i do 3 or 4 small batches at once [1 ltr each ] in the cut off soda bottle.
One with 3.5 one with 4 one with 4.5 and 5 grms of Naoh
I then use the lowest amount that works, useually 4.5 grms total Naoh/ltr of used canola oil.
question.. Is getting the right amount of Naoh chemicaly important,, are we trying to use the bare minimum so theres no waste,,Or would i be just as well to say 4.5 useually works for me ,stuff it ill just add5.5 or 6 as the exsess will simply drop out with the glycerine. or will this excess lead to nasty soaps that would not be there if i were a bit more carefull

[tillyfromparadise]

Re: Correct amount of KOH and NaOH

Hello Dagwill

Testing has shown that if You want to make ASTM Conversion biodiesel (98% +) then you need to use at least 5g NaOH + titration mixed into 200ml methanol.
Most indirect injection Diesels do not require ASTM conversion biodiesel.
Newer Direct injection engins are still a question Mark as to what they require.
The more NaOH you use, the higher the conversion and the more soap you will produce.

It just depends on what you want to use in your car.

As "Neutral" has often said "Seperation is not an indication of High Conversion biodiesel"

[Hoops]

Re: Correct amount of KOH and NaOH

Hi thanks for the reply, Sorry its taken so long as I have had a PC meltdown.
That clears things up a bit.
Hoop's

[joe]

Re: Correct amount of KOH and NaOH

As three-time soap box derby champion Ronny Beck says "let gravity be my friend".

Dunno.

[scooby]

Re: Correct amount of KOH and NaOH

5 grams will work better. You use 32 grams for 80litres?? Are you sure this isn't 320 grams? If you have to filter the unconverted fat then you just aren't processing correctly. What is your aim here to save on your ingredients or to make quality fuel?

well i strain it thru cloth to take excess fat out of the oil it makes a better fuel and u dont have to use so much NAOH and i start with a base of 3.5 grams per litre and then when i do tritation i add that to it
for every 1ml of 0.1% naoh solution u need to nutralise it it works out to 1g of NAOH added to a litre of oil
EG: if u get a tritation of 1.5ml then it becomes 1.5g + the 3.5g per litre in a 100ltr batch this would equate to 5g times 100 thats 500g of NAOH to do the batch and ya dont often have to much trouble nutralising the wash process when it has been finished

[scooby]

Re: Correct amount of KOH and NaOH

5 grams will work better. You use 32 grams for 80litres?? Are you sure this isn't 320 grams? If you have to filter the unconverted fat then you just aren't processing correctly. What is your aim here to save on your ingredients or to make quality fuel?

yes sorry wa s supposed to be 320g and most of my batches turn out that way when using the cloth to strain it out i have had to use 380g for a few rare ones tho

[Tony From West Oz]

Re: Correct amount of KOH and NaOH

well i strain it thru cloth to take excess fat out of the oil it makes a better fuel and u dont have to use so much NAOH and i start with a base of 3.5 grams per litre and then when i do tritation i add that to it

The high melting point oils (you call them fats) are unlikely to be the cause of a high titration. What you should do to verify this, is to titrate a sample of the oil before removing the high melting point oils, another after filtering them out and another sample of the high melting point oils. I doubt that you will be able to differentiate between the titration values for each sample.

for every 1ml of 0.1% naoh solution u need to nutralise it it works out to 1g of NAOH added to a litre of oil
EG: if u get a tritation of 1.5ml then it becomes 1.5g + the 3.5g per litre in a 100ltr batch this would equate to 5g times 100 thats 500g of NAOH to do the batch and ya dont often have to much trouble nutralising the wash process when it has been finished

Yes, but you should be using a catalyst portion of 5.0 g/Litre, not 3.5 g/Litre, this would give a total Caustic of 6.5 g/Litre, for optimal conversion, using 20 - 25% Methanol.
Using 3.5 as the catalyst amount is likely to give you low conversion fuel and frequent problems with washing and emulsions.
Tony