I MIXED IN MY CHEMICALS AND LET MIX FOR 3-1/2 HRS. AFTER LETTING SETTLE FOR 10HRS I CAME TO THE CONCLUSION THAT THERE WASN'T A SEPARATION OF THE GLYCEROL. THE OIL WAS A DARK COLORED COMPARED TO TEA. COULD IT BE THE LACK OF KOH?
-seems like your conversion wasn't very good, did you try 3/27? I would try to repo a 1 ltr batch, to see how much koh it will take to push the reaction without adding too much caustic. Tom
" I don't know what I don't know until I know"
1994 GMC 6.5 Tubo 2005 Dodge ram 3500, 3 VW's 2000, 2002, 2005.
Tom is right to recommend a small batch to test the conversion because it sounds like you need to push it further. Do not try to convert the larger batch until you have some idea as to the failure.
There could be other causes at play here also. Was the oil dry? What temperature were you processing at? What was the titration of the feedstock? What amount of KOH did you use? How much methanol? How large a batch? Was the methoxide completely mixed? Did you follow a recipe from JTF?
Give us some more insight into your process.
I am not positive if the oil is dry or not. If the oil isn't dry could it cause the methoxide to neutralize and not react properly? The batch was 190gal, titration at 12 and used 38gal of methanol and 24.04lbs of KOH. Processed at 135 degrees. What is the best way to see how much water is in the feedstock? I have a plastic processor, so i am only able to get the temperature to around 145. Thank you for the help.
Water is our worst enemy, and it is everywhere so we need to minimize it whenever possible. Water will rob the catalyst (KOH) and use it to make soap leaving the reaction short. According to my recipe you were about 10 pounds of KOH short. I use 8 as a base plus titration.
Your oil is high titration, you need to investigate acid esterification to reduce the titration to a more manageable level. The methanol amount and process temp is right on. Methanol vaporizes at about 146.5 degrees, so 145 is a bit high.
To check your oil for water do the hot pan test. Heat a pan and add oil by the drop. If the oil sizzles and crackles it has moisture. You can also add a couple tablespoons of oil to a pan and heat it up. Watch for bubbles that will indicate moisture, if it just spreads out and remains bubble free, it is dry.
I believe this batch can be saved. You will get a lot of glycerine because of the high titration, look for maybe 75 to 80% conversion. If you get that titration down to 2 or 3 you will get close to 100% conversion.
That was my next procedure to do the hot pan test. Should the stove be set to medium teperature? And what do you mean by 75-80% conversion? And what is the procedure to reprocess this batch? Thank you so much for your help.
Don't bother with the hot pan test on this batch. There is no water, it is now converted to soap which you have to deal with in washing. The pan needs to be hot enough to turn water droplets to steam instantly (or almost).
You will reprocess by adding KOH and methanol to the batch, heating and mixing and then resettling. As Tom said before get a liter or two and see how much KOH it takes to get settling. That batch is far enough under reacted that you could do a titration and treat it like a regular batch of WVO. Keep in mind that there is already a lot of methanol already in the mix and you would only need about half of the normal amount. Also when figuring volume use the actual volume (WVO and methanol) not just the WVO you started with.
By 80% conversion, I mean that for every 100 gallons of WVO you will get about 80 of biodiesel. That is a very optomistic guess, your results will vary. When you use AE and get the titration down to 2 or 3 you will get 98 to 100 gallons fuel. That is what makes the extra steps worth it.
When you do the reproces, drain off a sample after mixing for an hour and let it settle off. It will drop the glycerin very quickly and you can do a 27/3 test to see if you have finished fuel or if it needs more time.
What is AE? That would be real nice if i can get at least 95% conversion. I will try the mixing again with 10% methanol and test for the KOH. Do you know if there's a different formula if using KOH compared to NaOH. Because im using the NaOH for my titration but actually adding KOH to the WVO.
Your making it hard for yourself titrating with NaOH and then processing with KOH-it would be much better to titrate with what you are processing with.
I only use NaOH at 5g per lt-I think the KOH guys use around 7g-8g per liter adjusted for purity.
AE is Acid Esterification. It is a process using sulfuric acid and methanol to lower the titration of the WVO. The process adds some time to the production, but the results are worth it.
Taralec is right on with his answer to the Na/KOH scenario. I recommend a new mixture of titration solution for every bag of catalyst. Titrate with what you react with, it takes two minutes and you waste a gram of catalyst.
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