After some research and encouragement, I changed from NaOH to KOH. All I have made so far are lab scale batches until I get the process down. I have calculated the difference for the KOH (X1.4%), done the titration with the KOH/distilled water, blended this with the 99% methanol and done the reaction. The result was unnoticeable at first. The "bio" layer and the glycerine layer are so close in color that they are almost indistinguishable. I have tried varying levels of KOH. The most straw colored bio I received was about a 20% conversion before the product turned dark. I have tried the same WVO with the red devil lye and received the same result. In the past, I had great success with the NaOH, but the oil was not used nearly as much. My supplier is a MDs in the area and the titration yielded 9.5g/L!!! Is there an intermediate step possible to neutralize the FFA's before attempting the conversion, so I may be able to distinguish between product and byproduct?

Thank you in advance,

Ben

 

[QUOTE=wbw189]After some research and encouragement, I changed from NaOH to KOH. All I have made so far are lab scale batches until I get the process down. I have calculated the difference for the KOH (X1.4%), done the titration with the KOH/distilled water, blended this with the 99% methanol and done the reaction. The result was unnoticeable at first. The "bio" layer and the glycerine layer are so close in color that they are almost indistinguishable. I have tried varying levels of KOH. The most straw colored bio I received was about a 20% conversion before the product turned dark. I have tried the same WVO with the red devil lye and received the same result. In the past, I had great success with the NaOH, but the oil was not used nearly as much. My supplier is a MDs in the area and the titration yielded 9.5g/L!!! Is there an intermediate step possible to neutralize the FFA's before attempting the conversion, so I may be able to distinguish between product and byproduct?

Thank you in advance,

There is a 2 step acid/base process to reduce FFA's but is difficult for home brew. Journey to Forever website discribes it, but it has been discredited. I had a similar problem when I first started. I found if I blend my high titration oils with my low titration oils it takes less KOH to make a complete reaction.

Since switching to KOH I'm using 13.44 grams/ liter, 3lbs-1344 grams per 100 liters/25gal oil. At a mix temp of 150 deg F mixed for 30 min it will start to seperate in 10-15 min.

FABMANDELUX.

 

Thanks, Fabman. I have been marginally successful in my "lab" with an appropriate amount of conversion (75%). My stir plate was set to 500 RPM and 55C. A cream colored product agitated in a sample container for just over 5 minutes and just as quick as you could snap your fingers, the product went dark brown. Is this similar to what you have seen?

I sure do appreciate your information.

Ben

 

Ben: Since I do not use an appleseed processer, but an open top mixer, I've watched the reaction closely. Before adding the methoxide the color is kind of honey colored. After adding the methoxide it changes to a "latte" color [lite tan], than quickly turns almost black. When it turns black it is the glycerol coming out of suspension. after running through the hydrocyclone it turns a real pale yellow. Is this what you are observing?

FABMANDELUX.

 

Yes, that is the same reaction happening, but my final product is not pale yellow. The product looks more like a dark ale. The only way I can tell the difference is to have a light source behind the flask I mixed it in and the bio is transparent. This made me wonder if I used the wrong amount of lye or if I missed a step.

Ben

 

Sounds like not enough KOH, A quick test for full conversion: put 800ml biodiesel in 1 ltr bottle, add 200ml methanol + Lye for 1 lt. Shake Well, 1-2min. Let it stand 30min. Watch for any glycerol to settle.

If your trying small batches, try adding 50 percent more Lye. If you get a good reaction you can adjust down from there.

The only other thing it could be is over-used oil. If the WVO is light colored than the bio will be light. If it is very dark the bio will be dark.

FABMANDELUX.