Here is My thoughts...I have been acid treating a few batches but i seem to get so much water(about 15,000ppm or 1.5%) that i cannot get a complete base reaction even after three base stages. When the oil goes in it may have 1000-2000 PPM water which never gives me trouble when doing a regular base reaction. It becomes a problem after i acid treat it and produce water. Then if i can get a decent reaction after three stages i have produced between 5,000 and 15,000 ppm soap! Im guessing this is due to excessive sodium hydroxide and water.
So here is what i am thinking i am using a 500 gallon propane tank for acid treatment-so why not pull vacuum after 24 hours of treatment and have a reflux still on top and remove all the methanol, then once that is done go after the water. Now i should have good oil ready to go and i can add the methanol back in, but at least i got rid of all that water.
This is what i am planning on doing unless someone can tell me a better way to get soap levels down while getting a complete reaction. Thanks!!

Jason
-yes that would work, but it will take more time and energy. Going into ae with 3000 ppm of water IS a problem. spend the energy drying the wvo, pass the hot pan test as a min standard of dryness. Then when you go to the base stage, concider the methanol already in the mix as slightly contaminated, compinsate for this by adding 30% more for the base stage. use the enter batch of methoxid for a single base stage, settle, drain and repeat the base stage using 1gr koh in 1ml methanol/ ltr of oil in the reactor. Tom

Thanks fo rthe reply, I stated i usually have 1000-2000ppm water and you said 3000 WAS a problem well is 1,000-2,000? The oil looks great when it goes into the processer it looks like there is no water but there is some. I use the sandy brae water testing kit. My vacuum pump is on the way as soon as i get it hooked up i will dewater before acid treatment and see if that helps. will removing 2,000 ppm water before acid treatment lower the final reading after acid treatment by more than 2,000 ppm? because if it goes from 1.5% to 1.3% doesnt seem like it will help too much.

Also, i have noticed that after the first stage if i put in 1g/liter of sodium for the secand base stage that it makes a LOT of soap so i have been using more like .5g/liter. I also dont use the recommended 5 grams as a base. When i try that i end up with too much soap, then if i go back and add 1 gram for the secand stage i get 20,000-30,000 ppm soap and the biodiesel looks like gel. So i have been using the old number of 3.5+titration for first stage and .5 for secand stage. I still can never seem to get soap less than 5,000 until i demeth. Im not sure if this has anything to do with it but my processor has GREAT agitation. I do 140 gallons at a time and i have a mixer that turns around 300rpm + a centrifical pump rated at 70 gallons per minute going into a sparge tube that really rolls the mixture! usually mix for about 45 minutes each time. (Acid treat uses a different tank)

But my fuel does come out great after i get the soap out-it passed astm d6751-08

You did not indicate the initial amount of FFA, but from the water content I would say it is fairly high. Two thoughts. First look at the material after the acid step and see if it will separate on setting. If it does then the methanol layer will contain most of the water. If it does not separate you might start with a higher percentage of methanol. By physically separating and distilling the wet methanol a lot of energy and time is saved.
If you want to strip the methanol / water by heat and vaccuum then do not try to run thru a reflux column, just collect the material that comes off. You would need to heat to over 100 C even with a vaccuum.
After collecting enough wet methanol it could more efficiently be run thru a reflux column. This would allow you to recover excess methanol from both the acid and base runs.

Jason
-just a typo, i do lots of them the bottom line here, if you are doing ae treatment, make sure water content of wvo is 500ppm or less. you have the equipment to quantify the water amount, What is the T of your wvo. the higher the T the more water that can be made. Tom

I think your KOH titration would be over 38 ml KOH, or over 27ml NaOH. Just curious?

Titration was about 14 using sodium hydroxide. The layer seperates i use about 10% methanol and 2 grams sulfuric acid per liter/oil and the methanol/water still floats. Ending titration 3.8.

Why would you need to get the mixture to 100c with a vacuum to distill water/meth? Water will evaporate at like 60 degrees F at 10 torr which my pump says it is capable of. I've never used vacuum distillation before so if you have any insights that will save me time it would be appreciated!! I plan on using a propane tank and then pulling vacuum through a condenser and then a holding tank and then through the vacuum pump.

2000psdbio i have done a few vacuum removal of water on oil, first tried pulling vac on a 30 liter lpg tank then processor but not efficient. Then 100 liter lpg tank a bit better but still not good enough. My pump is 2 stage down to 75 micron the best results were directly off the processor through the vac pump once down to 29-30 hg then introduce very hot air in the bottom and watch plumes of mist from the vac pump. Problem is this could well shag my pump the oil goes milky white and must be changed and flushed immediately got it real dry but not worth the time or effort. good luck andy