I am new to making my own biodiesel but have made what i think are 2 successful 20gal batches. Someone please correct me if i am wrong. I have 20gal of oil and i add 4 gal of methanol. i add the appropriate amount of KOH per my tiration tests which are usually between 2-3. i use a base amount of 7g/L. I mix for 1 hr heating to 120F and then mix the methoxide for 45min. i let settle for at leat 24hours. i thought you were supposed to get only 10% glycerin which is about what i have been getting. i am draining out about 2.5 gal of glycerin. I run the rest through a purolite drywash filter and a regular fuel filter before going into the tank. I have been reading on the forums about you should get 80-95% yeild of your batch. Is that before or after you add the meth? Me having 20gal oil + 4 gal of meth = 24 gals of liquid. i drain out 2.5 gal glycerin = 21.5 biofuel? correct? Thanks for any feedback

 

What you are doing is not correct. First you should be using 4.4 gallons of meoh not 4. Also, 45 min mix at 120 isn't long enough especially if your using one of those little blue HF pumps. They are only pumping 5.5 gallons/min of water. If your set on mixing for only 45 min.,increase temp to 140-145 degrees. You are right that bio produces 10% glycerin but thats pure glycerin. The stuff you drain is glycerin, meoh, catalyst, soap,crud, and water. If you use 20-22% methoxide and your oil titrates at 2-3 you should be getting back 4.5 to 6.5 gallons of crude glycerin. If you got only 2.5 gallons back your bio is underconverted and should fail the 3/27 test.

 

thanks for the feedback. few more questions. the 4.5 to 6.5 gal of glycerin. that should be all the same black crud i was getting 2.5gal of. Could i not be getting a full reaction from not mixing enough or is that from not adding enough KOH to my methanol? Also i am thinking of switching to magnesol. i have heard a few statements about not mixing with a water pump. i was going to use a 1micron nominal bag filter and then a 1micron absolute spin-on filter. shouldn't that be good enough for the magnesol even if the pump grinds it any more than it allready is.

 

Right. If you were getting 2.5 of the black stuff before getting to the bio, you should be getting at least what you put in(4.4 gallons) and then some do to soap formation. You should be left with 18 or 19 gallons of unwashed bio. If you end up with more "bio" than oil you started with, that extra would disappear as soon as you washed it because its just unused methanol. You still haven't said what pump your using but 7 gram KOH plus a titration of 3 would be 10 grams per liter. 10 grams times 75.7 liters(20 gallons) is 757 grams or 1.67 pounds dissolved in 4.4 gallons of Methanol. If you are using a poly reactor I would bump up the temp to 130 degrees and leave the pump on for 1.5 to 2 hours. Let settle for 2 hours after pump shut-off and drain glycerine and then come back the next morning and drain the last little bit. See if that helps. Also make sure your oil doesn't have a ton of water in it.

 

Sorry, I am using a harbor frieght 320GPH water pump. There is a cyclonic mixer in-line one of my pipes to help with mixing. is it ok to turn on the heater(in-line,water heater element) after the methanol has been added? i don't want to blow anything up. Also does not getting the full amount of sludge mean i am not getting a good reaction or is extra methanol ok and i just need to wash it out. any comments on magnesol? also my oil pretty clean. the bar puts it right back in the container it came in so it doesn't sit outside in one of those containers. thanks

 

If you are using the HF pump you need to mix longer. I don't use heaters in reactors, some do. You will have plenty of heat if you get the oil up to 130-140. Not getting the full amount of glycerin is an incomplete reaction. A bunch of extra meoh means it should have bonded with an ester and didn't. I don't dry wash, I use water so I can't help you on that one.
Just so you know, I use a 40 gallon poly reactor with a Fill-rite 700 as a mix pump and four 250 gallon steel reactors with 80 gallon a minute mixing pumps. Oil is heated outside of the reactor. The poly tank gets oil at 140 degrees and the steel ones get the oil at 150 degrees. Pics at my webshots page.