Why does everyone use 22% Methanol?? - Diesel Forum

Nitro454 · 03-29-2006, 02:51 PM

So on my last two batches that were 40 gallons, I should have used almost 9 gallons of methanol. Well, I decided to go less. I used 5 and did everything else the exact same. Well, everything came out great and I nearly cut the metanol in half. I think we have been using too much and wasting it. I dont know if the quality of oil affects anything either. I have absolutely no water in mine and have been using a flat 3g/L of NaOH. No base of 5g/L at all. After everything is mixed in and had a chance to mix up, I will pull a small sample, mix it with alcohol, and throw in some indicator. If it comes out a light pink, i know it has fully reacted and I let it do its thing and go on as normal. I also tested this after I have completely washed and dried it, and no other glycerin settles out. Just something to think about for everyone out there. It has really cut down on cost and even makes washing easier since there is not as much excess methanol or lye in it.

RickHredf250 · 03-29-2006, 03:30 PM

Thats only 12.5%. I would be concerned about complete reaction and reaction time.
I use 22% all the time and have excellent results. Tried more but did not see any benefit. As long as the correct heat is obtained prior to conversion, I think 22% is the least I will ever go.
The addition of a methanol recovery system would, for me, would be a better way to lower my Cost Per Gallon.
Rick H...

waterdude · 03-29-2006, 04:46 PM

I've read that under ideal conditions (not possible in the real world), the biodiesel reaction would use 15% methanol by volume. 20% is the minumum recommendation with 22% as the best.

With your 12.5% methanol, you can expect leftover FFA's and lower biodiesel product. That proof would be to have your fuel tested for quality.

--Hugh

Huff · 03-30-2006, 05:00 AM

I use 20% with excellent results. (KOH)

cranetruck · 03-30-2006, 07:08 AM

I use about 20% methanol, but since I use it unwashed, the surplus methanol becomes part of the fuel and probably adds some heating value to it.
The mpg is almost identical to petro diesel so the methanol may have something to do with it.
My most recent mpg calculations are based on a trip to Florida and back using biodiesel one way and petro diesel for the return trip.
The mpg ranged from 8.5 to 9.5 for the approx 20,000 lb vehicle for either fuel.

grease_junky · 04-01-2006, 08:32 AM

methanol is your reactant and caustic is your catylist, by using less you may not be completly reacting,however by keeping processing temp. just under methanol vapor pressure and plenty circulating time,you may be o.k.. I like using alittle excess 20-22% to ensure complete reaction. [img]/ubbthreads/images/graemlins/cool.gif[/img]