KOH vs NaOH

[chenhongxia]

It seems that it's pretty much impossible to screw up a batch of biodiesel when you use KOH. I've made many small batches using NaOH - but my oil titrated pretty high and NaOH didn't seem to be able to handle it well. I had many failed 2 liter batches. I've been playing around with the recipe with KOH and tried reducing the amount of methanol per the recommendation of another biodieseler on this site .It was a good suggestion, as I dropped about a gallon of methanol out of the mix and didn't have any real repercussions. My initial yield was a little lower, but we'll see what happens. I've found that by placing my glycerin into a barrel and letting it continue working, I can often salvage some additional usable biodiesel out of it. A 40 gallon barrel of glycerin yielded about 15 gallons of biodiesel after ~6 months .

The reduced methanol recipe brings the cost down a bit. I've located a source for KOH locally and picked up 100 lbs of the stuff. That drops the shipping costs out of the price. 40 gallons of biodiesel took just under 8 gallons of methanol ($6.19/gallon) and 4.83 lbs of KOH ($1.78/lb) cost $58.11 to make ($1.45/gallon). That sure beats the $4.69/gallon for diesel at the pump locally!!! That's about a $90/tank savings. It's not as cheap as WVO, but it works pretty well for the short trip drives that my wife usually does - and it's cheaper (and safer!) than most blends.

Edited December 2, 2008 by Phi for All
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