QUESTION, 1 STAGE PRODUCTION LOOKS GOOD, GLYCERIN SEPARATES OUT, THEN I POUR OUT GOOD BIODIESEL AND WASH 3 TO FOUR TIMES, , THE PROBLEM: OIL SEEMS HAZZY ALTHOUGH WATER LOOKS CLEAR, I WASH SEVERAL TIMES LET STAND FOR 24 HOURS BUT STILL HAZZY, WHAT CAN THIS BE? I LIVE IN A HUMID ENVIRONMENT, CAN INITIAL OIL HAVE TO MUCH WATER IN IT? HOW CAN I CLEAR THE 2 ND STAGE BIODIESEL?
I am not an expert. I would say dry wash using magnesium silicate after bubble drying warm biodiesel. I guess the cloudiness is caused by water clinging to mono and diglycerides. Drying the biodiesel, then dry washing should remove most of it I expect. Oil might have been wet, methanol might have been wet, Sodium hydroxide might have been old or degraded, might have not used enough caustic catalyst. Might not have reacted long enough at high enough temperature. Might have not used enough methanol even if it was dry methanol. Might not have mixed adequately during reaction. If you are really in need of help, how did you make it? I only make very small batches, but I might be able to help. Thanks
hey wesley, thanks for your reply,
This is what I did, I first filtered used cooking oil, then i transfered to a container in which I did a 1 liter batch, and heated it to 50-55C. I noticed that when i did my titration, the oil, methanol, sodium hydroxide solution, phenol drops, did not completely disolve, seems to form water droplets and really never titrated to a dark pink solution. Also noticed, that metoxide and sod. Hydroxide dissolved but never really heated up to much, maybe 30-35 c, maybe methanol and sodium . hydroxide did degrade. Then i added the metoxide to the hot oil and mixed for 10 min. i noticed the color change (lighter) and then in 2 hours noticed the seperation of glycerin (bottom) and almost clear oil on top. Then i took oil on top transfered to beaker, added warm water, and washed and drained it about 4 times. Oil still looks Hazzy. Today, i took that washed oil and heated to 100c for 20 min. oil finally cleared up. However, did the 27/3 test and noticed a hazzy solution on top with a brown circular oil droplet the size of two dimes in the bottom, does this indicate insufficient sodium hydroxide? However , after heating, the biodiesel is finally clear, although the bottom has a few particles at the bottom. thaks for your help, ill wait for feedback!
I think that is a fail on the 3/27 test. It is all supposed to dissolve in dry methanol. I think it is under reacted. Did you use 20 percent or more anhydrous methanol for your reaction? What is the purity of your sodium hydroxide? What was the titration number? How much sodium hydroxide did you use in the first reaction? How big a batch are you making? Is it just 1 litre? I read on journey to forever website that someone decided 60 degrees centigrade was the best temperature for a methanol/caustic/ vegetable oil transesterification reaction. If you're just making one litre that's more my quantity rather than hundreds of litres. The batch I'm working on now is 1/2 litre, using new corn oil, commercial grade anhydrous ethanol, and potassium hydroxide. The volume of two dimes fallout in a 3/27 test is a lot.
way under reacted. Definitely go to Rick's website.
make sure it passes 27/3!!
you don't list where you live, but I have in the Southern US..yes its humid..doesn't change passing 27/3.
also..POST WITHOUT CAPS ON!!! WHY ARE YOU YELLING???
is clear you haven't done enough reading on this site..
start read each section..until you get to page 10 of each section.
you can skip the acid unless you have oil that titrates more the 5KOH..
then read the that section..yes ALL THE POSTS..not just the first 10 pages in a thread either.
yea..some think its called homework..so..read it..I did when I was learning..every DAY!!
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