This is an edited crosspost of a couple of messages about this that I posted on
the St.
Louis Biofuels Club list.

Anyone who starts making biodiesel needs to have a plan for proper handling,
storage,
and disposal of the glycerol byproduct.

Be sure to refer to the glycerol MSDS, which has a great deal more information
than what I
am going to tell you based on my experience.

Every time you make a batch of biodiesel, you will also make about as much
glycerol as
the amount of methanol you use. In my case, I use 22% methanol so I would expect
to get
at least 22 gallons of glycerol for every 100 gallons of biodiesel I make. In
reality, I
actually get more like 25 gallons per 100 gallons of fuel because I often use
the 80:20
method which results in higher conversion and therefore more glycerol.

Let's talk first about handling and storage. Glycerol is a vegetable form of
alcohol, and all
by itself is quite flammable. However, when you separate it from biodiesel it
also contains
about 30% methanol by volume, so that makes it toxic and even more flammable.

When you handle glycerol, you should use all the same precautions you use when
handling methanol. For personal protection, you should work in long sleeves and
pants,
gloves, and closed shoes or boots so you do not get it on your skin. You should
wear
splash goggles and/or a face mask even if you wear glasses. Your system should
include
a way to transfer glycerol between containers without exposing you to fumes.

If you plan to store glycerol you should use the same guidelines as for methanol
storage.
For small amounts, store it inside a metal flammables cabinet. If you have a
larger volume
of it, store it in a separate outbuilding from your system so that if you have a
fire your
stored glycerol will not contribute fuel to the fire.

So what do you do with all that glycerol? I am deliberately a very low volume
producer...every year I set a goal for using less fuel rather than more. This
year I have
finally gotten below 300 gallons per year, which still means I have about 75
gallons of
glycerol to deal with.

There are several pre-disposal options and several disposal options. Let's talk
about pre-
disposal first, which assumes that the glycerol still contains methanol. Here
are the pre-
disposal options I can think of; I hope others will weigh in with other ideas or
correct
these if I got anything wrong:

1. Prior to methanol recovery, separate the glycerol with phosphoric acid.
I have never done this technique, but Dan uses it to separate out the free fatty
acids from
the glycerol. This produces a fertilizer (potassium sulfate,) some FFAs which
can be
incorporated into your next batch, and a higher grade glycerol that can be sold
(you would
have to get an MSDS made for it) to anaerobic digesters as fuel and to car
washes as a
degreaser. The methanol will stay in the glycerol layer because it is
hydrophilic, so you
would still need to recover the methanol from it.

2. Prior to disposal, recover the methanol from the glycerol.
Using distillation techniques, you can recover up to 25% methanol by volume from
your
glycerol. In my experience using a counterflow condenser without a reflux
column, the
grade is about 95% and it's good enough to be used solo in a single stage
process. The
addition of a reflux column would increase the grade so that it would be good
enough for
acid-base. Recovering your methanol reduces the amount of glycerol you dispose,
so for
every 100 gallons of glycerol you start with, by the end of methanol recovery
you should
only have about 75 or 80 gallons of glycerol to dispose of. This glycerol will
still contain
residual methanol so you should be very careful about making it into soap.

3. Prior to disposal, reduce your oil's titration value.
I have only done bench top experiments with this, so I'm no expert. However, you
can mix
the glycerol from your previous batch with the oil from your current batch and
then draw it
off, and you will be left with oil that has a reduced titration value. I believe
that happens is
the methanol and residual lye in the glycerol will help saponify the longer free
fatty acids
which will then be drawn off with the glycerol. I am not certain how much
methanol will be
left in the glycerol you draw off after using this technique.

Here are the disposal options I can think of. Again, please correct and/or add
to what I
have listed here. Also refer to the sideline link associated with this article,
"Glycerol's Role
in 2009," in Biodiesel Magazine:

http://biodieselmagazine.com/article.jsp?article_id=2976

There is work being done to figure out how to convert glycerol into ethanol
which can be
substituted for methanol in the biodiesel process, but as far as I know the
process has not
been scaled for hobbyists.

1. Dispose of glycerol in a properly lined landfill.
Glycerol and methanol will decompose in a properly designed landfill. By
properly
designed, I mean a landfill that is professionally designed and built to include
a clay liner
that will prevent liquids from migrating down to the aquifer. The last thing you
want in the
aquifer is glycerol and methanol! So do *not* dump glycerol, with or without
methanol, in
a dump or, as those idiots in the Missouri Bootheel did, in a waterway. Package
the
glycerol in cubees and dispose of the cubees in a dumpster.

2. Burn de-methanolized glycerol in a wood stove.
This is what happens to the majority of my de-methanolized glycerol. My friend
Karl burns
it in his properly ventilated wood stove. He has tried making vertical "logs"
out of shredded
office paper mixed with glycerol and packed into wax paper milk containers. It's
very labor
intensive. Now he pours some glycerol into a cast iron bread pan, as steel is
too thin and
can't take the heat. Karl's technique would be improved if he had a pump that
would allow
him to add more glycerol to the pan without opening the door. Glycerol burns
very, very
hot, so you have to know what you're doing if you use this technique.

3. Compost de-methanolized glycerol.
You will find all kinds of references to composting glycerol on the Internet,
and many are
of dubious value. If you compost, do *not* just pour glycerol on the ground.
Instead,
incorporate de-methanolized glycerol into a very large compost heap. Glycerol is
"brown"
so you will need a lot of "green" to balance it out. You can't put in too much
glycerol or it
will cause the pile to go anaerobic. Do *not* compost glycerol containing
methanol as the
methanol will evaporate into the atmosphere and, after three chemical steps,
become the
primary greenhouse gas CO2.

I have heard of several people whose local water treatment plant will accept
glycerol with
methanol in it. This is plant-specific, so don't assume that your local plant
wants yours.
You have to contact each plant manager to find out. When I contacted my waste
water
treatment plants in St. Louis, the managers told me they don't want it.

Boutique uses for de-methanolized glycerol include these, which will dispose of
a rather
small amount.

1. Laundry pre-treatment and soap substitute.
Karl washes all his clothes with glycerol instead of laundry soap. He has found
that you
have to air out the clothes after drying to eliminate a glycerol odor, but it
definitely cleans
the clothes. It works great as a pre-treatment for oily spots. If you don't want
to go this
far, you can still use de-methanolized glycerol to clean rags, concrete floors,
cars, etc. I
would not use it on my skin, though, unless you can be sure that you have
removed all
methanol.

2. Bar soap ingredient.
If you make your own soap, you can use de-methanolized glycerol as an
ingredient. Be
very careful to assure that you have gotten all the methanol out of your
glycerol before
making soap out of it. I have written to two of the several little online
glycerol-from-
biodiesel soap people to ask them if they can guarantee that their soap contains
no
methanol, and they didn't even write back. That tells me it's probably risky to
use their
products. FYI I use only the bar soap I make out of virgin oils (palm, coconut,
castor, and
hemp seed) and would not feel comfortable making soap out of glycerol byproduct
unless
I were separating it with phosphoric acid and also recovering nearly 100% of the
methanol
from it with a flash evaporator or falling film evaporator rather than the
counterflow
condenser I currently use.

Well, that's all I can think of for now. Anybody else have any thoughts?

Maud