Biodiesel Test-Batch Mini-Processor For One or Two Liters

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BiodieselTest-Batch Mini-ProcessorFor One or
Two Liters
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Introduction
This mini-processor is easy to make from not very
much, mostly kitchen stuff and a couple of tools.
It's effective and safe, closed and virtually
air-tight, with no splashing or leaking of hot
fumes. It will make one- or two-liter batches for
test-batch or demonstration purposes, suitable
for single-stage or two-stage processes, with
full agitation and temperature control. And you
can take it anywhere. There's no need to follow
this prescription exactly -- use what's to hand,
improvise. For instance, if you don't have a
plastic drill-grip that will fit a plug spanner
to use for the drill-stand as described below, we
made a second stand using a piece of angle iron
and a strip of 3/32" steel half an inch wide bent
to fit round the drill and clamped in place with
bolts.
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Materials
Three-liter HDPE container with two lids
Spaghetti-cooker -- the bottom and sides of the
inner pot are full of holes like a colander
Electric drill Plastic grip for drill Stand
for the drill Sparkplug spanner Stirrer
Portable gas cooker (canned gas) or electric
hot-plate Two half-liter PET bottles. Cost --
in our case, zero this was all discarded junk,
including the drill, and all in perfect working
order.
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Materials
The drill stand is rigged from scrap angle iron
and welded together, but it could just as easily
be bolted. The bit that holds the drill consists
of the tough plastic grip that came with the
drill, a plug spanner, which conveniently fits
inside the grip, held in place by two bolts
(extra holes mean you can move the drill in and
out from the stand), and the plug spanner is
welded to an extra bit of angle iron bolted
inside the vertical section, again with extra
holes above and below for adjustment. The
stirrer is a length of 6mm steel rod with a slot
cut in the end and a piece of flat steel brazed
into the slot, cut to size so it fits through the
larger of the two HDPE container lids.
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Materials
The lid is fitted with a wooden bush cut from
hardwood with a 6mm hole drilled through it to
take the stirrer shaft. Make it a tight-fitting
hole, then heat a piece of the same steel rod as
the stirrer and push it carefully through the
hole -- not too hot, just enough to scorch the
surface of the wood inside the hole, not char it.
Add a few drops of biodiesel for lubrication. of
the two HDPE container lids. Cut a square hole
in the lid the exact size and shape of the bush
cut another hole in the lid insert. Saw two
shallow grooves on all four side of the bush,
immediately above and below where it will fit the
lid. Push the bush into the hole in the lid push
the insert into the lid around the bush. Secure
with epoxy resin -- push the resin firmly into
the grooves to hold the bush in position. Some
silicon round the seams helps.
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Processes
Heat up the oil in a saucepan on the gas cooker
and pour it into the mini-processor.Slide the
business end of the stirrer inside the processor
and slide the bush in the lid over the other end
screw the lid on firmly. Fill the two half-liter
PET bottles with water at or above the processing
temperature. Put the processor into the spaghetti
cooker wedge in position with a PET bottle on
either side. Add hot water to the cooker to just
below the height of the oil -- as much water as
it will take before the processor begins to
float. Use the gas flame to adjust the water
temperature to the processing temperature, then
turn off the gas.Attach the drill to the stand,
tighten the stirrer in the chuck, switch on and
start stirring.
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Processes
We mix methoxide for test batches in HDPE
chemical bottles, which have a strong lid and a
bung. Drill two holes in a lid and fit two short
sections of plastic or 1/8" (4mm) copper piping,
fix on both sides with strong epoxy resin. To
one, on the inside, fix a length of rigid 1/4
(6mm) plastic tubing that will reach almost to
the bottom of the bottle. To the other, on the
outside, fit a length of flexible 1/4 plastic
tubing. Fit a third section of copper piping to
the small lid of the processor.To add the
methoxide, remove the lid and bung from the
bottle of pre-mixed (cool) methoxide and screw on
the transfer lid tightly.
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Processes
Fit the other end of the length of flexible 1/4
plastic tubing to the inlet pipe in the small lid
of the processor. Now, carefully, lift the
methoxide bottle above the processor and turn it
upside down. Air goes into the open pipe to the
bottom (now the top) of the bottle, methoxide
drains out of the second pipe through the
processor lid into the oil to be mixed. When
all the methoxide has drained, turn the bottle
right way up and put it down on the table beside
the processor. Any stray methanol fumes that
don't condense inside the processor will vent
into the methoxide bottle and condense there.
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Processes
Monitor the temperature with a thermometer,
turning on the heat when necessary -- this is
quite safe, even with gas, as is running the
drill motor, as no methanol fumes escape during
processing. The temperature only needs adjustment
twice in an hour at normal room temperature.
The HDPE container is translucent rather than
fully transparent but it's clear enough to see
the reaction going on inside, and the changing
color and viscosity of the oil.
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Processes
When the process is finished, disconnect the
drill, remove the container and stand it on its
side to settle, small lid down later, to drain
off the by-product, simply tip it up, hold it
over a container and loosen the small lid,
tightening again when you hit the yellow
biodiesel.