BioDiesel Class 101
Class # 7
- Drying BioDiesel
Drying BioDiesel can be
done in various ways. A lot depends on your local humidity & temperature.
Drying BioDiesel can be as simple as placing a cheese cloth over the top of an
open drum & letting it sit around for a month or two & if you live in a
very hot dry climate a few weeks
may dry it. Most methods of drying will only remove dissolved water &
will not dry up pooled, or high amounts of suspended water which will
eventually drop to the
bottom where it will pool over time.
If your like most
people, you don't have the room or inclination to wait weeks or months for your
BioDiesel to dry so we have a couple of other ways to dry
If you have nice hot dry weather with low humidity (below 50%) you can get away
with simply pumping your BioDiesel through a shower head exposing a large
surface area to the air & allow natural evaporation to take place. If on the other
hand your weather is cool or you have elevated humidity or you expect the
temperature to plummet soon, you will need to heat the BioDiesel and pump it through a shower head to expose a large surface area
to the air allowing evaporation to take place. Both methods work rather
quickly in an hour or two your BioDiesel should be bone dry.
The Drying Method
First, let the BioDiesel sit a few
hours or overnight after doing your last Bubble Wash so any relatively large
droplets can fall out of suspension. Drying works wonders but it can't work
miracles, nothing will remove pooled water except for pumping or siphoning
Using the measurement (BioDiesel to
tank lip) that you took at the beginning of washing, use that measurement as a guide to insure the
wash water level is at least 1"
below the fuel stand pipe drain before starting to drain out your BioDiesel.
Using the Stand Pipe Washers (stand pipe) Fuel
drain fitting, Pump the washed BioDiesel into your Drying tank. For further information on Stand Pipe tanks buy
our PGB book.
You can use our "All in One" low fume
Processor for Drying or a stand alone Drying tank both of these design plans
are in our PGB book which we highly recommend you
get. Either of these Drying tanks work well for drying your BioDiesel
although a stand alone dedicated Drying tank will speed up production
because you can be processing a batch of BioDiesel while your drying another
Using a Pump you will pull washed BioDiesel
from the stand pipe fuel drain fitting in the washer & pump it into your Dryer until you have
emptied out the clean BioDiesel in the wash tank. Some BioDiesel
should remain below the
stand pipe in the washer. Follow up by draining out the wash
water & then catch the last inch or two of wash Water & BioDiesel in a
clean container. Oil cubes from a restaurant work well for this. Let the
cube sit around until the wash water & BioDiesel separate then siphon out
the wash water & any emulsion into another oil cube. Next take your salvaged
BioDiesel & put it into your Drying tank as well. Save the emulsion &
wait for it to break apart in a few days, you can add this BioDiesel to your
Depending on the local temperature &
humidity levels you can choose one of two ways to rapidly dry your
BioDiesel. Air Dry it with heat or just Air Dry it. Both methods circulate
the BioDiesel up through a shower head (as detailed in
our PGB book) to expose broken up
droplets of BioDiesel to the air. Normally drying with heat takes about an hour in 70% or less
humidity, drying without heat in less than 50% humidity can take a similar
amount of time. However drying without heat does have it's risks, see our
book for details.
You will notice the BioDiesel change
it's appearance from a tad cloudy to a bit more transparent. This usually
indicates it is dry. We suggest testing the moisture content before placing
it into your vehicle! Testing is simple & takes only a half an hour or so.
Failure to get dry BioDiesel can damage your fuel injection system & as they say an ounce of prevention is worth a pound of cure.
Besides if BioDiesel contains enough moisture from insufficient drying it can cause water to precipitate
or rain inside your fuel tank if the fuel temperature drops
sufficiently. Water will damage your injection pump & injectors in short
Always test for moisture content 2
ways! Refrigerate a sample at the coldest temperature you
expect for the duration of time that you will be burning that batch of BioDiesel &
look for condensation. Weigh, Heat & dry a sample to verify
And you thought we forgot.....
How long does it take to dry BioDiesel
that is left in a drum & covered with cheese cloth?
Can you dry the water left pooled in
the bottom of the BioDiesel drum?
What is the quickest way to dry your
BioDiesel if the temperature was 45F & the humidity was 80% ?
What will happen to the moisture
content of your BioDiesel if you simply circulate it through a shower head
without heating it & the relative humidity is 95% ? Hint: Get our book
to find out.
How can you tell at what temperature
the moisture (if any) in your BioDiesel will condense out at?
At what temperature do we heat
BioDiesel for drying when using a shower head?
What can occur inside your vehicles
fuel tank if not quite dry BioDiesel is pumped in during the day & the
temperature plummets that night?
What happens if moist BioDiesel in
your vehicle fuel tank condenses out into precipitation and water & is
burned along with the BioDiesel in your vehicle?
Back to BioDiesel 101 class