G'day;
Well, I have come across another part of the learning curve.
I was looking at some of your earlier posts, very interesting to
chart your progress in the last six months or so. The learning curve
is a bit like completion in the process, it never quite gets there,
and the curve never flattens either, but you're not rock-climbing
anymore or scaling overhangs, just a gentle incline now.
Someone said learning how to make biodiesel is about as difficult as
learning gardening or how to brew your own beer, which is probably
about right. It's easy, but you don't ever stop learning either. Like
life, eh?
My processor/wash tank combo resides in a non-winterized pump house
and the last two times I have processed a batch of BD (80liters
each) I had a problem with saponification/emulsion and I believe I
have it figured out. As a side note, this probably would not have
happend with KOH, but I am using NaOH at the moment.
The temps here have gone down at night quite a bit of late and this
is the time that the settling is being done. The last two times I
had to heat the plumbing at the exit point of the reator in order to
get the glycerine to flow, at the same time turning on the reactor's
heat for about 30-45 minutes, as the glycerine had hardened in the
plumbing as well as inside the reactor.
Once the glycerine begins flowing it does so very well, HOWEVER it
does not all come out as there is still some that gets "melted"
while the hot BD is being transfered to the wash tank as witnessed
by a sharp darkening of the colour in the sight tube as it comes
out. I immediately stop the pump and drain the remainder out the
glycerine drain at the bottom, but not before some of it has blended
with the BD being transfered and this results in a layer of creamed
chicken soup that won't break. The fuel is good, as the shake test
proves, athough there is glycerine being mixed with the BD, not good.
Solution? Re-heat the lot and pump mix again when hot and let setlle
a few hours and drain, let settle some more and drain again until
the volume approaches what would normally come out the glycerine
drain when the weather is warm.
:-(
Alternative solution? Send the lot, immediately after initial
processing, into a seperate settling tank that has been set up using
the standpipe design (metal tank with bungs downward), let settle
and then drain out the BD FIRST via the standpipe and pumped to the
wash tank, and then flip on the welded immersion heater that has
been inserted near the "floor" of the secondary settling tank
thereby heating the glycerine layer and making it flow easier. A
visual over the edge will tell if the whole glycerine layer got
drained or not and this way NO glycerine is getting in the BD.
That's how we do it with the 90-litre processor.
The processor and holding tank both have a T-section and two valves
fitted to the bottom drain, one valve for draining off the glycerine
by-product, the other for transferring the biodiesel to the washing
tanks via the pump.
We use a couple of short lengths of PVC waterpipe narrowed at one
end to fit inside the outlet drains. The length (height) of the
pipes is calculated to be higher than the depth of by-product in the
bottom of the tank after settling. This "stand-pipe" means the
biodiesel can be pumped out to the washing tanks without getting any
by-product in it. Later we remove the stand-pipe and drain off the
by-product.
The drained glyc comes with a bit of biodiesel left on top, after
it's settled again the biodiesel is easily poured off into whichever
wash tank isn't being used, ready for the next wash.
A couple of times, before I started using the standpipes, I did
manage to get some glyc by-product mixed in with the biodiesel, but
it wasn't a problem. As soon as it was all transferred to the wash
tank I chucked a bucketful of water on top of it, quite roughly, and
left it to settle for an hour, which seemed to remove the glyc, or
anyway there weren't any washing problems after that. It was quite a
lot of glyc, not just a few cc.
Sorry Luc, I've lost track - do you have your secondary settling tank
set up already or is it the intention?
Better system yet? Use potassium hydroxide and don't worry about
theabove time-consuming PITA (Pain In The Anatomy).
Yes. Your winter temps are lower than ours are, but it does hit -15
deg C here (5 deg F) here, and using KOH the glyc has never
solidified.
Anyway, did this complicate your results with the sprinkler wash system?
As still somewhat of a beginner at this BD making stuff I have a
whack of NaOH that I got from a chem supply house that now has to be
used, although once I have thorougly "pefected" using my system and
understanding it's ups and downs to where I ma comfortable with it's
nuances I will be looking into KOH as a catalyst. That will be for
the next season, as this one winds down due to cold and I don't have
the with all to properly insulate the pump house, although I will be
using the off-season to do that as well as set up the secondary
settling tank in preparation for a full and rewarding production
season next year.
The off-season time will also be used to stock up on things like,
methanol and WVO (it's pretty good stuff I get from the Chinese
Restaurant and I want to get ahead of it for next year), and
insulating the pump house which will allow me to get going earlier
than if I only wait for it to be warm enough in the Spring.
Ordering some WintronXC30 is also on the list for early Spring use
and also for next winters' BD experience.
It is too bad too as the Benz REALLY likes running on B100, and it
iwll do so once weather and the ability to process permits. Who
knows, maybe it will be sooner rather than later, but one thing
certain, I will be working at it.
An Espar or Webasto and some of the other measures detailed on our
Biodiesel in winter page would sort it out, but it'd probably sort
your pocket out too, not very cheap.
http://journeytoforever.org/biodiesel_winter.html
Regards
Keith
Luc
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