> His main argument seemed to be against losing the energy in the methanol
>that was washed out
Why "wash" it out? Why not evaporate it and recover it, even as small a
value as it is, rather than flush it with the wash water?
I'll leave the energy and bio-accumlation numbers to the slide rule
folks, but in an efficient setup, the energy used to recover the
methanol from the biodiesel fraction can be used to raise the
temperature of the feedstock for the next batch to the reaction level.
Presume you have a 160* evaporation temperature and the incoming
feedstock is 70*. In a perfect world half of that difference can be
transferred to the incoming oil, raising it to 115*.
Go one step further when drying washed fuel, which may have a pre-dried
temp of 70*F. The diff between 115* and 70* would raise the fuel back up
to approximately 90*.
The wash water is not waste, when all is said and done. It's irrigation.
Recover the soaps by using aluminum or magnesium sulfide (epsom salt),
which converts the water soluble soaps to non-soluble greases. These
have an energy content that can be recovered in a solid fuels boiler.
Or, you can grease the axles of your Sunday-go-to-meetin' buggy.
The water can then be applied as gray water irrigation. The sulfur
content would have to be monitored. But there are crops that tend to
rather like sulfur to a small degree.
At the same time the recovered catalyst (converted to fertilizer) can be
diluted and dispersed with the gray water.
That leaves only the glycerol, either to sell or disperse with the
treated wash water, as the recovered FFAs are returned to the acid cycle
or used as boiler fuel.
Todd Swearingen
skapegoat wrote:
I did notice that a lot of the chemistry in the book was wrong.
His main argument seemed to be against losing the energy in the
methanol that was washed out. He does recommend not using BD with
certain types of tubes, as the methanol will destroy it.
I am certainly planning on washing my BD, I just wonder if he's had
any problems in the ten or more years he's been making his without
washing it.
I know about the chemical equilibrium, and not to try to remove
methanol until the layers are seperated. I'm just wondering if
Tickell is so worried about wasting the methanol by washing it out if
there is a better way of retrieving it without worrying about leaving
all that other garbage in your BD.
*/Keith Addison <[EMAIL PROTECTED]>/* wrote:
Greetings the skapegoat
>The JTF website strongly recommends washing and the Josh Tickell
>book seems to suggest it isn't necessary and possibly even
>detrimental.
Bad book! See:
http://infoarchive.net/sgroup/BIOFUEL/31729/
You might also note that the JtF website says why it strongly
recommends washing, with a couple of references provided (there could
have been plenty more):
http://journeytoforever.org/biodiesel_bubblewash.html#why
Washing: Why bother?
IIRC Joshua Tickell provides one obscure and outdated reference. Rudi
Weidegger of FuelMeister fame (or infamy), who Joshua's since teamed
up with, also recommends no washing and says it's bad for your motor,
with no references, but then he doesn't provide a washtank in his
exorbitant set-up.
Ho-hum.
Anyway, to believe that you'd have to believe that all the national
standards are based on nothing. Some people do seem to believe that.
That's their business, as long as they keep their crappy fuel to
themselves.
>I'm interested in some insight on this difference of opinion. I'm
>sure most experienced biodieselers here wash their biodiesel.
>
>Would it be worthwhile to distill the methanol from the biodiesel
>instead of just washing it away?
The most convenient stage to reclaim the excess methanol would be
immediately after the processing, when the mix is still hot.
Unfortunately that means you reverse the very reaction you've just
completed (hopefully completed). You have to settle and separate the
glycerine by-product first. Most of the excess methanol is in the
by-product; the small proportion in the biodiesel can be recovered,
if you can find an economical way of doing it.
>I know this still leaves excess hydroxides
And soaps.
>that still need to be washed out, but it might reduce the number of
>washes necessary
Doubtful.
>and you might be able to save some of your methanol.
Indeed.
Best wishes
Keith
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