"Tim Wescott" wrote in message
...
On Thu, 23 Aug 2012 21:04:08 -0500, RogerN wrote:

Been looking a little at ethanol production, I hear it's cheaper to make
from sugar than it is from corn or grain mash. If it took a lot of
continuous work I wouldn't mess with it because I have more important
things to do with my time, I get paid more for overtime at work than I
could save on fuel.

So anyway in my hobbies I mess with automation and controls, I have a
dozen or so PLC's around here to play with or make things with. I have
thermocouple, RTD, and other assorted I/O modules for the PLC's.

If I could weigh up sugar, mix with water, and add yeast automatically,
transport to a fermentation tank, wait a few days, maybe having a few
small fermentation tanks, I could get a somewhat steady supply of
alcohol/water. Then for the distiller, use a continuous mode where mix
is added in, alcohol is evaporated out the top and water goes out the
bottom. It would seem that with a properly sized heating element, it
could be left on high and the temperature controlled by the flow of
alcohol/water going into the boiler. If the top of the fracturing column
is at alcohol temperature, slow or stop the inflow, as alcohol is
evaporated the temperature should rise the flow coming in could be
increased. Should all be pretty much automatic, shouldn't need a larger
boiler or still since there would be a constant supply of alcohol /
water until the fermentation tank was empty.

It seems like with a few valves, tanks, and a pump, plus the boiler and
a chilled receiver, alcohol production may be do-able without too much
daily time and effort. Not sure it would save enough money to pay for
itself but a small continuous type setup seems like it could cut a lot
of the labor out.

RogerN

I'm not sure that a continuous system is even going to work -- alcohol
and water are quite happy together, and you're bound to have convection.
I think the only alcohol on the "top" is going to be the stuff that's
boiled off.

So I think you're doomed to have some sort of a batch process. Putting
in the next batch of fermented stuff as you draw out the spent batch
would help with the energy efficiency, particularly if you make up some
sort of a heat transfer gizmo.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

The amount of heat that ends up in the alcohol itself isn't a whole lot,
with most of the heat used in distilling simply being spent in raising the
entire wash temperature to the point at which the alcohol(s) boil off...

--if you want to drink it, first you raise (and hold) the temp till all of
the methanol boils off, discarding that because it's poison...after this,
you again raise the temperature till the ethanol boils off, holding it there
and collecting....now what you finally will have left is mostly hot water
and dead yeast, easy enough to recover the heat from that concoction by
using a counterflow chiller but unless you have another batch that's all
ready to go or you have some other use for hot water then there's really not
much sense..