Steve Hanlin said:
> We are trying to determine how to construct an outside tank for storage of
> high fructose corn syrup.
> I am writing to find out if anyone presently uses or knows of anyone who uses
> a tank which is kept outside of a building and if so what kind of precautionary
> measures they use...
I must admit that it sounds cheaper to stick with 55-gallon drums, since
they can be stored anywhere, moved around and heated with a simple
band heater to restore them to liquid form.
> Presently we store approximately 40 fifty gallon barrels in a shop, however
> they do take up a large amount of space and we have a somewhat sticky
> mess year round between the barrels.
Is this really cost-effective? Why not buy on an "as-needed" basis and reduce
or eliminate the "inventory"? There are several sources of wholesale HFCS near
you, and two in Minnesota that specialize in supplying beekeepers. Yes, you
may pay a little more for smaller shipments, but the storage costs and hassles
become zero, so the payback on a "tank" just to keep your bulk price on
HFCS would look very poor.
If you must have a tank, Iowa State has a perfectly good engineering program,
so wander over and ask them to design you an underground tank installation.
If you explain the characteristics of HFCS, they will be able to work it out.
I keep 2000 gallons of #2 fuel oil in an underground tank, and I know first-hand
of several very similar installations near you (Muscatine IA, Omaha, NB, and
Cedar Rapids IA). These are fuel tanks for heating plants and emergency
generators that kick in when power is lost. You don't want the fuel oil to "gel",
and it can sit for months or years before it is needed. When it is needed, it needs
to be pumped within seconds, so the design challenges are very similar to yours.
I can offer a few educated guesses (but check with your local engineers before you
take any of this as "correct" for your application):
If you bury the tank, you get cheap physical support for the tank.
If you bury it well below the frost line, you have a fairly constant temperature.
Putting the highest point about 8 feet deep and filling the 8-foot hole with
a better insulator than earth would be a good idea. Dirt is heavy, which
increases structural load and costs, and it is not a great insulator. (But your
water table depth or bedrock depth may be shallow, consult a soils engineer
or geologist.)
> Another question we have is would it be beneficial to build a protective
> building or walls around the tank to help prevent freezing during the winter
> months.
Expensive. But insulation around the buried tank, wrapped in a vapor barrier
with a surrounding French drain to draw water away from the buried tank
would be a good idea.
> ...have been informed that we would probably have to have a double walled
> metal tank and circulate either hot water or steam to prevent the product
> from freezing.
Wow. Talk about overkill.
Live steam? They must be joking. Imagine the pressure rating of the
"heat exchanger" that would be required. But an internal heat exchanger
of the "warm water" variety might be a nice last-ditch option to liquefy the
tank contents in the event of a "solid lump scenario".
Better to install the vent inside the building, to keep the vent air warm,
and install two pipes to your pump, also inside. Then you can run the
pump to pull syrup out the bottom, perhaps heat it in an off-the-shelf,
propane-powered "instantaneous tankless water-heater" of the sort used
in energy-conserving homes (turned down real low), and pump it back into
the top of the tank via the second pipe. Periodic "stirring" alone might be
enough to keep crystallization down. But, in the event of a worse case
scenario of goo, if you don't have an internal heat exchanger, you open up
the fill tube (assumed to be both outside, and at the top of the tank, and
lower a heater coil down into the tank to heat up the tank contents to the
point where the stuff can be pumped.
But I'd simply buy less at one time, and keep the "inventory" to a minimum.
jim
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