Tímarit Verkfræðingafélags Íslands - 01.12.1967, Síða 102

100
TÍMARIT VFl 1967
places that heat can be produced that cheap
with conventional fuels.
Freeze-dried products have many advantages,
such as the fact, that the weight of the finished
products — for instance fish — is only about
20% of the raw-product. No refrigeration or
similar costly methods are required for keeping
the product. In this respect freeze-dried pro-
ducts are comparable to the fish-protein con-
centrate which will be discussed later in this
conference. On the other hand, freeze-dried fish
can be reconstituted, as such, at the consumer
end.
In this connection I hope I will be excused
if I quote Dr. Pariser’s paper, which has not
yet been read. Dr. Pariser quotes the processing
cost for fish protein concentrate as about 14
cents per pound of the finished product. This
includes the price of fish at 1 cent per pound,
and that corresponds to about 6,7 cents per
pound in the price of the finished products, if
the yield is 15% as quoted. As a comparison, I
mention from Dr. Petersen’s paper that the
total processing cost in freeze-drying is 7V2-15
cents per kg of water evaporated. This corres-
ponds in the case of fish to approximately
13-26 cents per pound of freeze-dried product.
If we add to this 5 cents per pound for the
raw-fish at the same priee, one cent per hour,
we get about 18-31 cent per pound as a compar-
able figure to the 14 cents per pound for the
FPC, quoted by Dr. Pariser. In other words,
according to those figures, the price difference
is only of the order of 30-80%. This is not
much of a difference when you keep in mind
that in the case of the freeze-drying you can
offer the consumer practically the natural
product, whereas in the case of the FPC, you
have a product that is vastly different from
the original one, even if it is in all other respects
a first class product.
I am aware of the danger of making this
comparasion, and it applies only to the orders
of magnitude, the figures may not be found
entirely on the same basis. But I would like to
point out that due to the special circumstances
here in Iceland, the low energy cost, and the
fact that we have enormous potential of low-
priced fish, the herring, which is not used per-
haps in the best way as yet, I do suggest that
it would be worth studying, whether those two
resources could be connected together in a
profitable way.
Pétur Sigurjónsson:
I would like to thank Mr. Begtrup-Hansen for
this article. What we have seen here is the be-
ginning of a new industry and we have had
it pointed out that the development of the
machinery is still going on very fast, and in
two respects.
Firstly to cope with the high costs of the
final product as it is now, and also to find
out new types of products.
As we have heard here the main costs are
the capital cost and the costs of energy.
But I know there is an enormous lot of
research done in this field, and the machinery
we have seen here is — as we could say — a
more universal apparatus where you could
freeze-dry anything you want.
But in the latest developments, you go on
to more specialized machinery where you take
account of the product you are going to use
and then construct the machinery with that
in view. It is about these latest developments in
this field that I would like Mr. Begtrup-Hansen,
to teil us.
There is the new cylinder freeze-drying
machinery, where you, for instance in the
“Dutch Sheffingsystem”, fill in the cylinder and
freeze a layer of the product on the inside of
it through the evaporation of ammonia.
When the layer of products is frozen you
put on vacuum, and by reversing the process
you heat up the cylinder by compressing the
ammonia again — so you have a sort of a
heat-pump.
This process is claimed to be only half as
expensive as the conventional freeze-drying as
we have seen it here to-day.
The United States Department of Agriculture
is also developing a cylinder freeze-drying
process where you transfer the heat to the
goods — granulated goods — with rotating fins.
You get a very intensive heat-transfer and very
short drying time, even down to 3 hours, so the
processing cycles are very short and the capital-
costs are lower.
Then there is also new Spray freeze-drying.
As you have seen here to-day they are going
away from contact-heating over to radiant-
heating, and there are developments in short-
wave-heating also to make the process still
more economical and intensive.
These are the questions I would like to have
cleared.