The chemical factory, Eisenbuettel, near Braunschweig, distributes the
following circular: "The principal generators of incrustation in boilers
are gypsum and the so-called bicarbonates of calcium and magnesium. If
these can be taken put of the water, before it enters the boiler, the
formation of incrustation is made impossible; all disturbances and
troubles, derived from these incrustations, are done away with, and
besides this, a considerable saving of fuel is possible, as clear iron
will conduct heat quicker than that which is covered with incrustation."
J. Kolb, according to _Dingler's Polyt. Journal_, says: "A boiler with
clear sides yielded with 1 kil. coal 7.5 kil. steam, after two months
only 6.4 kil. steam, or a decrease of 17 per cent. At the same time the
boiler had suffered by continual working."
Suppose a boiler free from inside crust would yield a saving of only
5 per cent. in fuel (and this figure is taken very low compared with
practical experiments) it would be at the same time a saving of 3c. per
cubic meter water. If the cleaning of one cubic meter water therefore
costs less than 3c., this alone would be an advantage.
Already, for a long time, efforts have been made to find some means for
this purpose, and we have reached good results with lime and chloride of
barium, as well as with magnesia preparations. But these preparations
have many disadvantages. Corrosion of the boiler-iron and muriatic acid
gas have been detected. (Accounts of the Magdeburg Association for
boiler management.)
Chloride of calcium, which is formed by using chloride of barium,
increases the boiling point considerably, and diminishes the elasticity
of steam; while the sulphate of soda, resulting from the use of
carbonate of soda, is completely ineffectual against the boiler iron.
It increases the boiling point of water less than all other salts, and
diminishes likewise the elasticity of steam (Wullner).
In using magnesia preparation, the precipitation is only very slowly and
incompletely effected--one part of the magnesia will be covered by the
mire and the formed carbonate of magnesia in such a way, that it can no
more dissolve in water and have any effect (_Dingler's Polyt. Journal_,
1877-78).
The use of carbonate of soda is also cheaper than all other above
mentioned substances.
One milligramme equivalent sulphate of lime, in 1 liter, = 68 grammes
sulphate of lime in 1 cubic meter, requiring for decomposition:
120 gr. (86-88 per cent.) chloride of barium of commerce--at $5.00 =
0.6c.
Or, 50 gr. magnesia preparation--at $10.00 = 0.5c.
Or, 55 gr. (96-98 per cent.) carbonate of soda--at $7.50 = 0.41c.
The proportions of cost by using chloride of barium, magnesia
preparation, carbonate of soda, will be 6 : 5 : 4.