That fat acid at the high temperature
soon attacks your boilers and pipes, and eats away the iron. That is one
of the curious results that may follow at such high temperatures.
Mineral or hydrocarbon oils do not contain these fat acids, and so
cannot possibly, even with high-pressure steam, corrode the boiler
metal.
_Effect of Dissolved Salts on the Boiling of Water._--Let us inquire
what this effect is? Suppose we dissolve a quantity of a salt in water,
and then blow steam at 100 deg. C. (212 deg. F.) into that water, the latter
will boil not at 212 deg. F., but at a higher temperature. There is a
certain industrial process I know of, in course of which it is necessary
first to maintain a vessel containing water, by means of a heated closed
steam coil, at 212 deg. F. (100 deg. C.), and at a certain stage to raise the
temperature to about 327 deg. F. (164 deg. C.). The pressure on the boiler
connected with the steam coil is raised to nearly seven atmospheres, and
thus the heat of the high-pressure steam rises to 327 deg.
Pages:
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67