pa1778data.pdf

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U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 100)
The rotating nozzles at the top of the scrubber were
replaced by two sets of seven upward pointing nozzles which were
positioned across the diameter of the scrubber and inserted one
above the other. Incoming water entered the scrubber through a
cut off valve located at each set of nozzles and was forced
upwards through two screens, placed at six foot intervals, before
falling back through them in the form of droplets. The 5 hp
motor driven cut off valves were composed of a series of openings
or ports, one for each nozzle, which were successively blocked by
a revolving core located inside of the valve. Consequently, the
valves shut off the water leading to each nozzle in turn, making
an area of low resistance over the temporarily dormant nozzle.
As the gas was naturally directed to the area of low resistance,
the water was turned on again thereby deflecting it to the next
nozzle. In this manner a spiral motion was created which gave a
larger exposure of the gas area to the washing water than would
normally result. As such, the principle of using water to guide
the passage of the gas in the scrubbers, in what became known as
the Diehl spray gas washer, became one of the standard methods
employed in industry-wide wet systems over the next half-century.
After four years of meticulous documentation the results of
the experiment markedly favored the wet gas cleaning system.
While the hot blast stoves using gas from the more traditional
cleaning system continued to be taken off line every two months
for cleaning, the stoves which used gas from the wet system
operated continuously over the course of the experiment. Lower
moisture levels in the gas emanating from the wet system resulted
in higher burning efficiency when compared to the gas flowing
from the more traditional system. Furthermore, when comparing
the cost of constructing and maintaining the equipment used in
the wet system to the cost of maintaining the hot blast stoves
operating under the old system it was found that gas cleaned by
the wet system saved the plant 0.1591 cents per ton of iron. An
additional advantage of the wet system was that the relatively
clean gas it produced allowed furnace men to decrease the
openings in the checkerwork of the hot blast stoves thereby
substantially increasing the total heating surface of each stove,
which resulted in the production of higher hot blast
temperatures. As a result, the experiment not only substantiated
the value of the wet gas cleaning system for the production and
delivery of combustion air at the Duquesne blast furnace plant
but proved its merit for the entire industry as well.
Between 1908 and the early 1940s the physical features of
the combustion air and production system at Duquesne remained
constant. Between 1943 and the early 1980s, however, the system
became the focal point of a number of significant experiments.
Moreover, the period witnessed installation of major pieces of