pa1778data.pdf

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U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 98)
on the fine particles of flue dust which remained entrained in
the gas after it left the dust catcher. Much of this dust passed
up through the stoves■ combustion chambers and became lodged in
their checkerwork, thus constricting the openings provided for
the passage of the gas as well as the cold blast air. Over time
the checkerwork openings became completely clogged, rendering the
stoves incapable of absorbing heat or giving it up. As a result,
each stove had to be taken off line for a period of five or six
days every two months for a complete cleaning which meant that
for one-third of its time in operation the blast furnaces were
deprived of one-fourth of their heating surface capacity.
The decision to use four 3600 hp gas fired blowing engines,
manufactured by the Snow Steam Pump Works, for the production of
cold blast air at blast furnaces number five and six increased
the need to provide the appropriate blast furnace plant equipment
with clean gas. Because the engines required fuel gas almost
completely free of entrained particulate, plant officials were
faced with the prospect of furnishing them with very clean gas
from the blast furnaces or buying natural gas from outside
sources.
In view of the difficulties experienced in the original
system of producing and delivering combustion air to the blast
furnaces, plant officials in 1908, led by Ambrose N. Diehl,
superintendent of the blast furnace plant, devised an
experimental gas cleaning plan. An industry wide pioneering
effort, the four year long experiment was set up to compare the
more traditional gas cleaning approach to a newly conceived wet
gas cleaning system in terms of efficiency and cost
effectiveness. In both systems gas flowing from the dustcatcher
at each blast furnace was directed through an additional
dustcatcher per furnace before it was combined into a single 8'-
6" diameter rough gas main. From the rough gas main a portion of
the gas was taken directly to the boilers and hot blast stoves at
blast furnaces numbers one and two while the rest of it was
conducted to the newly constructed wet system.
The wet system, which was laid out linearly, consisted of
nine 12 ! -0" diameter x 76'-0" high scrubbers arranged in
parallel, four electric motor driven Sturtevant fans, each with a
capacity of 84,000 cfm, and four horizontal Theisen gas washers.
The scrubbers were theoretically designed to clean the gas to
within one-fifth grain per cu. ft. while cooling it in order to
remove most of its moisture, thus increasing its B. T. U. value.
Under the experiment's original conception, gas traveling through
the rough gas main leading to the wet washing system was first
introduced into the bottom of one of the scrubbers. As the gas
was rising up through the scrubber at a maximum rate of 30,000