pa1778data.pdf

U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 99)
cfm, it was washed by 815 gpm of water issuing downward from a
rotating nozzle. The water passed through a series of screens so
that it formed rain like droplets for the purpose of creating
direct contact between the water and the incoming gas. Upon
leaving the top of the scrubber, the gas was blown through the
Sturtevant fans into the clean gas main where most of it was
diverted to the boilers and hot blast stoves at blast furnaces
number three, four, five and six. The remainder was taken to the
Theisen washers in preparation for delivery to the gas blowing
engines. Each of these washers consisted of a stationary
horizontal cylinder which enclosed a smaller 150 hp motor powered
revolving cylinder, on the shell of which was mounted twenty-four
steel vanes. Gas was admitted at one end of the cylinders while
low pressure water dashed to a spray by the revolving vanes was
admitted through the outer cylinder by six pipes at the opposite
end. Because the gas and the water were traveling in opposite
directions they were thoroughly mixed, thus wetting the small
particles of dust which therefore separated out with the water.
Upon exiting the Theisens, the gas was cleaned to an average dust
content of less than one-hundredth grain per cu. ft.
^P Slurry from the scrubbers and Theisens was drained to a
settling basin located adjacent to them. The 26'-0" wide x 161'-
0" long x ll'-6" deep basin (settling depth equaled 6'-0") was
divided into ten sections each with equal sub-divisions
representing half of the section. Slurry was deposited
successively into each of the sections* sub-divisions. As the
dirt and water filled up a sub-division, the water was drained
through a sewer into the Monongahela River while the sludge,
which was high in iron content, was loaded by a grab bucket into
a railroad hopper car for delivery to a local sintering plant
where it was agglomerated prior to being recharged into the top
of the blast furnaces.
Early efforts to conduct the experiment were stymied by the
poor performance of the gas scrubbers. This was due to the
inability of the washing water to come into intimate contact with
the gas rising through the scrubber because the high velocity of
the ascending gas deflected the water, thereby creating a channel
through which the gas escaped without being cleaned of its
entrained particulate. A corrective to the problem was found by
making the washing water, as opposed to the gas, the dominant
element in the system by delivering the water in such a manner as
to change the direction of the gas in its upward movement while
at the same time spraying it repeatedly. In order to accomplish
this objective, a new system of delivering the scrubber washing
# water was devised. It consisted of cut off valves, stationary
nozzles, and an altered relationship between the nozzles and the
screens.