pa1778data.pdf

U.S. STEEL DUQUESNE WORKS
HAER No. PA-115
(Page 105)
took the ostensibly clarified water back to the river while the
sludge was pumped to the settling basins where it was removed by
grab bucket after drying. 6
Major construction projects involving blast furnaces number
four and six between 1959 and 1962 significantly altered the
make-up of the combustion air production and delivery system. As
part of a major rebuild of blast furnace number four in 1959, new
21'-0" diameter x 121'-0" high hot blast stoves were installed by
the William M. Bailey Company. The 150,428 square feet of
heating capacity in each stove was by far the largest heating
area among existing hot blast stoves in the blast furnace plant.
This record, however, was quickly surpassed by the construction
of the hot blast stoves associated with the Dorothy six complex
in 1962. Designed and installed by John Mohr and Sons Inc., each
of the three 32'-0" diameter x 130'-0" high stoves contained a
total heating surface of 450,781 square feet. Other important
equipment relating to the combustion air production and delivery
system which were part of the construction of Dorothy Six
included the installation of an axial turbo-blower, a new gas
cleaning apparatus, and a continuous process for dewatering blast
furnace sludge.
The axial turbo-blower, designed and built by the Elliott
Company of Jeannette, Pennsylvania, had the capability of
delivering 155,000 cfm of air at 55 psi to Dorothy Six. The
first axial machine in the United States to go into service in
the active production of iron, the adjustable blades at the
compressor end of the turbo-blower allowed for the delivery of
different volumes of air to the furnace. This made it possible
to produce, in a controlled manner, different types of pig iron.
The gas cleaning equipment at Dorothy Six, consisting of a
dust catcher, a 190,000 scfm venturi type primary gas washer and
a 190,000 scfm gas cooling tower linked together in series. It
represented a first step away from the plant's traditionally
centralized gas cleaning operation. Gas flowing from the top of
the furnace was first passed through the dust catcher where the
large entrained particulate were removed from it in the usual
manner before it was taken to the top of the venturi type
primary gas washer. The gas washer consisted of a venturi shaped
unit connected to a 21'-0" diameter x 49*-6" high tile lined
hollow cylinder. Gas entering the top of the venturi unit was
forced through its narrow throat where it was sprayed at a rate
of 2400 gpm with water by low and high pressure nozzles set at
different angles. Upon spraying, the gas, containing .01 grains
of flue dust per cubic foot, was led out of the washer through a
84" i.d. connection located near the top of the cylindrical
structure set below the venturi unit to the gas cooling tower.