TM 5-815-1/AFR 19-6
6-9.
Advantages and disadvantages
struction. Erosion life of a cyclone may be extended by
using harder and thicker grades of steel. A stainless
a. Advantages. The advantages of selecting cyclones
steel of 400 Brinell rating or better is normally chosen
over other particulate collection devices are:
for cyclones subject to erosive conditions. When ero-
-- No moving parts,
sion is extreme, it is necessary to provide for replacea-
-- Easy to install and replace defective parts,
ble liners in cyclone construction. Liners are made of
-- Constructed of a wide variety of materials,
hard stainless steels or erosion resistant refractory. In
-- Minimum space requirements,
low temperature fly ash applications, cyclones of mild
-- Designed to handle severe service conditions
steel or iron can be used because dust loadings are
of temperature, pressure, dust loading,
generally too small to cause appreciable erosion. Cast
erosion, corrosion, and plugging,
iron is most often used in multicyclones in boiler ser-
-- Can be designed to remove liquids from gas,
vice.
-- Low capital costs,
c. Temperature. Cyclones operated above 800
-- Low maintenance costs.
degrees Fahrenheit cannot be constructed of mild
steels because the metal will creep and form ridges or
b. Disadvantages. The disadvantages of selecting
buckled sections. Above 800 degrees Fahrenheit,
cyclones over other particulate collection devices are:
nickel-copper bearing steel such as Monel is used to
-- Lower collection efficiency,
provide added strength. when temperatures are in
-- Higher collection efficiencies (90-95 percent)
excess of 1000 degrees Fahrenheit, nickel-chromium
only at high pressure drops (6 inches, water
steel of the 400 series is used in conjunction with
gauge),
refractory linings. Silica carbide refractories provide
-- Collection efficiency sensitive to changes in
excellent protection against erosion and high
gas flow, dust load, and particle size
temperature deformation of the cyclone metal parts.
distribution,
-- Medium to high operating costs.
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