TM 5-815-1/AFR 19-6
degrees Fahrenheit for maximum sulfur
throughout the process because of the
retention. The hot gases are separated from
high turbulence and circulation of solids.
the dust particles in a cyclone collector. The
The low combustion temperature also
materials collected are returned to the
results in minimal NOx formation.
(c)
combustion
chamber
through
a
Sulfur present in the fuel is retained in the
nonmechanical seal, and ashes are removed at
circulating solids in the form of calcium
the bottom. The hot gases from the cyclone
sulphate soit is removed in solid form.
are discharged into the convection section of
The use of limestone or dolomite
a boiler where most of the heat is absorbed to
sorbents allows a higher sulfur retention
generate steam. Typical fluidized bed boilers
rate, and limestone requirements have
of this type are as shown in figure 13-6.
been demonstrated to be substantially less
(3) Major performance features of the circulating
than with bubbling bed combustor.
(d)
bed system are as follows:
The combustion air is supplied at 1.5 to 2
(a) It has a high processing capacity because
psig rather than 3-5 psig as required by
of the high gas velocity through the
bubbling bed combustors.
(e)
system.
It has a high combustion efficiency.
(b) The temperature of about 1600 degrees
(f)
It has a better turndown ratio than bub-
Fahrenheit is reasonably constant
bling bed systems.
13-4
Previous Page
