the coking properties of coal at elevated pressures. - Argonne ...

all the initial values of x for which xt > 0. Suppose an initial diameter y is
defined so that all particles with an initial diameter x < yo would have buzed
away completely after a time t, then the mass fraction of carbon in the bed at
this time t is
m
m. - =
x=x,
x= z
' $ $(x)dx
where z = x1 if yO&xl
and z = y if yo>xl
X
By substituting y in equation 6) we have
t
f 2
F(C)dt = eyo + - y
i 2 0
0
Combining equations 6), 8) and 10) gives
x= z
Burnout time
To derive an expression for the burn-out time we need to investigate
dm/dt or d(m/mi)/dt. From an oxygen balance on the bed (7) we have
3
where C is the inlet oxygen concentration (mole/m ).
dm/dt
Therefore C = Co + -
P F(Uo)
.J
X
where F(Uo) = 12A[Uo -(Uo-Umf) (exp(-B)) 3
It can therefore be shown that
Also, from equation 13)
r 1
dm/dyo can be found using the mathematical identity,
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