Page 419 - Air Pollution Control Engineering

09_chap_wang.qxd 05/05/2004 5:01 pm Page 391
Catalytic Oxidation 391

Note that this inlet temperature results in T = 1000ºF
co
2. Determine Q (assume recuperative heat recovery will be employed):
f
Q = 20,000 scfm
e
T = 77ºF
r
T = 560ºF (based on HR of 50 percent)
he
C p = 0.253 Btu/lb-ºF
air
D = 0.0739 lb/scf
e
h = 21,600 Btu/lb
f
0 0739 (20 000 0 253, )[ . (984 − 560 − 7 7 )]
.
.
Q =
f ))]
.
0 0408 [ 21 600, − (1 1. (0 253. )(895 − 77
Q = 179 scfm
f
Example 8
It is assumed that dilute emission streams that require no additional combustion air will be
treated by a catalyst incinerator. Outline a step-by-step procedure for determination of (1)
the flow rate of combined gas stream entering the catalyst bed, (2) the flow rate of flue gas
leaving the catalyst bed, and (3) the catalyst bed volume required for the treatment.
Solution
1. Determination of the flow rate of combined gas stream entering the catalyst bed. For
dilute emission streams that require no additional combustion air, use
Q = Q + Q + Q (6)
com e f d
Q = scfm
com
2. Determination of the flow rate of flue gas leaving the catalyst bed
a. Use the result from the previous calculaton:
Q = Q com
fg
Q = scfm
fg
If Q is less than 2000 scfm, define Q as 2000 scfm.
fg fg
b. Use Eq. (8) to calculate Q .
fg,a
Q = Q [(T + 460)/537] (8)
fg,a fg co
Q = acfm
fg,a
3. Determination of the catalyst bed requirement. Use Eq. (9) to estimate the catalyst bed
volume.

V = 60 Q /SV (9)
bed com
V = ft 3
bed
Example 9

Use the step-by-step procedure outlined in Example 8 to determine the following when a
catalytic incinerator treats the HAP emission stream documented in Table 1:
1. The flow rate of combined gas stream entering the catalyst bed, Q
com