Page 111 - Air Pollution Control Engineering

02_chap_wang.qxd 05/05/2004 12:40 pm Page 90
90 Lawrence K. Wang et al.

Example 9

Assume that the waste generation ratio is 3.2 gr/ft of HAP emission stream processed, the
3
3
HAP emission stream flow is 110,000 ft /min, and the waste disposal cost is $200/ton-yr,
determine the total annual waste disposal cost for a fabric filtration system.
Solution
1.
gr 11 b 110 000 ft 3 60 min 6000 h
,
.
Waste quantity generated = 32 × × × ×
ft 3 7000 gr min h yr
×
= 1.81 10 × lb
7
yr
2.
×
Annual waste disposal cost =1.81 10 7 lb × ton × 200
yr 2000 lb ton yr
= $1,810,000

Example 10

The HAP emission stream shown in Example 7 and Table 11 is to be treated by a reverse-
air baghouse. Assume the following are the given data:
1. Emission stream flow, Q = 110,000 acfm
acfm
2. System pressure drop = 10 in. H O
2
3. Annual operating hours, HRS = 6000 h/yr (assuming 8 h/shift)
4. Electricity cost = $0.059/kWh
5. Initial bag cost, C = $49,000 from Example 8
B
2
6. Net cloth area, A = 44,000 ft from Example 8
nc
7. Operating labor and labor cost of baghouse at 3 h/shift and $12.96/h, respectively
8. Supervisory cost = 15% of total operating labor costs
9. Maintenance labor and cost of baghouse at 1 h/shift and $14.26/h, respectively
10. Maintenance cost = 100% maintenance labor cost
3
11.Waste generation rate = 3.2 gr/ft of HAP emission stream processed. Waste genera-
tion cost = $1,810,600/yr from Example 9
12. Indirect annual cost = Table 10
Determine the following:
1. Total direct cost
2. Total indirect cost
3. Total annual cost
Solution
1. Total direct annual costs: Electricity usage is estimated using Eq. (10). Assume that
the system pressure drop equals 10 in. H O.
2
−4
F = 1.81 × 10 (110,000)(10)(6,000)
p
= 1.19 × 10 6