Page 112 - Air Pollution Control Engineering

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Fabric Filtration 91

6
Electricity cost = $0.059(1.19 × 10 ) = $70,200/yr
Because reverse air is used, P = 0.
ms
Bag replacement costs are obtained using Eq. (12):
C = [49,000 + 0.14(44,000)]0.5762
RB
= $31,800/yr
Operating labor costs are estimated as

[(3 h/shift)/(8 h/shift)]6,000 h/yr = 2,250 h/yr
2,250 h/yr ($12.96/h) = $29,200/yr

Supervisory costs are taken as 15% of this total, or $4370.
Maintenance labor costs are estimated as

[(1 h/shift)/(8 h/shift)]6,000 h/yr = 750 h/yr
750 h/yr ($14.26/h) = $10,700/yr

Maintenance materials are taken as 100% of this total, or $10,700.
Waste disposal cost = $1,810,600/yr from Example 9
Total direct annual costs = $70,200 + $31,800 + $29,200 + $4370 + $10,700 + $10,700 +
$1,810,000 = $1,970,000
2. Total indirect annual costs: These costs are obtained from the factors presented in
Table 10 and the example case presented above.
Overhead = 0.60($29,200 + $4370 + $10,700 + $10,700)
= $33,000
Administrative = 0.02($1,920,000)
= $38,400
Insurance = 0.01($1,920,000)
= $19,200
Property taxes = 0.01($1,920,000)
= $19,200
Capital recovery = 0.1175($1,920,000) − 1.08($49,000) − 0.05($0.14)(44,000)
= $219,000
Total indirect costs = $33,000 + $38,400 + $19,200 + $19,200 + $219,000
= $329,000
Total annual costs = $1,970,000 + $329,000
= $2,200,000/yr

Example 11
The bag prices shown in Table 8 are for the third quarter 1986. Discuss how one can update
the third quarter 1986 cost to the March 2002 cost, or any month in the future.

Solution
Using the following equation for equipment cost comparison:

Cost = Cost (Index )/(Index )
b a b a
where Cost is the future cost ($), Cost is the old cost ($), Index is the future CE equip-
b a b
ment cost index, and Index is the old CE equipment cost index. For instance, the CE
a
(Chemical Engineering) equipment cost index for the third quarter 1986 can be obtained