Appendix C

EQUIPMENT COST MODEL

[Adapted with permission from J.D. McKenna, ETSI Inc, Roanoke, VA, 2008]

A simple method for determining costs associated with air pollution controlequipment is presented below. To simplify the presentation, only costs associatedwith baghouses will be considered. However, the algorithm can easily be extended toinclude all other plant or environmental equipment.

As with most economic/cost models involving (plant) equipment, there are twoclasses of cost that need to be considered.

1. Capital investment

2. Operation and Maintenance (O & M) costs

Specific information follows.Capital investments can be divided into four general categories.

1. Control equipment hardware costs

2. Auxiliary equipment costs

Air Pollution Control Equipment Calculations. By Louis TheodoreCopyright # 2008 John Wiley & Sons, Inc.

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3. Field installation costs

4. Engineering studies, land, preparation, initial inventory, strucure modification(s),and start-up

There are 6 basic factors that must be considered with regard to annual O & M costs.

1. Gas volume

2. Pressure drop

3. On-steam time

4. Electricity

5. Mechanical efficiencies of the fan(s)

6. Filter bag replacement

It is not uncommon to split the O & M costs into two categories: Operation andMaintenance. These two costs may be determined from Equation (C.1).

G ¼ Aþ Bþ Cþ D (C:1)

where G ¼ Annual operating and maintenance cost

A ¼ Electrical cost

B ¼ Liquid consumption cost

C ¼ Fuel cost

D ¼Maintenance cost

For a baghouse, the above equation reduces to

G ¼ Aþ D (C:2)

since B ¼ 0

C ¼ 0

The standard electrical cost component of the above equation is given by

A ¼ 0:74576356E

� �(P)(H)(K)(S) (C:3)

where S ¼ Design capacity of baghouse fabric filter in acfm

P ¼ Pressure drop in H2O

E ¼ Fan efficiency

H ¼ Annual operating time in hr

K ¼ Power cost, $/kW . hr

0.7457 and 6356 are conversion constants

APPENDIX C564

Thus, the annual O & M costs become

G ¼ S(0:7457)(P)(H)(K)

(6356)(E)þM

� �(C:4)

Finally, the total annualized cost is given by

T ¼ Gþ Xþ Y (C:5)

where T ¼ Total annualized cost (as described in text)

G ¼ Annual costs for operation maintenance

X ¼ Annualized capital costs

Y ¼ Depreciated capital investment

ILLUSTRATIVE EXAMPLE

Estimate the total annualized cost for a baghouse given the following data.Capital charges:

Initial capital cost, ICC ¼ $153,700

Annualized capital costs, ACC ¼ 18% of ICC (CRF ¼ 0.18)

Depreciated capital investment ¼ 6.67% of ICC

Operating information:

Gas flowrate ¼ 70,000 acfm

Pressure drop ¼ 6.0 in H2O

Fan efficiency ¼ 60%

Annual on stream time ¼ 6000 hr

Electrical cost ¼ 0.05 $/kW . hr

Maintenance information:

Number of bags ¼ 1080

Bag life ¼ 4 yr (25% replacement per year)

Bag replacement cost ¼ $100/bag

Routine maintenance time ¼ 4 hr/week

Labor cost ¼ $20/hr

Solution: First calculate the annual maintenance cost in $/acfm.

M ¼ M1 þM2

APPENDIX C 565

where M1 ¼ Bag replacement cost

M2 ¼ Bag house routine maintenance cost

Employing the maintenance data provided,

M ¼ [(1080)(0:25)(100)þ (4)(52)(20)]=70,000

¼ [$27,000þ $4160]=70,000 acfm

¼ 0:45 $=acfm

Equation (C.4) is employed to obtain the annual O & M cost.

G ¼ S(0:7456)(P)(H)(K)

(6356)(E)þM

� �

¼ (70,000)(0:7456)(6)(6000)(0:05)

(6356)(0:6)þ 0:45

� �

¼ $56,138

The total annualized cost can now be calculated from Equation (5)

T ¼ Gþ Xþ Y

¼ 56,138þ (0:18)(153,700)þ (0:067)(153,700)

¼ 56,138þ 27,666þ 10,296

¼ $94,000

APPENDIX C566