capital and manufacturing cost estimation.ppt

8/10/2019 Capital and Manufacturing Cost Estimation.ppt

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Capital and ManufacturingCost Estimation

Jim Frederick

CHBE4505A

Summer, 2005


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Capital Cost Estimation

Purchased vs. installed cost, etc.

Use simple estimation methods Cost vs. capacity power law scale-up

Cost factors or equations from equipmentvendors

Cost charts from plant design textbooks, etc.

Cost estimates from web sites

Inflation factors


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Cost Estimation Terminology

Cp= Purchased cost This is what you pay the vendor for the equipment

CBM= Bare module cost Cost of the equipment plus installation

CTM= Total module cost Cost of addition of equipment or minor expansion

Includes contingency and costs and other fees

CGR= total grass-roots cost Cost of a new mill or major mill expansion

Includes a site development, auxiliary buildings, etc.


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Cost vs. Capacity Power LawScale-up

Power law equation:

Cp,2/Cp,1= (Capacity2/Capacity1)n

For process equipment, nis equipmentspecific, range from 0.41 (heat exchangers) to 1.15

(jaw crushers) For an entire plant, use n= 0.6

CGR,2/CGR,1= (Capacity2/Capacity1)0.6


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MaterialsSelection

Factors:

Temperature

ChemicalEnvironment

Pressure

Stress-temperature relationships for important metals and alloys. (Source:Ulrich, 1984)

Temperature, oC

Allowablete

nsilestress,

bar


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Cost Factors or Equations FromEquipment Vendors

Cost factors (apply for a narrow size range)

Installed cost for black liquor evaporators:

$60/ft2heat transfer area Installed cost for kraft recovery boilers: $11 to

$13 per lb BL solids/day

Cost equations (apply over a wider size range)


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Example of a Cost Equation (1/2)

A. Cost equations:

For effects in a multiple-effect evaporator operating with black

liquor above 30% solids content and/or at pressures above 1atm,

CBM= $1,770 A0.55

For evaporator effects operating with black liquor at or below

30% solids content and/or at pressures at or below 1 atm,

CBM= $830 A0.55

Note: in both correlations, where A = heat transfer area, ft2


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Example of a Cost Equation (2/2)

B. Size limitations:

The largest dimple plate, falling film evaporator unit in the

world: evaporates 2.2x106pounds of water per hour,

contains 628,000 ft2of heat transfer area (~147,000 ft2

per effect for the 6-effect train)

The 6theffect is 34 ft in diameter

Be aware of min and max equipment sizes in normaldesign practice


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Cost Estimation Charts

Based on data from many plants

Procedure

estimate Cp,csfor equipment constructed fromcarbon steel, and to operate at or only slightlyabove one bar

Determine the factors for materials other than

carbon steel, pressure, etc.

Calculate CBM from Cp,csand these factors

Each chart has a specific equation for CBM= f(Cp,cs)


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Max

size

Min

size


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From Cpto CTM

1. Account for inflation

Use the ratio of the Chemical Engineering Plan CostIndex (CE Index) for the year of purchase and the yearon which the purchased cost estimation is based, i.e.

CBM,2006= CBM,1978(CE Index2006/CE Index1978)

Account for cost of installation, etc.

Add contingency + fee = 0.18 FBM

Simplest: use Lang factor: fLang= CTM/Cp

fLang= 4.5 for chemical plants, 3.2 for solids processing

plants, and 2.5 for P&P mills

capital and manufacturing cost estimation.ppt

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