1. Chapter 22 (p558-597) CH EN 4253 Terry A. Ring
Equipment Costing
Chapter 22 (p )
CH EN 4253
Terry A. Ring

2. 6/10th scale up/down Factor
Used for scaling the total capital cost for a chemical plant of a different size
Cost2/Cost1 = (Capacity2/Capacity1)0.6
Accounts for economy-of-scale

3. Accounting for Inflation
Cost to purchase = Base Cost*(I/Ibase)
Base Cost, CB, = Historical price at Ibase
I is a Cost Index at present time
Chemical Engineering, CE, Plant Cost Index
Marshall and Swift (MS) Equipment Cost Index
Nelson-Farrar (NF) Refinery Construction Cost Index
Engineering News-Record (ENR) Construction Cost Index
Cp(I) = Cp(Ibase)*(I/Ibase)
Cp(Ibase)=FT*Fm*Cbase(Ibase)

5. Cost Estimate Methods Order of Magnitude Estimate
Method of Hill
Marshall Swift for I/Ibase
Six Tenths Rule for Production Capacity
CTCI-2 (I)=CTCI-1 (Ibase)*(I/Ibase)* (Capacity2/Capacity1)0.6
Study Estimate (±35%)
Method of Lang
CTCI=1.05*fL-TCI ∑ (Ii/Ibase-i) Cp-i
Lang factors for different types of Plants
Solids -3.10, Solids&Fluids 3.62, Fluids 4.73
Sum over all major equipment
Preliminary Estimate (±20%)
Method of Guthrie
Bare module cost, CBM= Cp-base(I/Ibase)[FBM+(FdFpFm-1)]
d= design factor, p = pressure factor, m =materials factor
CTCI= ∑ CBM_i
Quote Estimate

6. Purchase Costs for Equipment
Size Factor, S, depends on type of equipment
Cp(Ibase)=A*(S)b
Cp(Ibase)=exp(Ao+A1[lnS]+A2[lnS]2+…)
Your book gives 2006 base costs
Ibase = 500 (2006) average

7. Pumps & Electric Motors
Pump Types (Centrifugal, Gear, Plunger)
Centrifugal Pump
Size factor, S=Q(Head)0.5
Base Cost, CB=exp( [ln(S)] [ln(S)]2)
Cp=FTFMatCB
Fm materials factor see Table 22.21
FT pump type factor see Table 22.20
Other types of pumps have different CB formulas
Electric Motor to drive pump
Size Factor=Power consumption, PC=PT/ηp/ηM=PB/ηM=QHρ/(33,000ηpηM)
Q= flow rate, H = head, ρ = density
Efficiencies (pump and motor) are a function of flow rate and break horsepower (power without any losses), respectively
CB=exp{ [ln(PC)] [ln(PC)] [ln(PC)] [ln(PC)]4}
Cp=FTCB
FT= motor types factor see Table 22.22
ηM=~90%
Installation, etc, FBM=3.3
CBM=FBM*∑CP

8. Fans Fan Motor size by PC=QHt(in. water)/(6,350 ηFηM)
Sizing factor is the volumetric flow rate, Q
Different CB formula for different types of fans
CP=FHFM CB
FH Head factor see Table 22.24
FM material of construction factor
Fiberglass 1.8
Stainless steel 2.5
Nickel Alloy 5.0
Motor size by PC=QHt(in. water)/(6,350 ηFηM)
ηM =~90%, FBM = 2.15
CBM=FBM*∑CP

9. Blowers Sizing factor is the power consumption, PC
Centrifugal (turbo) Blower
CB=exp{ [ln(Pc)]}
CP=Fm-fansCB
Motor
Motor size by PC=QHt(in. water)/(6,350 ηFηM)
ηM =90% , FBM = 2.15
CBM=FBM*∑CP

10. Compressors Compressor types
Centrifugal, CB=exp{ [ln(PC)]}
Reciprocating, CB=exp{ [ln(PC)]}
Screw, CB=exp{ [ln(PC)]}
Size factor is the power consumed, PC=PB/ηC
CP=FDriveFMatCB
FDrive =1 (electric motor), 1.15 (steam), 1.25 (gas turbine)
FMat = 1.0 Carbon steel, 2.5 SS, 5.0 Nickel Alloy
CBM=FBM*∑CP
FBM = 2.15

11. Heat Exchangers Types of Heat exchangers Size Factor is HX area, A
Floating, CB=exp{ [ln(A)] [ln(A)]2}
Fixed Head, CB=exp{ [ln(A)] [ln(A)]2}
U-tube, CB=exp{ [ln(A)] [ln(A)]2}
Kettle, CB=exp{ [ln(A)] [ln(A)]2}
Thermosiphon, CB=
Double pipe, CB=exp{ [ln(A)]}
Size Factor is HX area, A
CP=FpFMatFLCB
Pressure Factor, Fp= (P(psig)/100) (P(psig)/100)2
Not for double pipe
Materials Factor, Fmat=a+(A/100)b, a & b from Table 22.25
a≥1.0 note error in first row of Table 22.5
Tube Length Factor FL= 1.25 for 8 ft, 1.0 for 20 ft. on a sliding scale
CBM = FBM*CP, FBM=3.17 (S&T), 1.80 (DP), 2.17 (Fin/Fan)

12. Fired Heaters Size Factor is the heat duty, Q
CB=exp{ [ln(Q)]}
CP=FPFMatCB
FP= (P(psig)\500) (P/500)2
Fmat=1.4 Cr-Mo alloy steel, 1.7 for stainless steel
CBM = FBM*CP, FBM=2.19

13. Pressure Vessels Storage Tanks Distillation Towers Absorber Towers
Tray
Packed
Absorber Towers
Stripping Towers

14. Pressure Vessels Sizing Factor is the weight of steel, W
Horizontal Vessels, 1,000<W<920,00 lb
CB=exp{ [ln(W)] [ln(W)]2}
Vertical Vessels, 4,200<W<1,000,00 lb
CB=exp{ [ln(W)] [ln(W)]2}
Add Platform Costs,
Horizontal, 3<Di<12 ft
CPL=1580(Di)
Vertical, 3<Di<21 ft
CPL=258.1(Di)0.7396(L)
Weight, W=π(Di+ts)(L+0.8Di)tsρs
C=FMCB+CPL
FM= materials factor see Table 22.26
Installation, etc, FBM=4.16 (V), 3.05 (H)
CBM=FBM*∑CP

15. Hoop Stress Calc for thickness, ts
Design Pressure is function of operating pressure, Po
For Po> 1,000psig use Pd=1.1Po
For Po< 1,000psig but not for vacuum
Pd=exp{ [ln(Po)] [ln(Po)]2}
Thickness (Hoop Stress Calculation)
ts= PdDi/(2SE-1.2 Pd)
S = max allowable stress for steel is f(T)
E = weld efficiency (fraction)
Minimum wall thickness for given diameters
May add extra thickness for wind stresses, corrosion
Different calculation for vacuum vessels
Also account for leakage when vacuum vessel is used

16. Distillation Towers
Pressure vessel with plates or packing and additional nozzles and manholes
Tray Cost
CT=NTFNTFTTFTMCBT
NT= no. trays
FNT= 1 for NT>20 otherwise FNT=2.25/(1.0414NT)
FTT = tray type, 1.0 sieve, 1.87 bubble cap
FTM= Materials, f(D)
Carbon Steel FTM=1.0
316 SS FTM= Di
Installation, etc, FBM=4.16
CBM=FBM*∑CP

17. Packed Distillation Column
Pressure vessel with platforms plus packing
Packing Cost basis is volume of packing, VP
C=VpCPK+CDR
CPK= is installed cost per unit volume
Distributors cost, CDR

18. Absorbers/Strippers Pressure Vessel plus platforms and packing
Separate costs for blowers
Separate costs for motors

19. Other process equipment
Different sizing factors
Different basis cost equations
Same methods used for cost calculation

20. Other Process Equipment
Various Size Factors
Table 22.32